Download 888-2247-006 - Gates Harris History

TECHNICAL MANUAL
DX-10
AM BROADCAST TRANSMITTER
994 9085 002
888-2247-006
I
Introduction
II
Installation
III
Operation
IV
Theory of Operation
V
Maintenance
VI
Troubleshooting/Emergency Procedures
VII Parts List
Subsections
VIII RF
Oscillator
Buffer Amplifier
RF Amplifier Modules
Driver Combiner/Motherboard
Driver Supply Regulator
RF Multimeter
RF Combiners
Output Sample &
Output Monitor
IX
Audio
Analog Input
Analog to Digital Converter
Modulation Encoder
DC Regulator
External Interface
X
Control
Controller
LED Board
Switch Board/Meter Panel
Test Equipment
T.M. No. 888-2247-006
Printed: April 2001
Rev. L: 03/16/2009
Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2009
Harris Corporation
All rights reserved
MANUAL REVISION HISTORY
DX-10 AM TRANSMITTER
888-2247-xxx
REV. # DATE
ECN
002
05-25-88
34979
003
11-3-89
35509
004
04-19-90
35828
Rev. A 08-13-90
Rev. B 08-20-90
35988
& 36157
36059
005
005-A
005-B
005-C
005-D
005-E
005-F
005-G
005-H
005-J
005-K
005-L
005-M
005-M1
005-N
005-P
005-R
005-S
005-T
11-27-90
08-20-91
12-03-93
03-22-94
06-29-94
08-02-94
08-29-94
09-22-94
11-21-94
01-09-95
04-20-95
08-10-95
10-26-95
10-31-95
02-01-96
04-04-96
05-02-96
07-01-96
11-06-96
35532
37269
38869
38887
39025
TBD
39452
39409
TBD
39470
39813
39968
39917
Errata
41080
41151
41154
41324
41561A
005-U
005-U1
005-V
005-W
006
006-B
006-B1
006-B2
006-C
006-D
006-D1
006-E
006-E1
006-F
11-21-96
06-27-97
05-13-98
01-19-99
03-11-99
06-16-99
11-02-99
03-30-00
04-05-01
07-10-01
04-17-02
08-06-02
01-28-03
03-06-03
41576
41809
42020
42564
TBD
42963
43013
UPDATE
47169
47509
48124
48511
FSR
TBD
PAGES AFFECTED
Replace and/or add the following pages:
Title Page, Manual Revision History Page, D-10, H-15 thru H-19, H-29/H-30, K-25,
& K-26. Added page MRH-1/MRH-2
Manual converted into Ventura with multiple changes to correct errata and update
parts list and drawings.
Replaced the following pages: Title Page, MRH-1/MRH-2, iv thru x, 5-1 thru 5-31,
7-15 thru 7-20, all of Section 8, Figure 9-4, D-5 & D-6, G-3 & G-4, H-7 thru H-10,
Figure H-4, J-7 thru J-12, Figure J-3, K-13 thru K-16, Figure K-5, P-31 thru P-36,
Figure P-13, Q-30 thru Q-39, & Figure Q-12.
Replaced the following pages: Title Page, MRH-1/MRH-2, A-5, A-6, J-9, J-10, Q-30,
Q-31, Q-32, drawing 839 6208 097, 839 6208 091, & 839 6802 111
Replaced the following pages: Title Page, MRH-1/MRH-2, K-13, K-14, K-15, &
drawing 839 6208 080
Revised manual to put drawings in separate drawing package
Replaced Title Page, MRH-1/MRH-2, and page 8-2
Replaced Title Page, MRH-1/MRH-2, and page 9-1/9-2
Replaced Title Page, MRH-1/MRH-2, and pages 8-1 to 8-7
Replaced Title Page, MRH-1/MRH-2, and pages H-8 and H-9
Replaced Title Page, MRH-1/MRH-2, and page 6-20
Replaced Title Page, MRH-1/MRH-2, TOC, and all of Section K
Replaced Title Page, MRH-1/MRH-2, and pages H-8 and H-9
Replaced Title Page, MRH-1/MRH-2, and all of Section VI
Replaced Title Page, MRH-1/MRH-2, and all of Section K
Replaced Title Page, MRH-1/MRH-2, and pages Q-30 to Q-32
Replaced Title Page, MRH-1/MRH-2, all of Section VIII, and pages P-32 to P-34
Replaced Title Page, MRH-1/MRH-2, all of Section VIII
Replaced Title Page, MRH-1/MRH-2, page C-8
Replaced Title Page, MRH-1/MRH-2, and pages 2-17 to 2-22
Replaced Title Page, MRH-1/MRH-2, and page 2-7
Replaced Title Page, MRH-1/MRH-2, and pages K-7 to K-9 & Q-30 to Q-32
Replaced Title Page, MRH-1/MRH-2, and pages Q-30 to Q-32
Replaced Title Page, MRH-1/MRH-2, and pages x, 1-1, 1-8, 1-11, 1-12, 2-1 thru
2-8, Figure 3-2, 5-10, 5-19, 5-28, 6-19 thru 6-25, 7-1, 7-2, 7-14, 7-15, K-6, L-1 &
L-2, replaced Section R
Replaced Title Page, MRH-1/MRH-2, and page 1-1. Remove pages 1-16 & 1-17.
Replaced Title Page, MRH-1/MRH-2, and pages M-8 & M-9.
Replaced Title Page, MRH-1/MRH-2 and pages 5-5 and K-5
Replaced Title Page, MRH-1/MRH-2 and pages 6-20 and 6-22
Replaced Entire Manual
Replaced Title Page, MRH-1/MRH-2 and pages 2-2 and 3-8
Replaced Title Page, MRH-1/MRH-2, and all of Section VIi
Replaced Title Page, MRH-1/MRH-2, and all of Section VIi
Replaced Title page, MRH-1/MRH-2, and all of Sections V and VII
Replaced Title page, MRH-1/MRH-2, all of sections 2, 5 and H
Replaced Title Page, MRH-1/MRH-2, and all of Section VII
Replaced Title Page, MRH-1/MRH-2 and added CE documentation
Replaced Title Page, MRH-1/MRH-2 and pages 3-14, 3-15, 6-7 & 6-8
Replaced Title Page, MRH-1/MRH-2 and Section E.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
MRH-1/MRH-2
006-G
006-H
006-J
006-K
006-L
11-17-03 49774
04-21-04 50178
12-10-04 50683
04/13/05 51250
03/16/09 53733
Replaced
Replaced
Replaced
Replaced
Replaced
Title
Title
Title
Title
Title
Page, MRH-1/MRH-2 and Sections 2, 4 and 5.
Page, MRH-1/MRH-2 and Section H.
page, MRH-1/MRH-2, section 5 and A.
Page, MRH-1/MRH-2, and section J.
Page, MRH-1/MRH-2 and section 2, 4, 5, 6A.
Returns And Exchanges
Damaged or undamaged equipment should not be returned unless written approval and a
Return Authorization is received from HARRIS CORPORATION, Broadcast Systems Division. Special shipping instructions and coding will be provided to assure proper handling.
Complete details regarding circumstances and reasons for return are to be included in the
request for return. Custom equipment or special order equipment is not returnable. In those
instances where return or exchange of equipment is at the request of the customer, or
convenience of the customer, a restocking fee will be charged. All returns will be sent
freight prepaid and properly insured by the customer. When communicating with HARRIS
CORPORATION, Broadcast Systems Division, specify the HARRIS Order Number or Invoice Number.
Unpacking
Carefully unpack the equipment and preform a visual inspection to determine that no apparent damage was incurred during shipment. Retain the shipping materials until it has been
determined that all received equipment is not damaged. Locate and retain all PACKING
CHECK LISTs. Use the PACKING CHECK LIST to help locate and identify any components
or assemblies which are removed for shipping and must be reinstalled. Also remove any
shipping supports, straps, and packing materials prior to initial turn on.
Technical Assistance
HARRIS Technical and Troubleshooting assistance is available from HARRIS Field Service
during normal business hours (8:00 AM - 5:00 PM Central Time). Emergency service is
available 24 hours a day. Telephone 217/222-8200 to contact the Field Service Department
or address correspondence to Field Service Department, HARRIS CORPORATION, Broadcast Systems Division, P.O. Box 4290, Quincy, Illinois 62305-4290, USA. Technical Support
by e-mail: [email protected]. The HARRIS factory may also be contacted through a FAX
facility (217/221-7096).
Replaceable Parts Service
Replacement parts are available 24 hours a day, seven days a week from the HARRIS
Service Parts Department. Telephone 217/222-8200 to contact the service parts department
or address correspondence to Service Parts Department, HARRIS CORPORATION, Broadcast Systems Division, P.O. Box 4290, Quincy, Illinois 62305-4290, USA. The HARRIS factory may also be contacted through a FAX facility (217/221-7096).
NOTE
The # symbol used in the parts list means used with (e.g. #C001 = used with C001).
Guide to Using Harris Parts List Information
The Harris Replaceable Parts List Index portrays a tree structure with the major items being leftmost in the index.
The example below shows the Transmitter as the highest item in the tree structure. If you were to look at the bill of
materials table for the Transmitter you would find the Control Cabinet, the PA Cabinet, and the Output Cabinet. In
the Replaceable Parts List Index the Control Cabinet, PA Cabinet, and Output Cabinet show up one indentation level
below the Transmitter and implies that they are used in the Transmitter. The Controller Board is indented one level
below the Control Cabinet so it will show up in the bill of material for the Control Cabinet. The tree structure of this
same index is shown to the right of the table and shows indentation level versus tree structure level.
Example of Replaceable Parts List Index and equivalent tree structure:
The part number of the item is shown to the right of the description as is the page in the manual where the bill for
that part number starts.
Inside the actual tables, four main headings are used:
Table #-#. ITEM NAME - HARRIS PART NUMBER - this line gives the information that corresponds to the
Replaceable Parts List Index entry;
HARRIS P/N column gives the ten digit Harris part number (usually in ascending order);
DESCRIPTION column gives a 25 character or less description of the part number;
REF. SYMBOLS/EXPLANATIONS column 1) gives the reference designators for the item (i.e., C001, R102,
etc.) that corresponds to the number found in the schematics (C001 in a bill of material is equivalent to C1 on the
schematic) or 2) gives added information or further explanation (i.e., “Used for 208V operation only,” or “Used
for HT 10LS only,” etc.).
Inside the individual tables some standard conventions are used:
A # symbol in front of a component such as #C001 under the REF. SYMBOLS/EXPLANATIONS column means
that this item is used on or with C001 and is not the actual part number for C001.
In the ten digit part numbers, if the last three numbers are 000, the item is a part that Harris has purchased and
has not manufactured or modified. If the last three numbers are other than 000, the item is either manufactured by
Harris or is purchased from a vendor and modified for use in the Harris product.
The first three digits of the ten digit part number tell which family the part number belongs to - for example, all
electrolytic (can) capacitors will be in the same family (524 xxxx 000). If an electrolytic (can) capacitor is found
to have a 9xx xxxx xxx part number (a number outside of the normal family of numbers), it has probably been
modified in some manner at the Harris factory and will therefore show up farther down into the individual parts
list (because each table is normally sorted in ascending order). Most Harris made or modified assemblies will
have 9xx xxxx xxx numbers associated with them.
The term “SEE HIGHER LEVEL BILL” in the description column implies that the reference designated part
number will show up in a bill that is higher in the tree structure. This is often the case for components that may
be frequency determinant or voltage determinant and are called out in a higher level bill structure that is more
customer dependent than the bill at a lower level.
2-02-93
WARNING
THE CURRENTS AND VOLTAGES IN THIS EQUIPMENT ARE DANGEROUS. PERSONNEL MUST AT ALL TIMES OBSERVE SAFETY WARNINGS, INSTRUCTIONS
AND REGULATIONS.
This manual is intended as a general guide for trained and qualified personnel who are aware of the dangers inherent in
handling potentially hazardous electrical/electronic circuits. It is not intended to contain a complete statement of all safety
precautions which should be observed by personnel in using this or other electronic equipment.
The installation, operation, maintenance and service of this equipment involves risks both to personnel and equipment, and
must be performed only by qualified personnel exercising due care. HARRIS CORPORATION shall not be responsible for
injury or damage resulting from improper procedures or from the use of improperly trained or inexperienced personnel
performing such tasks.
During installation and operation of this equipment, local building codes and fire protection standards must be observed.
The following National Fire Protection Association (NFPA) standards are recommended as reference:
- Automatic Fire Detectors, No. 72E
- Installation, Maintenance, and Use of Portable Fire Extinguishers, No. 10
- Halogenated Fire Extinguishing Agent Systems, No. 12A
WARNING
ALWAYS DISCONNECT POWER BEFORE OPENING COVERS, DOORS, ENCLOSURES, GATES, PANELS OR SHIELDS. ALWAYS USE GROUNDING STICKS AND
SHORT OUT HIGH VOLTAGE POINTS BEFORE SERVICING. NEVER MAKE INTERNAL ADJUSTMENTS, PERFORM MAINTENANCE OR SERVICE WHEN ALONE
OR WHEN FATIGUED.
Do not remove, short-circuit or tamper with interlock switches on access covers, doors, enclosures, gates, panels or shields.
Keep away from live circuits, know your equipment and don’t take chances.
WARNING
IN CASE OF EMERGENCY ENSURE THAT POWER HAS BEEN DISCONNECTED.
WARNING
IF OIL FILLED OR ELECTROLYTIC CAPACITORS ARE UTILIZED IN YOUR
EQUIPMENT, AND IF A LEAK OR BULGE IS APPARENT ON THE CAPACITOR
CASE WHEN THE UNIT IS OPENED FOR SERVICE OR MAINTENANCE, ALLOW
THE UNIT TO COOL DOWN BEFORE ATTEMPTING TO REMOVE THE DEFECTIVE CAPACITOR. DO NOT ATTEMPT TO SERVICE A DEFECTIVE CAPACITOR
WHILE IT IS HOT DUE TO THE POSSIBILITY OF A CASE RUPTURE AND SUBSEQUENT INJURY.
i
ii
FIRST-AID
Personnel engaged in the installation, operation, maintenance or servicing of this equipment are urged to become familiar
with first-aid theory and practices. The following information is not intended to be complete first-aid procedures, it is a
brief and is only to be used as a reference. It is the duty of all personnel using the equipment to be prepared to give
adequate Emergency First Aid and thereby prevent avoidable loss of life.
Treatment of Electrical Burns
1.
Extensive burned and broken skin
a.
Cover area with clean sheet or cloth. (Cleanest available cloth article.)
b.
Do not break blisters, remove tissue, remove adhered particles of clothing, or apply any salve or ointment.
c.
Treat victim for shock as required.
d.
Arrange transportation to a hospital as quickly as possible.
e.
If arms or legs are affected keep them elevated.
NOTE
If medical help will not be available within an hour and the victim is
conscious and not vomiting, give him a weak solution of salt and soda:
1 level teaspoonful of salt and 1/2 level teaspoonful of baking soda to
each quart of water (neither hot or cold). Allow victim to sip slowly
about 4 ounces (a half of glass) over a period of 15 minutes. Discontinue fluid if vomiting occurs. (Do not give alcohol.)
2.
Less severe burns - (1st & 2nd degree)
a.
Apply cool (not ice cold) compresses using the cleanest available cloth article.
b.
Do not break blisters, remove tissue, remove adhered particles of clothing, or apply salve or ointment.
c.
Apply clean dry dressing if necessary.
d.
Treat victim for shock as required.
e.
Arrange transportation to a hospital as quickly as possible.
f.
If arms or legs are affected keep them elevated.
REFERENCE:
ILLINOIS HEART ASSOCIATION
AMERICAN RED CROSS STANDARD FIRST AID AND PERSONAL SAFETY MANUAL (SECOND EDITION)
iii
Table of Contents
Section I
Introduction/Specifications
Scope and Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Section II
Installation
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Returns and Exchanges . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Factory Test Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
General Installation Information. . . . . . . . . . . . . . . . . . . . . . 2-1
Transmitter Space Requirements . . . . . . . . . . . . . . . . . . . 2-1
Access for External Connections . . . . . . . . . . . . . . . . . . . 2-1
AC Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Transmitter Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Transmitter Grounding & RF Output Connections . . . . . 2-3
Setup Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
General Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Equipment Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Pre-Installation Inspection . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Mechanical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Equipment Positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Transmitter Leveling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Ground Strap Installation . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Delta and Wye Connections . . . . . . . . . . . . . . . . . . . . . . . 2-5
High Voltage Transformer, Primary winding Terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
3 Wire Delta AC Power Wiring . . . . . . . . . . . . . . . . . . . . 2-5
AC Power Wiring, three wire Delta Configuration . . . . . 2-5
Transformer connections, 3-WIRE DELTA
CONNECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Blower Motor Junction Box Strapping . . . . . . . . . . . . . . 2-5
AC Input Power Connection . . . . . . . . . . . . . . . . . . . . . . 2-5
4 Wire WYE AC Power Wiring. . . . . . . . . . . . . . . . . . . . 2-7
AC Power Wiring, Four Wire WYE Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Transformer Connections, 3-WIRE WYE
Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Blower Motor Junction Box Strapping . . . . . . . . . . . . . . 2-7
Other “FOUR WIRE WYE” Connections . . . . . . . . . . . . 2-7
AC Input Power Connection . . . . . . . . . . . . . . . . . . . . . . 2-7
Power Wiring Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Meter Shunt Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Controller Battery Backup . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Customer Interface Connections. . . . . . . . . . . . . . . . . . . . . . 2-9
Audio Input Connections . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Audio Phasing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Audio Source Impedance . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Selecting Source Impedance . . . . . . . . . . . . . . . . . . . 2-9
RF Output Terminal Installation. . . . . . . . . . . . . . . . . . . . 2-9
Dummy Antenna Information. . . . . . . . . . . . . . . . . . . . . 2-10
External Interlock (Fail-safe) . . . . . . . . . . . . . . . . . . . . . 2-10
Using The External Interlock . . . . . . . . . . . . . . . . . 2-10
PA Turn Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Modulation Monitor Connection . . . . . . . . . . . . . . . . . . 2-10
iv
Frequency Monitor Connection . . . . . . . . . . . . . . . . . .
Remote Control Connections . . . . . . . . . . . . . . . . . . . . . .
Functions Which Can Be Controlled Or Monitored . .
Interface Information . . . . . . . . . . . . . . . . . . . . . . .
Remote “CONTROL” . . . . . . . . . . . . . . . . . . . . . .
Remote “STATUS” Indications . . . . . . . . . . . . . .
Remote Meter Readings (“MONITOR” Outputs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Explanation of Selected Functions . . . . . . . . . . . . . . . . . .
External Interlock (FAIL-SAFE) . . . . . . . . . . . . . . . . .
“OFF” Function (Remote “OFF” Control) . . . . . . . . . .
PA Turn OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“OFF” Function, “PA Turn OFF,” and External Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of OFF, PA Turn OFF, and External Interlock
Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmitter Turn ON . . . . . . . . . . . . . . . . . . . . . . . . . . .
Raise/Lower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Forward” and “Reflected” Power, Remote Meter
Readings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bandpass Filter VSWR and Antenna VSWR, Remote Meter Readings . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Drive estimate, Remote Meter Reading (at TB19) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Monitor Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Status Indications . . . . . . . . . . . . . . . . . . . . . . .
RF Combiner Crowbar not Operational . . . . . . . . . . . .
Pre-Turn ON Checks; Mechanical . . . . . . . . . . . . . . . . . .
Pre-Turn ON Checks; Electrical . . . . . . . . . . . . . . . . . . . .
Initial Turn On Procedures . . . . . . . . . . . . . . . . . . . . . . . .
Low Voltage Power Supplies Check . . . . . . . . . . . . . .
Fan Rotation Check . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Driver Operation Check . . . . . . . . . . . . . . . . . . . . .
PA Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tuning, at about 1 Kilowatt Output . . . . . . . . . . .
Tuning and Verifying Correct Operation at
High Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulation Monitor;Setting Sample Levels. . . . . . . . .
Setting Modulation Monitor Sample Level. . . . . .
Controller;Battery Backup. . . . . . . . . . . . . . . . . . . . . . .
Installing Batteries . . . . . . . . . . . . . . . . . . . . . . . . .
Modulation Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Gain Adjustment. . . . . . . . . . . . . . . . . . . . . . . . .
Recording Normal Meter Readings . . . . . . . . . . . . . . .
Final Matching Into Antenna . . . . . . . . . . . . . . . . . . . .
Removing The Shorting Straps On L103 and
L104 if required. . . . . . . . . . . . . . . . . . . . . . . . . . .
Finishing Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional Audio Phasing . . . . . . . . . . . . . . . . . . . . . . . .
Section III
Operation
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Daily Preoperational Checkout (Local Control). . . . . . . . .
Daily Preoperational Checkout (Remote Control) . . . . . . .
Transmitter Turn-On Procedure . . . . . . . . . . . . . . . . . . . . .
Transmitter Turn-OFF Procedure . . . . . . . . . . . . . . . . . . . .
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-11
2-11
2-11
2-11
2-11
2-12
2-12
2-12
2-12
2-12
2-12
2-12
2-13
2-13
2-13
2-13
2-13
2-13
2-13
2-13
2-13
2-13
2-14
2-14
2-15
2-15
2-16
2-16
2-16
2-17
2-17
2-17
2-18
2-18
2-18
2-18
2-18
2-19
2-19
2-19
2-19
3-1
3-1
3-1
3-1
3-1
3-2
03/16/2009
Emergency Operating Procedures. . . . . . . . . . . . . . . . . . . .
AC Power Failure (When not using Controller
Backup Battery) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AC Power Failure (When Controller Backup Battery
is used) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmitter Will Not Come ON . . . . . . . . . . . . . . . . . . .
Transmitter Shuts OFF . . . . . . . . . . . . . . . . . . . . . . . . . .
Fault status indications will not clear when reset, or
Fault Indications Continue to Occur . . . . . . . . . . . . . .
Remote Status LED is Red . . . . . . . . . . . . . . . . . . . . . . .
Oscillator, Buffer Amp or Driver Fault . . . . . . . . . . . . .
RF Amp “Envelope OK” Fault (Remote “Envelope
Error” Fault) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Input +15V or -15V Fault. A/D Converter
+15V, -15V, +5V Fault . . . . . . . . . . . . . . . . . . . . . . . . .
A/D Converter Conversion Error Fault. . . . . . . . . . . . . .
Modulation Encoder Cable Interlock Fault . . . . . . . . . .
DC Regulator +5V or B- Fault . . . . . . . . . . . . . . . . . . . .
Output Monitor +5V or -5V Fault . . . . . . . . . . . . . . . . .
Output Monitor VSWR Fault . . . . . . . . . . . . . . . . . . . . .
Interlocks: External, Air or Door Interlock Fault. . . . . .
Overloads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Over Current . . . . . . . . . . . . . . . . . . . . . . . .
VSWR Sensor “Status” Indicator is Red (Remote
VSWR Self Test Pass/Fail Fault) . . . . . . . . . . . . . . . . .
Type 3 Fault Indication (Remote Indication Only) . . . .
Bandpass Filter VSWR Fault (Remote: “Internal
VSWR Fault”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Antenna VSWR Fault (Remote: “External VSWR
Fault”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VSWR Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VSWR Fault Indication stays ON . . . . . . . . . . . . . .
Tuning and Loading Control Adjustment. . . . . . . . . . . . . .
Section IV
System Operation
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Protection of Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discharging the High Voltage Supply . . . . . . . . . . . . . .
Location of Door Interlocks and Grounding Switches. .
Door Interlock Switches . . . . . . . . . . . . . . . . . . . . .
Grounding Switches . . . . . . . . . . . . . . . . . . . . . . . . .
Non-interlocked compartment . . . . . . . . . . . . . . . . .
Block Diagram Description. . . . . . . . . . . . . . . . . . . . . . . . .
RF Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Amplifier Stages . . . . . . . . . . . . . . . . . . . . . . . .
Driver Supply Regulator . . . . . . . . . . . . . . . . . . . . .
RF Status Indications: RF Sense Data Lines . . . . .
Status Indications as Troubleshooting Aids . . . . . .
Combiner and Splitter . . . . . . . . . . . . . . . . . . . . . . .
Power Amplifier. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Combiners, Output Network and Output Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Input and Modulation Section . . . . . . . . . . . . . . .
Controller Section (“Controller” and “LED” Boards) . .
Transmitter Power Supplies . . . . . . . . . . . . . . . . . . . . . .
High Voltage Supply . . . . . . . . . . . . . . . . . . . . . . . .
Low Voltage Supply . . . . . . . . . . . . . . . . . . . . . . . .
Driver Supply Regulator, A22. . . . . . . . . . . . . . . . .
03/16/2009
3-2
3-2
3-2
3-2
3-3
3-3
3-3
3-3
3-3
3-3
3-3
3-3
3-3
3-3
3-3
3-3
3-4
3-4
3-4
3-4
3-4
3-4
3-4
3-4
3-5
4-1
4-1
4-1
4-1
4-2
4-2
4-2
4-2
4-2
4-8
4-8
4-8
4-8
4-8
4-8
4-8
4-8
4-8
4-9
4-9
4-9
4-9
4-9
DC Regulator Board, A30 . . . . . . . . . . . . . . . . . . . . 4-9
External Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Digital Terms and Concepts. . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Quantized Amplitude Modulation . . . . . . . . . . . . . . . . . . . 4-10
Amplitude Modulation - A Review . . . . . . . . . . . . . . . . 4-11
Amplitude Modulation in the DX-10 Transmitter . . . . 4-11
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Analog to Digital Conversion . . . . . . . . . . . . . . . . . . . . . . 4-12
SAMPLE TIME INTERVAL . . . . . . . . . . . . . . . . . . . . 4-12
Digital to Analog Conversion . . . . . . . . . . . . . . . . . . . . . . 4-13
DX-10 Power Amplifier Section Principles . . . . . . . . . . . 4-13
“BIG STEPS” and BINARY STEPS . . . . . . . . . . . . . . 4-14
Modulation Encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
RF Output Bandpass Filter. . . . . . . . . . . . . . . . . . . . . . . 4-14
Switching RF Amplifiers ON or OFF . . . . . . . . . . . . . . 4-14
RF Combiner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15
Summary: DX-10 Digital Modulation. . . . . . . . . . . . . . . . 4-15
Engineering Description. . . . . . . . . . . . . . . . . . . . . . . . . 4-15
Digital Modulation Characteristics . . . . . . . . . . . . . . . . 4-15
AC Power Circuits in the DX-10. . . . . . . . . . . . . . . . . . . . 4-15
Transient Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15
Overvoltage and Undervoltage Protection. . . . . . . . . . . 4-16
“Brown-Out” Protection. . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Phase Loss Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Transmitter Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Turning Supplies ON and OFF . . . . . . . . . . . . . . . . . . . 4-16
Low Voltage Supply . . . . . . . . . . . . . . . . . . . . . . . . 4-16
High Voltage Supply . . . . . . . . . . . . . . . . . . . . . . . 4-16
Low Voltage Power Supply, Circuit Description . . . . . . . 4-16
Low Voltage Supply, Primary Power Circuit . . . . . . . . 4-16
Power Distribution Board, A39 . . . . . . . . . . . . . . . . . . . 4-17
High Voltage Power Supply, Circuit Description. . . . . . . 4-17
High Voltage Supply Transformer T1. . . . . . . . . . . . . . 4-17
High Voltage Supply Primary Power Contactors . . . . . 4-17
High Voltage Step-Start (K1, K2, R31-R33) . . . . . . . . 4-17
12 Phase Supply and Rectifier Assembly . . . . . . . . . . . 4-17
Supply Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
Fuses in DC Lines . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
Power Supply Discharge Circuit . . . . . . . . . . . . . . . . . . 4-18
Mechanical Shorting Switches, S9 AND S10 . . . . 4-18
+115VDC and +230VDC Supply Filter Capacitor Discharge Paths . . . . . . . . . . . . . . . . . . . . . 4-18
Supply Current Meter, M2. . . . . . . . . . . . . . . . . . . . . . . . . 4-18
Fuse Board, A24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Voltage Sample Circuits on the Fuse Board . . . . . . . . . 4-19
“Power Supply Protection” Sample . . . . . . . . . . . . 4-19
“Voltmeter” Sample . . . . . . . . . . . . . . . . . . . . . . . . 4-19
High Voltage “Overvoltage” Sample. . . . . . . . . . . 4-19
“Analog Input” Sample . . . . . . . . . . . . . . . . . . . . . 4-19
Power Supply Sample. . . . . . . . . . . . . . . . . . . . . . . 4-19
Blower B1, Air Flow Sensing Unit S7 and Temperature Actuated Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Blower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Air Flow Sensing Unit S7 and Temperature
Actuated Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Interlocks and Interlock Relays . . . . . . . . . . . . . . . . . . . . . 4-20
Voltage Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20
Voltage Regulator Assemblies. . . . . . . . . . . . . . . . . . . . 4-20
Other Voltage Regulators. . . . . . . . . . . . . . . . . . . . . . . . 4-20
888-2247-006
WARNING: Disconnect primary power prior to servicing.
v
RF Circuit Descriptions, For RF Circuits Not on
Printed Circuit Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Driver Combiner Description . . . . . . . . . . . . . . . . . .
Grounding Block for the Driver and output Combiner Secondary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Drive Splitter, A15 . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Drive Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Power Amplifier Description . . . . . . . . . . . . . . . . . .
RF Output Combiner Description . . . . . . . . . . . . . . . . .
RF Samples for the Output Combiner . . . . . . . . . .
Bandpass Filter (Output Network) Description . . . . . . .
There are no Operator Tuning Adjustments
for the Bandpass Filter/Output Network . . . . . . . .
Bandpass Filter/Output Network Circuit Description . .
Output Sample/Output Monitor . . . . . . . . . . . . . . . . . . .
TEE Matcher: “Tune” and “Load” Controls. . . . . . . . .
Adjusting “Tuning” and “Loading” Controls. . . . .
To adjust Tuning and Loading:. . . . . . . . . . . . . . . .
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulation Monitor Sample Coil (L107) . . . . . . . . . . .
Spark Gap, E101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-20
4-20
4-20
4-21
4-21
4-21
4-22
4-22
4-22
4-22
4-22
4-23
4-23
4-23
4-23
4-23
4-23
4-23
Section V
Maintenance/Alignments
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance Logbook. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discrepancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Time/Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corrective Action . . . . . . . . . . . . . . . . . . . . . . . . . . .
Defective Parts(s) . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Elapse Time . . . . . . . . . . . . . . . . . . . . . . . . .
Name of Repairman . . . . . . . . . . . . . . . . . . . . . . . . .
Station Engineer . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance Of Components . . . . . . . . . . . . . . . . . . . . . .
Transistors and Integrated Circuits . . . . . . . . . . . . . .
Capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fixed Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Variable Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Indicators and Front Panel Switches. . . . . . . . . . . . .
Printed Circuit Boards . . . . . . . . . . . . . . . . . . . . . . . .
Air System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corrective Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Boards and Components on Boards . . . . . . . .
Boards which can be Replaced with No Adjustments . . . .
Boards which Require Preset Switch Settings or
Jumper Plug Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulation Encoder A36 . . . . . . . . . . . . . . . . . . . . . . . . .
Controller A38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buffer Amplifier A16 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Predriver A10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver Combiner/Motherboard A14 . . . . . . . . . . . . . . . . .
Binary Combiner/Motherboard A18 . . . . . . . . . . . . . . . .
Printed Circuit Boards which Require Adjustments . . . . . .
A to D Converter A34 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Delay Adjustment R78 . . . . . . . . . . . . . . . . . . . . . . .
vi
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-1
5-2
5-2
5-2
5-2
5-2
5-2
5-2
5-2
5-2
5-2
5-3
5-3
5-3
5-3
5-3
5-3
5-4
5-4
5-4
5-4
5-4
Offset Adjustment R7 . . . . . . . . . . . . . . . . . . . . . . . 5-4
Analog Input Board A35 . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Maximum Power Adjust A35R27 . . . . . . . . . . . . . . 5-5
Modulated B- Adjustments A35R85 (Gain)
and A35R84 (Offset) . . . . . . . . . . . . . . . . . . . . . . . 5-5
Audio Gain Adjust A35R15 . . . . . . . . . . . . . . . . . . 5-5
Dither Level Adjust A35R43. . . . . . . . . . . . . . . . . . 5-5
Oscillator A17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Carrier Frequency Adjust A17C1 and A17C3 . . . . 5-6
Oscillator Sync Adjustment A17S1 and
A17L4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Driver Supply Regulator A22 . . . . . . . . . . . . . . . . . . . . . 5-6
Open Loop Adjust A22R2, Closed Loop Adjust A22R12, Loop Select A22S1 . . . . . . . . . . . . . 5-6
DC Regulator A30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Modulated B- Level A30R38, and Clip Adjust A30R39 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Output Monitor A27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
DETECTOR NULL (Antenna) Adjustment . . . . . . 5-7
DETECTOR NULL (Bandpass Filter) Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Fine Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Trip Threshold Adjustment . . . . . . . . . . . . . . . . . . . 5-8
Forward/Reflected Power Adjustments C6
and C40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Modulation Monitor Sample Adjustments . . . . . . . 5-9
LED Board Replacements A32. . . . . . . . . . . . . . . . . . . . 5-9
Overload Adjustment Procedures . . . . . . . . . . . . . . . . . . 5-9
Under drive Overload A32R92 and Overdrive Overload A32R88. . . . . . . . . . . . . . . . . . . . . 5-9
Average PA Current Overload Set A32R102 . . . . 5-10
Peak PA Current Overload Set A32R98 . . . . . . . . 5-10
Power Supply Protection Overload A32R23 . . . . 5-10
Envelope Error Fault Indicator A32R65
(Level) and A32R68 (Offset) . . . . . . . . . . . . . . . . 5-10
Board Replacement Instructions . . . . . . . . . . . . . . . . . . . . 5-11
Main Combiner/Motherboard Replacement A19 and
A20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Replacement of the Main Combiner/Motherboards . . . 5-11
Lower Main Combiner/Motherboard Replacement . . . 5-11
Binary Combiner/Motherboard Removal and Replacement A18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Driver Combiner/Motherboard A14 Removal and Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Replacement of the Driver Combiner/Motherboard. . . 5-12
RF Driver Splitter A15, Removal and Replacement . . 5-12
Blower Motor B1 Replacement . . . . . . . . . . . . . . . . . . 5-13
Other Transmitter Circuit Checks . . . . . . . . . . . . . . . . . . . 5-13
Airflow Switch S7 Adjustment . . . . . . . . . . . . . . . . . . . 5-13
Tuning/Frequency Change Procedure. . . . . . . . . . . . . . . . 5-13
Test Equipment Required for Frequency Change . . . . 5-13
Installation of Frequency Determined Components . . . 5-14
Setting of Frequency Determined Jumpers and
Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
DX10/15 Output Network Tuning . . . . . . . . . . . . . . . . 5-14
RF Circuits Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Oscillator A17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Buffer A16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Predriver Adjustment A10 . . . . . . . . . . . . . . . . . . . 5-16
RF Driver Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Initial Tuning at Low Power (1 kW) . . . . . . . . . . . . . .
Output Monitor A27 Adjustments . . . . . . . . . . . . . . . .
DETECTOR NULL (Antenna) Adjustment . . . . .
DETECTOR NULL (Bandpass Filter) Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fine Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Trip Threshold Adjustment . . . . . . . . . . . . . . . . . .
Forward/Reflected Power Adjustments C6
and C40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulation Monitor Sample Adjustments . . . . . .
Final Initial tuning at low Power . . . . . . . . . . . . . . . . .
Modulated B-Check . . . . . . . . . . . . . . . . . . . . . . . .
A to D Phasing Check . . . . . . . . . . . . . . . . . . . . . .
Initial Tuning at High Power (10 kW) . . . . . . . . . . . . .
Modulated B-Check . . . . . . . . . . . . . . . . . . . . . . . .
A to D Phasing Check . . . . . . . . . . . . . . . . . . . . . .
Final Output Network Tap Settings . . . . . . . . . . . . . . .
Bandpass Filter Response . . . . . . . . . . . . . . . . . . .
Output Monitor A27 Final Adjustments. . . . . . . . . . . .
Antenna and Bandpass Filter Final Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forward and Reflected Power Null Adjustments A27C3 and A27C4 . . . . . . . . . . . . . . . . . .
Modulation Monitor Sample Adjustments . . . . . .
Oscillator Sync Adjustment A17S1 and
A17L4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Completion of Basic Frequency Change of DX-10 . . .
Binary Amplifier Phase Alignment . . . . . . . . . . . .
Binary Amplitude Alignment . . . . . . . . . . . . . . . . . . . .
Neutralization Adjustment. . . . . . . . . . . . . . . . . . . . . . .
Overall Modulated B- Adjustment . . . . . . . . . . . . . . . .
Gain Adjust A35R85 . . . . . . . . . . . . . . . . . . . . . . .
Offset Adjustment A35R84 . . . . . . . . . . . . . . . . . .
Modulated B- Level A30R38 DC Regulator
board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clip Adjustment A30R39 DC Regulator . . . . . . .
Other Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Gain Adjust A35R15 . . . . . . . . . . . . . . . . .
Offset Adjust A34R75 . . . . . . . . . . . . . . . . . . . . . .
Dither Adjust A35R43 . . . . . . . . . . . . . . . . . . . . . .
Envelope Error Fault Adjusts A32R65 and
A32R68 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AM Stereo Installation and Tuning Hints. . . . . . . . . . . . .
Interfacing For Stereo . . . . . . . . . . . . . . . . . . . . . . . . . .
Adjustments that affect IPM: . . . . . . . . . . . . . . . . . . . .
RF Driver Tune L2 . . . . . . . . . . . . . . . . . . . . . . . .
Bandpass Tuning C101 . . . . . . . . . . . . . . . . . . . . .
Section VI
Troubleshooting
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Troubleshooting, Critical OFF-AIR Situations . . . .
Symptom: Transmitter will Not Turn On-No Front
Panel Indicators are Illuminated . . . . . . . . . . . . . . . . . .
Loss of AC Power . . . . . . . . . . . . . . . . . . . . . . . . . .
Loss of +5V Supply on LED board . . . . . . . . . . . .
Loose Ribbon or Amp Connectors . . . . . . . . . . . . .
Symptom: Transmitter Will Not Turn ON-All Front
Panel Indicators Are Illuminated Green. . . . . . . . . . . . .
03/16/2009
5-18
5-18
5-18
5-19
5-19
5-19
5-20
5-20
5-20
5-20
5-21
5-21
5-21
5-21
5-21
5-22
5-22
5-22
5-22
5-22
5-22
5-23
5-23
5-23
5-24
5-24
5-24
5-24
5-24
5-24
5-25
5-25
5-25
5-25
5-25
5-25
5-25
5-25
5-25
5-25
6-1
6-1
6-1
6-1
6-1
6-1
6-1
+5V “B” Circuit Not Up To Operating Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contactor Turn On Logic . . . . . . . . . . . . . . . . . . . . .
Contactor Drive Circuitry . . . . . . . . . . . . . . . . . . . . .
Open Contactor Coil On K1 or K2 . . . . . . . . . . . . .
Symptom: Transmitter Will Not Turn ON-One or
More of the Front Panel Indicators is Illuminated
Red. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: Transmitter Will Turn ON but Immediately Turns OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmitter Faults . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: Transmitter Turns ON but there is NO
Power Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PA Turn-Off Command Given To Transmitter . . . .
PA Turn-Off Switch Set to the PA OFF Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External PA Turn-Off Circuit Activated . . . . . . . . .
Transmitter Type 4 and Type 5 Faults. . . . . . . . . . .
Power Output Of Transmitter Is Lowered To
Zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: Transmitter Turns ON but Transmitter
Output is Lower than Normal. . . . . . . . . . . . . . . . . . . . .
Antenna VSWR Caused By An Impedance
Change In The Transmitter Load . . . . . . . . . . . . . .
Bandpass Filter VSWR Caused By Problems
In The Output Network . . . . . . . . . . . . . . . . . . . . . .
Symptom: Transmitter Turns ON but Transmitter
will Not Modulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulation Not Reaching Transmitter . . . . . . . . . .
Analog Input Board . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Front Panel Indicator Faults. . . . . . . . . . .
Overloads- Intermittent or Continuous (indicator
RED or AMBER) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Main Power Supply Overcurrent Fault . . . . . . . . . . . . . .
Random Faults With Audio . . . . . . . . . . . . . . . . . . .
Faults With Tone Modulation . . . . . . . . . . . . . . . . .
Supply Current Overloads on Turn On . . . . . . . . . .
Main Power Supply-Overvoltage Fault . . . . . . . . . . . . . . . .
Supply Voltage Too High. . . . . . . . . . . . . . . . . . . . .
Main Power Supply-Supply Fault . . . . . . . . . . . . . . . . . .
Input AC 3 Phase Line Imbalance . . . . . . . . . . . . . .
Open High Voltage Rectifier(s) . . . . . . . . . . . . . . . .
Failed High Voltage Transformer . . . . . . . . . . . . . .
Low Frequency, High Level Modulation. . . . . . . . .
RF Driver-Underdrive Fault. . . . . . . . . . . . . . . . . . . . . . .
High Voltage Supply Short . . . . . . . . . . . . . . . . . . .
Failed Driver Supply . . . . . . . . . . . . . . . . . . . . . . . .
No Drive To The Driver Stage. . . . . . . . . . . . . . . . .
RF Driver Module Failure . . . . . . . . . . . . . . . . . . . .
Excessive RF Amplifier Failure . . . . . . . . . . . . . . . .
Driver Supply Regulator Failure . . . . . . . . . . . . . . .
Driver Supply Regulator Loop Select . . . . . . . . . . .
Severe Driver Mistuning . . . . . . . . . . . . . . . . . . . . .
Drive Sensing Circuit Failure. . . . . . . . . . . . . . . . . .
RF Driver-Overdrive Fault. . . . . . . . . . . . . . . . . . . . . . . . . .
Driver Supply Regulator Failure . . . . . . . . . . . . . . .
Driver Supply Regulator Loop Select . . . . . . . . . . .
Drive Sensing Circuit Failure. . . . . . . . . . . . . . . . . .
Interlocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Door Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-1
6-1
6-1
6-1
6-2
6-2
6-2
6-2
6-2
6-2
6-2
6-2
6-2
6-2
6-3
6-3
6-3
6-3
6-3
6-3
6-3
6-3
6-3
6-4
6-5
6-5
6-5
6-5
6-5
6-5
6-5
6-6
6-6
6-6
6-6
6-6
6-6
6-6
6-6
6-6
6-7
6-7
6-7
6-7
6-7
6-7
6-7
6-7
vii
External Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
External Interlock Terminals Open. . . . . . . . . . . . . . 6-7
External Interlock Fuse F6 . . . . . . . . . . . . . . . . . . . . 6-7
External Interlock Relay K4 . . . . . . . . . . . . . . . . . . . 6-8
Air Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Blower Not Operating Properly, Failed/Running Backward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Top Air Exhaust Restricted. . . . . . . . . . . . . . . . . . . . 6-8
Center Rear Panel Open . . . . . . . . . . . . . . . . . . . . . . 6-8
Air Interlock Sensing Circuitry. . . . . . . . . . . . . . . . . 6-8
Air Interlock Switch S7. . . . . . . . . . . . . . . . . . . . . . . 6-8
All Other Front Panel Faults . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Oscillator Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Buffer Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Predriver Fault. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
RF Amp Envelope Error Fault . . . . . . . . . . . . . . . . . . . . . 6-9
Analog Input +15V and -15V Supply Faults. . . . . . . . . . 6-9
A to D Converter +15V, -15V, and +5V Supply
Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
A to D Converter Conversion Error Fault . . . . . . . . . . . 6-10
Modulation Encoder Cable Interlock . . . . . . . . . . . . . . . 6-10
All RF Amplifier Modules Are In Place . . . . . . . . 6-10
All Modulation Encoder Ribbon cables Are
In Place . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Isolating a Cable Interlock Problem . . . . . . . . . . . . 6-10
DC Regulator +5V and B- Supply Faults . . . . . . . . . . . 6-10
Output Monitor +5V and -5V Supply Faults. . . . . . . . . 6-10
Output Monitor VSWR Faults . . . . . . . . . . . . . . . . . . . . 6-10
Two Stage VSWR Action. . . . . . . . . . . . . . . . . . . . . . . . 6-11
First Stage VSWR Protection: . . . . . . . . . . . . . . . . . . . . 6-11
Symptom: VSWR LED Flashes Red.. . . . . . . . . . . 6-11
Second Stage VSWR Protection: . . . . . . . . . . . . . . . . . . 6-11
Symptom: The VSWR goes to Red and Remains on. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Combination of both Stages of the VSWR Circuit
Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Symptom: The VSWR LED flashes then remains lit RED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Antenna VSWR Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Antenna VSWR Caused By An Impedance
Change In The Transmitter Load . . . . . . . . . . . . . 6-11
Bandpass Filter VSWR Fault . . . . . . . . . . . . . . . . . . . . . 6-12
Bandpass Filter VSWR Caused By Problems . . . . 6-12
Initial Troubleshooting-less Serious, Not OFF AIR
Situations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Symptom: RF Output and PA Current Lower than
Normal-THD may be Higher and RF Amp Envelope Error LED is Red or Flashing Red. . . . . . . . . . . . 6-12
Failed RF Amplifier Module. . . . . . . . . . . . . . . . . . 6-12
Symptom: RF Output and PA Current Lower than
Normal-Antenna and/or Bandpass Filter VSWR Indicators are RED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Intermittent VSWR Condition Causing
Power Foldback . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Symptom: Loss of Positive Peak Capability . . . . . . . . . 6-12
Power Supply Voltage Low . . . . . . . . . . . . . . . . . . 6-12
Audio Processor Equipment Defective or Incorrectly Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Incorrect Transmitter Tuning . . . . . . . . . . . . . . . . . 6-12
Transmitter Operated In FlexPatch™ Mode . . . . . 6-13
viii
Failed RF Amplifier. . . . . . . . . . . . . . . . . . . . . . . .
Loss Of A Big Step . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: Higher than Normal Audio Distortion. . . . .
Failed RF Amplifier(s). . . . . . . . . . . . . . . . . . . . . .
Finding a Missing Step . . . . . . . . . . . . . . . . . . . . .
Transmitter Mistuning . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Into A Bandwidth Restricted Antenna. . . . .
Mistuning Of The Bandpass Tuning Control C101 . . .
Low RF Drive Level To The RF Amps . . . . . . . . . . . .
Additional Tips For Troubleshooting Audio THD. . . .
Consistent Loss of RF Amplifier Modules. . . . . . . . . . . .
Symptom: Consistent Loss of an RF Amp in one Particular Slot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Improper RF Drive. . . . . . . . . . . . . . . . . . . . . . . . .
Improper Drain Phasing. . . . . . . . . . . . . . . . . . . . .
Defective Output Toroid . . . . . . . . . . . . . . . . . . . .
Symptom: Consistent Loss of Modules in Random
Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A to D Phasing Improperly Set . . . . . . . . . . . . . . .
Modulated B- Improperly Set . . . . . . . . . . . . . . . .
Improper VSWR Circuit Operation. . . . . . . . . . . .
Improper Setting Of The Oscillator Sync Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Improper Overload Settings. . . . . . . . . . . . . . . . . .
Improper Air Flow . . . . . . . . . . . . . . . . . . . . . . . . .
Transmitter Mistuning . . . . . . . . . . . . . . . . . . . . . .
Symptom: Excessive Carrier Shift . . . . . . . . . . . . . . . .
Symptom: Apparent poor Efficiency . . . . . . . . . . . . . .
Transmitter Mistuning . . . . . . . . . . . . . . . . . . . . . .
Mistuning Of The Bandpass Tuning Control
C101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low RF Drive Level To The RF Amps . . . . . . . .
Other Troubleshooting Techniques. . . . . . . . . . . . . . . . . .
Handling MOSFET’s. . . . . . . . . . . . . . . . . . . . . . . . . . .
Testing MOSFET’s . . . . . . . . . . . . . . . . . . . . . . . .
Using FlexPatch™ for Bypassing a Failed RF Amp . .
Using FlexPatch™ for Isolating Modulation Encoder/RF Amp Problems . . . . . . . . . . . . . . . . . . . . . . .
Measuring RF Drive Level . . . . . . . . . . . . . . . . . . . . . .
Measuring Steps 18-42 . . . . . . . . . . . . . . . . . . . . .
Measuring Binary RF Amp Drive Amplitude . . .
Measuring Drive Phasing . . . . . . . . . . . . . . . . . . . . . . .
Scope Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Excessive Drive Phase Difference. . . . . . . . . . . . .
Measuring Steps 18-42 . . . . . . . . . . . . . . . . . . . . .
Measuring Binary RF Amp Drive Phasing . . . . . .
RF Amplifier Drain Phasing . . . . . . . . . . . . . . . . . . . . .
Excessive Drive Phase Difference. . . . . . . . . . . . .
Measuring Steps 18-42 . . . . . . . . . . . . . . . . . . . . .
6-18
6-18
6-20
6-20
6-20
6-20
6-21
6-21
6-21
6-21
6-22
6-22
Section VIA
Emergency Operating Procedures
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
What to do if an Overload Occurs . . . . . . . . . . . . . . . . . . .
Power Supply Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crystal Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Predriver Amplifier Failure . . . . . . . . . . . . . . . . . . . . . . . . .
High Voltage Power Supply Overcurrent. . . . . . . . . . . . . .
RF Overdrive or Underdrive . . . . . . . . . . . . . . . . . . . . . . . .
6-1
6-1
6-1
6-1
6-2
6-2
6-2
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-13
6-13
6-13
6-13
6-13
6-15
6-15
6-15
6-15
6-15
6-15
6-15
6-15
6-15
6-15
6-16
6-16
6-16
6-16
6-16
6-16
6-16
6-16
6-16
6-16
6-16
6-17
6-17
6-17
6-17
6-17
6-17
03/16/2009
VSWR Protection and Operation under High VSWR
Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Emergencvy Operating Procedures for Antenna
VSWR Overload. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DX-10 VSWR Protection Circuit Action . . . . . . . . . . . . . .
Possible Causes of VSWR Overloads . . . . . . . . . . . . . . . .
Common causes of Arcing . . . . . . . . . . . . . . . . . . . . . . .
Load Impedance Changes . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Amplifier Failure (Failure of PA Sections) . . . . . . . . .
Power Amplifier Description . . . . . . . . . . . . . . . . . . . . .
Indications of PA RF Amplifier Failure . . . . . . . . . . . . .
Identifying Failed PA RF Amplifiers . . . . . . . . . . . . . . .
Substituting for Failed Power Amplifier Sections . . . . .
6-2
6-2
6-3
6-3
6-3
6-4
6-4
6-4
6-4
6-4
6-5
Section VII
Parts List
Section A
Oscillator (A17)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VSWR Switching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AUTO Switching -004 assembly only . . . . . . . . . . . . . .
Duty Cycle Adjust -004 assembly only . . . . . . . . . . . . .
Circuit Description, -002 assembly. . . . . . . . . . . . . . . . . . .
Supply Voltages and Voltage Regulators . . . . . . . . . . . .
Oscillator Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buffer/Squaring Amplifier. . . . . . . . . . . . . . . . . . . . . . . .
Frequency Divider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normal or Combined Transmitter Operation . . . . . . . . .
Frequency Monitor Output . . . . . . . . . . . . . . . . . . . . . . .
Oscillator Sync. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oscillator Output (Buffer-Driver) . . . . . . . . . . . . . . . . . .
“RF Present” Output . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description, -004 assembly. . . . . . . . . . . . . . . . . . .
Oscillator Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buffer/Squaring Amplifier. . . . . . . . . . . . . . . . . . . . . . . .
Frequency Divider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Internal/External Oscillator and Combined Transmitter Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DUTY CYCLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AUTO/MANUAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MUTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EXT STATUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single Combined Mode . . . . . . . . . . . . . . . . . . . . . .
Frequency Monitor Output . . . . . . . . . . . . . . . . . . . . . . .
VSWR Switching. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Buffer/Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Present Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting -004 assembly . . . . . . . . . . . . . . . . . . . . .
Oscilloscope Waveform Plots . . . . . . . . . . . . . . . . . . . . .
Measure The Power Supplies . . . . . . . . . . . . . . . . . . . . .
Measure the VSWR-H Input . . . . . . . . . . . . . . . . . . . . . .
Measure the RF Output . . . . . . . . . . . . . . . . . . . . . . . . . .
No Signal Present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
03/16/2009
A-1
A-1
A-1
A-1
A-1
A-1
A-1
A-1
A-1
A-1
A-1
A-1
A-2
A-2
A-2
A-2
A-2
A-2
A-2
A-2
A-2
A-3
A-3
A-3
A-3
A-4
A-4
A-4
A-4
A-4
A-4
A-4
A-4
A-4
A-4
A-4
A-4
A-4
A-4
A-5
A-5
Troubleshooting either assembly . . . . . . . . . . . . . . . . . . . . .
Symptom: Oscillator LED on ColorStat™ panel is
Red, transmitter will not operate. . . . . . . . . . . . . . . . . . .
Possible Cause: Power Supplies. . . . . . . . . . . . . . . .
Possible Cause: Oscillator Sync Circuit. . . . . . . . . .
Possible Cause: RF Not Present at TP5. . . . . . . . . .
Symptom: No RF Output, External Oscillator Used. . . .
Possible Cause: RF Input From External Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Cause: External Input Impedance . . . . . . .
Possible Cause: Q3 or U5 faulty . . . . . . . . . . . . . . .
Symptom: Frequency Stability. . . . . . . . . . . . . . . . . . . . .
Possible Cause: Plug P6. . . . . . . . . . . . . . . . . . . . . .
Possible Cause: Crystal Oven Failure . . . . . . . . . . .
Possible Cause: No -15 Vdc Supply . . . . . . . . . . . .
Possible Cause: Defective Crystal . . . . . . . . . . . . . .
Symptom: Output At Incorrect Frequency . . . . . . . . . . .
Possible Cause: Frequency Divider Jumper
Plug P2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Cause: Frequency Divider Fault . . . . . . . .
Symptom: Oscillator LED on ColorStat™ panel is
Red but transmitter operation is normal. . . . . . . . . . . . .
Possible Cause: RF Present circuit. . . . . . . . . . . . . .
Oscillator Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Carrier Detect Adjustments . . . . . . . . . . . . . . . . . . . . . . .
Oscillator Frequency Fine Adjustment . . . . . . . . . . . . . .
Oscillator Sync Adjustment . . . . . . . . . . . . . . . . . . . . . . .
Oscillator Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Installation Steps for HD Radio
ONLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Final Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A-5
A-5
A-5
A-5
A-5
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-6
A-7
A-7
A-7
A-7
Section B
Buffer Amplifier (A16)
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buffer Amplifier Supply Voltage . . . . . . . . . . . . . . . . . .
First RF Amplifier Stage (U1) . . . . . . . . . . . . . . . . . . . . .
Second RF Amplifier Stage (Q1 and Q2) . . . . . . . . . . . .
Third RF Amplifier Stage (Q3 and Q4) . . . . . . . . . . . . .
Output Coupling Network . . . . . . . . . . . . . . . . . . . . . . . .
Buffer Amplifier RF Sense . . . . . . . . . . . . . . . . . . . . . . .
Predriver Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: Buffer Amplifier LED on ColorStat™
panel is Red, transmitter will not operate. . . . . . . . . . . .
Possible Cause: Component failure . . . . . . . . . . . . .
Possible Cause: Coaxial Cable or Connector
Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: Buffer Amplifier LED on ColorStat™
panel is Red, transmitter will operate. . . . . . . . . . . . . . .
B-2
Section C
RF Amplifier
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Amplifier: Basic Theory Of Operation . . . . . . . . . . .
RF Amplifier: Half Quad Configuration . . . . . . . . . . . . .
RF Amplifier: Full Quad Configuration . . . . . . . . . . . . .
C-1
C-1
C-1
C-1
C-1
888-2247-006
WARNING: Disconnect primary power prior to servicing.
B-1
B-1
B-1
B-1
B-1
B-1
B-1
B-1
B-1
B-1
B-1
B-1
B-1
B-2
ix
RF Amplifier Module On/Off Control Circuit. . . . . . . .
RF Transformer Primary Current: Amplifier Off . . . . .
Oscillator Sync Signal. . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LED Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cable Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: Blown Fuse Indicator Illuminated . . . . . . . .
Possible Cause: Shorted MOSFETS. . . . . . . . . . . .
Checking RF Module Operation. . . . . . . . . . . . . . .
C-1
C-3
C-3
C-3
C-3
C-4
C-4
C-4
C-4
C-5
C-5
C-5
C-5
C-6
Section D
Driver Combiner/Motherboard (A14)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Driver Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buffer Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Predriver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Predriver Metering . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver Splitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Amp/Driver RF Sense. . . . . . . . . . . . . . . . . . . . . . . .
RF Driver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver, Section 1 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver, Section 2 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver, Section 3 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver Outputs, Impedance Matching . . . . . . . . . . . . . .
RF Driver Combiner . . . . . . . . . . . . . . . . . . . . . . . .
Current Sample Transformer T8 . . . . . . . . . . . . . . . . . .
Neutralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connectors and Printed Circuit Board Connectors . . . .
Combiner Toroids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver Tuning Components . . . . . . . . . . . . . . . . . . . . . .
Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switch A14S1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replaceable Parts Service. . . . . . . . . . . . . . . . . . . . . . . . . .
D-1
D-1
D-1
D-1
D-1
D-3
D-3
D-3
D-3
D-3
D-3
D-3
D-3
D-3
D-3
D-3
D-4
D-4
D-4
D-4
D-4
D-4
D-4
D-4
D-4
Section E
Driver Supply Regulator (A22)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
+15 Volt Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Control +VDC Reference . . . . . . . . . . . . . . . . . . . . . . . . . E-1
“Open Loop” Reference Voltage . . . . . . . . . . . . . . . E-1
“Closed Loop” Reference Voltage . . . . . . . . . . . . . . E-1
RF Drive Sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Power MOSFET Operation (A Short Review) . . . . . . . . E-1
Regulator Section Circuit Description . . . . . . . . . . . . . . . E-2
DC Amplifier Stage (Q2) . . . . . . . . . . . . . . . . . . . . . . . . . E-2
Series Pass Transistors Q3 and Q4 (For Section D1A
Supply Voltage) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2
Voltage Divider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2
x
Series Pass Transistors Q5 and Q6 (For Section D1B
Supply Voltage) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Voltage Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Metering Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reference Voltage (CONTROL +VDC) . . . . . . . . .
115 Vdc PA Supply Voltage (DRIVER
+VDC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver Current Metering (“DRIVER IDC”) . . . . . .
Driver Amplifier D1 Voltages (DRIVER 1A
+VDC) and (DRIVER 1B +VDC). . . . . . . . . . . . .
Troubleshooting The Driver Supply Regulator . . . . . . . . .
Symptom: Driver Sect D1A +VDC and Sect D1B
+VDC Both High . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Cause: No +15 VDC . . . . . . . . . . . . . . . . .
Possible Cause: Defective U2 . . . . . . . . . . . . . . . . .
Possible Cause: Defective S1 . . . . . . . . . . . . . . . . .
Symptom: One Output Voltage Is +100 To +110
Volts, Other Can Be Adjusted. . . . . . . . . . . . . . . . . . . .
Possible Cause: Shorted MOSFET in a series
regulator section (Q3, Q4, Q5 and Q6) . . . . . . . . .
Symptom: Both Driver Supply Regulator Output
Voltages Are Zero. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Cause: No +115 Vdc . . . . . . . . . . . . . . . . .
Possible Cause: Driver Supply Regulator
component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: One Driver Supply Output Voltage is
Zero, the Other Can Be Adjusted. . . . . . . . . . . . . . . . . .
Possible Cause: Shorted Gate-to-Source
Zener Diode (CR8, CR11, CR12 and CR14) . . . .
Symptom: Section D1B Voltage Increases Before
Section D1A Voltage Reaches +100 Volts. . . . . . . . . .
Possible Causes: Voltage Offset is Too Low . . . . .
Symptom: Open Loop Operation is Correct, Closed
Loop Operation is Faulty. . . . . . . . . . . . . . . . . . . . . . . .
Possible Cause: No RF Sample Voltage . . . . . . . . .
Possible Cause: Shorted Diode in Bridge Rectifier CR1-CR4 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Cause: Defective U2 . . . . . . . . . . . . . . . . .
Section F
RF Multimeter (A23)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Metering Driver Section Parameters. . . . . . . . . . . . . . . .
Multimeter Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section G
RF Combiners:
Binary Combiner/Motherboard (A18)
and Main Combiner/Motherboards (A19, A20)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Power Combiner . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Combiner Output Steps . . . . . . . . . . . . . . . . . . . . . . . . . .
Main Combiner/Motherboards (A19, A20) . . . . . . . . . .
DC Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RF Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Encoded Audio (Module ON/OFF Control
Signals) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Binary Combiner/Motherboard (A18) . . . . . . . . . . . . . .
Binary Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
888-2247-006
WARNING: Disconnect primary power prior to servicing.
E-2
E-2
E-3
E-3
E-3
E-3
E-3
E-3
E-3
E-3
E-4
E-4
E-4
E-4
E-4
E-4
E-4
E-4
E-4
E-4
E-4
E-4
E-4
E-4
E-4
F-1
F-1
F-1
F-1
G-1
G-1
G-1
G-1
G-2
G-2
G-2
G-2
G-2
G-2
03/16/2009
DC Supply Voltages . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Components . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section H
Output Sample Board (A26) and
Output Monitor (A27)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Sample Board . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Voltage Samples. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Phase Angle Detector, Theory Of Operation . . . . .
Antenna VSWR Phase Angle Detector. . . . . . . . . .
Bandpass Filter VSWR Phase Angle Detector . . . .
“Phase Angle Detector Null” Meter Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VSWR Trip Circuits . . . . . . . . . . . . . . . . . . . . . . . .
“VSWR Trip” Logic . . . . . . . . . . . . . . . . . . . . . . . .
AND Gate U5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Monostable Multivibrators. . . . . . . . . . . . . . . . . . . .
Directional Coupler Circuit Description . . . . . . . . .
Detected Audio. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulation Monitor Sample . . . . . . . . . . . . . . . . . .
+5 VDC And -5 VDC Regulators . . . . . . . . . . . . . .
Section J
Analog Input Board (A35)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Signal Path Through the Analog Input Board . . . . . . . . .
Audio Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bessel Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting an Audio Input Connector (J1, J2
or J3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Balanced Audio Input Stage (U6, U9) . . . . . . . . . . . . . . .
“Instrumentation Amplifier” Operation. . . . . . . . . . .
Buffer Amplifer (U7) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maximum Power Adjust (U7, R27) . . . . . . . . . . . . . . . . .
“Power Supply Sample” Circuit (U10, U12B). . . . . . . . .
“Analog Divider” U10 . . . . . . . . . . . . . . . . . . . . . . . .
Power Supply Sample, Circuit Description. . . . . . . .
Protection Circuit: R33, R34, CR9, and Associated Components . . . . . . . . . . . . . . . . . . . . . . . . . .
Digitally Controlled Potentiometer (U8) and Output
Amplifier (U11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BCD Logic Input to Digitally Controlled Attenuator U8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog Input Board,, BCD Power Control Inputs . . . . . .
Power Control Latches, U17-U18. . . . . . . . . . . . . . . . . . .
“Clock” Input (“Data Strobe” or “Auto
Strobe” Pulses) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Reset” Input (Data Clear). . . . . . . . . . . . . . . . . . . . .
TTL to CMOS Level Shifters (U14, U16) . . . . . . . .
Analog Buffer Stage (U4A). . . . . . . . . . . . . . . . . . . .
PA Turn On/Turn Off Circuit (U13-2, Q1, Q7, U134, Q2, Q8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Differential Amplifier/Inverter U4B . . . . . . . . . . . . . . . . .
03/16/2009
G-2
G-2
G-2
G-2
G-3
H-1
H-1
H-1
H-1
H-1
H-1
H-1
H-2
H-2
H-2
H-2
H-3
H-3
H-3
H-3
H-3
H-3
H-4
J-1
J-1
J-1
J-1
J-1
J-1
J-2
J-2
J-2
J-2
J-2
J-2
J-2
J-3
J-3
J-3
J-3
J-3
J-3
J-3
J-3
J-3
J-4
J-4
“Dither” Signal: Function . . . . . . . . . . . . . . . . . . . . . . . .
Dither Oscillator (U3, U19, and U5A) . . . . . . . . . . . . . .
Oscillator Circuit Description. . . . . . . . . . . . . . . . . .
Square Wave Generator U19 . . . . . . . . . . . . . . . . . .
Integrator U3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dither Oscillator Circuit Operation . . . . . . . . . . . . .
“A/D Big Step Sync” Input to Dither Oscillator. . . . . . .
-(Audio + DC) Sample to DC Regulator. . . . . . . . . . . . .
(Audio + DC) Sample Circuit Description . . . . . . .
Analog Input Board Power Supplies . . . . . . . . . . . . . . . .
“Dither”: A Description . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Printed Circuit Board Maintenance Procedures . . . . . . .
Replacing CMOS Devices . . . . . . . . . . . . . . . . . . . . . . . .
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Audio Gain Adjust,” R15 . . . . . . . . . . . . . . . . . . . .
Maximum Power Adjustment (R27, “MAX
PWR ADJ”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dither Frequency Adjust, R41 . . . . . . . . . . . . . . . . .
Dither Level Adjust, R43 . . . . . . . . . . . . . . . . . . . . .
“Offset” Adjust, R84 . . . . . . . . . . . . . . . . . . . . . . . .
“Gain” Adjust, R85. . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting the Analog Input Board . . . . . . . . . . . . . .
Symptom. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Causes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
U8, U10, or U11 faulty . . . . . . . . . . . . . . . . . . . . . .
Digital Control Signal at U8 is Zero . . . . . . . . . . . .
Power Increases or Decreases in Steps, Not
Continuously . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section K
Analog To Digital Converter (A34)
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Converting a PA Sample to the A/D ENCODE Pulse
(T1, U29, Q9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Frequency Divider (U29, Q9 ). . . . . . . . . . . . . . . . . . . . .
ENCODE Signal Pulse Width (Q9). . . . . . . . . . . . . . . . .
Analog to Digital Converter Circuit . . . . . . . . . . . . . . . .
Analog Input Circuit (U28) . . . . . . . . . . . . . . . . . . .
Analog to Digital Converter (U1, DL1). . . . . . . . . .
Digital Data Latches (U3, U4, DL3) . . . . . . . . . . . .
Error Detecting Circuits . . . . . . . . . . . . . . . . . . . . . . . . . .
One-Shot Operation (U13, U14) . . . . . . . . . . . . . . . . . . .
Power Up Reset (C41, R16, U12-F) . . . . . . . . . . . .
Clock Error Detection Circuit (U14-A) . . . . . . . . . .
A/D Converter Monitor Circuit (U13-A). . . . . . . . .
Conversion Error Indicator (U14-B, U11,
DS1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Big-Step Sync Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . .
Big Step Sync Circuit D/A Converter (U22). . . . . .
Amplifier Stage (U24, U25, U26) . . . . . . . . . . . . . .
Differentiator and Buffer (U27) . . . . . . . . . . . . . . . .
Reconstructed Audio Circuit . . . . . . . . . . . . . . . . . . . . . .
Reconstructed Audio Circuit D/A converter
(U8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reconstruction Filter (L1, L2, L3, C47, C48,
C49) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Grounds A, AA, B and Chassis . . . . . . . . . . . . . . . .
888-2247-006
WARNING: Disconnect primary power prior to servicing.
J-4
J-4
J-4
J-4
J-4
J-4
J-5
J-5
J-5
J-5
J-5
J-5
J-5
J-5
J-6
J-6
J-6
J-6
J-6
J-6
J-6
J-6
J-6
J-6
J-6
J-6
J-7
K-1
K-1
K-1
K-1
K-1
K-1
K-1
K-1
K-2
K-2
K-2
K-2
K-2
K-2
K-3
K-3
K-3
K-3
K-3
K-3
K-3
K-3
K-3
K-3
xi
Voltage Regulators (U2, U16, U18, U19,
U20, U21, Q1) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Printed Circuit board Maintenance. . . . . . . . . . . . . . . . .
Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sync Sample Phasing (S1) . . . . . . . . . . . . . . . . . . .
Clock Pulse Width Adjustment (R78) . . . . . . . . . .
Digital to Analog Converter Bit Selection
(S2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: ColorStat™ panel CONVERSION ERROR Indicator is RED, transmitter operates normally. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: ColorStat™ panel CONVERSION ERROR indicator is RED, transmitter can be turned
ON. No RF out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check Logic Level at TP8. . . . . . . . . . . . . . . . . . . .
CLK ERROR-L: No signal at TP6 . . . . . . . . . . . . .
CLK ERROR-L: Signal present at TP6 . . . . . . . . .
EOC-L FAULT . . . . . . . . . . . . . . . . . . . . . . . . . . . .
POWER UP RESET-L FAULT . . . . . . . . . . . . . . .
Technical Assistance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replaceable Parts Service. . . . . . . . . . . . . . . . . . . . . . . . . .
K-4
K-4
K-4
K-4
K-4
K-4
K-4
K-4
K-4
K-4
K-4
K-4
K-4
K-5
K-5
K-5
K-5
Section L
Modulation Encoder (A36)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-1
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-1
Modulation Encoding: Explanation and Example . . . . . . L-1
Modulation Encoding: Read Only Memories . . . . . . . . . L-1
Circuit Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-1
SUPPLY VOLTAGES AND POWER SUPPLY INPUTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-1
+5 VOLT SUPPLY . . . . . . . . . . . . . . . . . . . . . . . . . . L-1
Modulated B-. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-1
Circuit Descriptions: Digital Audio Data Circuits . . . . . . L-1
Data Input Latches (U49, U50) . . . . . . . . . . . . . . . . . . . . L-1
“Binary Step” Digital Audio Circuits (U31,
U60-U61, U1, U2, U62) . . . . . . . . . . . . . . . . . . . . . L-1
“Big Step” Digital Audio Circuits PA Module TurnOn/Turn-Off Data Circuits . . . . . . . . . . . . . . . . . . . . . . . L-2
ROM’S (Read Only Memories) AND
LATCHES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-2
Patch Plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-2
Inverter/Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-2
Inverter/Driver Input . . . . . . . . . . . . . . . . . . . . . . . . . L-2
Inverter/Driver Output. . . . . . . . . . . . . . . . . . . . . . . . L-2
Modulated B-. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-2
Data Strobe Signal Circuit: Data Latch “Clock” Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-3
PA Turn-Off (“Data Clear”) Input . . . . . . . . . . . . . . . . . . L-3
“Clip” Function (“Clip-H” and “Clip-L” Signals). . . . . . L-3
“Clip” Function: What Happens if the Clip-L
Patch (P15) is not Connected?. . . . . . . . . . . . . . . . . L-3
“Clip” Circuit: Description . . . . . . . . . . . . . . . . . . . . . . . . L-4
Single RF Amp Momentary Test: Pushbutton Switch
S2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-4
RF Amplifier Cable Connector Interlock Circuit . . . . . . L-4
Cable Interlock, Description . . . . . . . . . . . . . . . . . . . L-4
Cable Interlock Indicators. . . . . . . . . . . . . . . . . . . . . . . . . L-4
xii
“INTLK OFF” (“ERROR”) Indication . . . . . . . . . .
“INTLK ON” Indication . . . . . . . . . . . . . . . . . . . . .
“PA Turn Off” Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . .
PA Turn-Off Indicators . . . . . . . . . . . . . . . . . . . . . .
Power-Up Reset (U57D, U57B) . . . . . . . . . . . . . . . . . . .
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Printed Circuit Board Maintenance. . . . . . . . . . . . . . . . .
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“CLIP” Patch P15.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting the Modulation Encoder Board . . . . . . . .
Symptom: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Suggestions . . . . . . . . . . . . . . . . . . . . .
Symptom: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Suggestions . . . . . . . . . . . . . . . . . . . . .
Symptom: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Causes:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Troubleshooting Suggestions:. . . . . . . . . . . .
Section M
DC Regulator (A30)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Grounds on the DC Regulator Board . . . . . . . . .
UC3834 Integrated Circuit Linear Regulator . . . . . . . . .
OTHER SUPPLIES USING THE UC3834 . . . . . . . . . .
Linear Regulator IC Description . . . . . . . . . . . . . . . . . . .
Regulator Circuit Operation . . . . . . . . . . . . . . . . . . . . . .
Regulator IC: Fault Logic . . . . . . . . . . . . . . . . . . . .
Crowbar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regulator IC Thermal Shutdown. . . . . . . . . . . . . . .
+5 Volt Regulated Supply (DC Regulator Board) . . . . .
Basic Regulator Circuit (U1, Q1) . . . . . . . . . . . . . .
Turn-On Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crowbar (Q2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Other Regulator Circuit Components . . . . . . . . . . .
Other Positive Regulated Supplies . . . . . . . . . . . . . . . . .
Modulated B- Supply . . . . . . . . . . . . . . . . . . . . . . . . . . .
Approximate Modulated B- Supply Output
Voltages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulated B- Supply: Circuit Description . . . . . . . . . . .
-(Audio + DC) Input . . . . . . . . . . . . . . . . . . . . . . . .
Modulated B- Supply Regulator Circuit . . . . . . . . .
Other Negative Regulated Supplies . . . . . . . . . . . . . . . .
Contactor Drivers (U2, Q3, U4 and Q6) . . . . . . . . . . . .
High Voltage Supply Contactors. . . . . . . . . . . . . . .
AC Supply for K1, K2. . . . . . . . . . . . . . . . . . . . . . .
Contactor Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interlock Status Circuit . . . . . . . . . . . . . . . . . . . . . . . . . .
External Interlock Status . . . . . . . . . . . . . . . . . . . . .
Door Interlock Status . . . . . . . . . . . . . . . . . . . . . . . .
Interlock String DC Status. . . . . . . . . . . . . . . . . . . .
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Printed Circuit Board Maintenance. . . . . . . . . . . . . . . . .
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regulated Power Supply Troubleshooting . . . . . . . . . . . . .
Fuse in Unregulated Input Line Open (F1 or F3 on
DC Regulator Board) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Causes:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Temporary Overvoltage or Transient . . . . . . . . . . .
888-2247-006
WARNING: Disconnect primary power prior to servicing.
L-5
L-5
L-5
L-5
L-7
L-7
L-7
L-7
L-7
L-7
L-7
L-7
L-7
L-7
L-7
L-7
L-7
L-7
M-1
M-1
M-1
M-1
M-1
M-1
M-2
M-2
M-2
M-2
M-2
M-2
M-3
M-3
M-3
M-3
M-3
M-3
M-3
M-3
M-4
M-4
M-5
M-5
M-5
M-5
M-5
M-5
M-5
M-5
M-5
M-5
M-5
M-5
M-5
M-5
M-5
03/16/2009
Shorted Transistor or Diode . . . . . . . . . . . . . . . . . .
Shorted “Crowbar” Triac . . . . . . . . . . . . . . . . . . . . .
Shorted Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
No Output Voltage or Output Voltage Less than
about -2 Volts from Modulated B- Supply . . . . . . . . . .
Possible Causes:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modulated B- Supply Controls Not Adjusted
Properly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
No -(Audio + DC) Signal . . . . . . . . . . . . . . . . . . . .
Section N
External Interface (A28)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Schematic Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Outputs (Type A) . . . . . . . . . . . . . . . . . . . . . . . . .
Status output Protection . . . . . . . . . . . . . . . . . . . . . .
Control Inputs (Type B) . . . . . . . . . . . . . . . . . . . . . . . . .
Opto-Isolator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Input Requirements. . . . . . . . . . . . . . . . . . .
Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Monitor Voltage Outputs. . . . . . . . . . . . . . . . . . . . . . . . .
Voltage-Divider Outputs (Type C or Type D) . . . .
Operational Amplifier Buffered Outputs
(Type E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . .
External Interlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Combiner Interconnect . . . . . . . . . . . . . . . . . . . . . . . . . .
PA Turn-Off and Off Control . . . . . . . . . . . . . . . . . . . . .
PA Turn-Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Off Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Interface Power Supplies . . . . . . . . . . . . . . . . .
DC Voltages Supplied to the Board . . . . . . . . . . . .
Zener Diode Regulated +15 and -15 Volts . . . . . . .
Three-Terminal Regulators . . . . . . . . . . . . . . . . . . .
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: No Remote Control Inputs Operate . . . . . . .
Supply voltage for external inputs missing. . . . . . .
Remote Control Equipment Fault . . . . . . . . . . . . . .
Symptom: Some Remote Control Inputs Operate,
But One or More Do Not. . . . . . . . . . . . . . . . . . . . . . . .
Faulty Opto-Isolator, Faulty Transmitter
Logic, or Faulty Remote Control Equipment . . . .
Additional Notes: . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: No Remote Status Outputs Operate . . . . . . .
No Supply Voltage For Status Circuits. . . . . . . . . .
Symptom: Some Status Outputs Operate . . . . . . . . . . . .
Problem In Transmitter Fault And Overload
Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Problem Is Outside The Transmitter . . . . . . . . . . . .
Symptom: One or More Remote Status Indications
Remain “ON” Even Though the Transmitter’s
Status Indication is Off (or Green) . . . . . . . . . . . . . . . .
Problem In Transmitter Fault And Overload
Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shorted Transistor On Fault And Overload
Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
03/16/2009
M-5
M-6
M-6
M-6
M-6
M-6
M-6
N-1
N-1
N-1
N-1
N-1
N-1
N-2
N-2
N-2
N-2
N-2
N-2
N-2
N-4
N-4
N-4
N-4
N-4
N-4
N-4
N-4
N-4
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-5
N-6
N-6
Symptom: No Monitor Outputs (Analog Signal Outputs) Operate, or All are Seriously Incorrect . . . . . . . . . N-6
No +15 Volts, or -15 Volts, or Both On External Interface Board. . . . . . . . . . . . . . . . . . . . . . . . N-6
Section P
Controller (A38)
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmitter Turn-On/Turn-Off Control Logic . . . . . . . . . .
Basic Turn-On Sequence Requirements . . . . . . . . .
Inputs to Turn-On/Turn-Off Control Logic. . . . . . . . . . .
Outputs From Turn-On/Turn-Off Control Logic . . . . . .
Turn-On/Turn-Off Logic Flow . . . . . . . . . . . . . . . . . . . . . .
Transmitter Turn-On, From “OFF” Condition . . . . . . . .
Turn-On Sequence: . . . . . . . . . . . . . . . . . . . . . . . . . .
Faults During the Turn-On Sequence:. . . . . . . . . . . . . . .
Contactor K1 Does Not Energize. . . . . . . . . . . . . . .
Contactor K2 Does Not Energize. . . . . . . . . . . . . . .
Turn-On/Turn-Off Circuit Logic States, When the
Transmitter Is ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Level Change, with the Transmitter Already
ON: Turn-On/Turn-Off Logic Flow . . . . . . . . . . . . . . . .
Turn-On/Turn-Off Circuit Action . . . . . . . . . . . . . .
Transmitter Turn-Off: Turn-On/Turn-Off Control
Logic Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“OFF” Command During the Turn-On Sequence. . . . . .
Faults During the Turn-On Sequence: Type 1 or
Type 2 Fault, or OFF Command . . . . . . . . . . . . . . . . . .
Controller Board Supply Fault During the Turn-On
Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“BROWN-OUT” or Controller Board Supply Fault
During Normal Operation . . . . . . . . . . . . . . . . . . . . . . . .
Brown-Out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Type 1 or Type 2 Fault, When the Transmitter is ON . .
Type 2 Fault: Recycle Transmitter OFF then ON . . . . .
AC Power Recycle (Recycle “ON” After Power Failure). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Generate Turn-On Request: . . . . . . . . . . . . . . . . . . .
Inhibit Fault-Generated “OFF” Command. . . . . . . .
Summary: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Turn-On/Turn-Off Control Logic: Circuit Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“K1 Turn-On One-Shot” (Monostable U50A) . . . . . . . .
Trigger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inhibit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
One-Shot Trigger and Operation During Transmitter
Turn-On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logic Levels at U50A Inputs and Outputs . . . . . . .
Contact De-Bounce and Logic Level Converter Circuits (Q5C-U59C, Q5D-U59B). . . . . . . . . . . . . . . . . . . .
Delay Circuits: Description . . . . . . . . . . . . . . . . . . . . . . .
0.3 Second Delay Timer: Delay on/Fast Off
(U59A, U59F, R34, C103, R115, CR15) . . . . . . . .
0.8 Second Delay Timer (R33, C104, U57A,
U57B). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
50 Millisecond Delay (R32, C105, U59E) . . . . . . .
“PA Off” and “Overdrive Inhibit” Gate U53B . . . .
“PA Turn-Off” (U52A, U53B, and S5). . . . . . . . . . . . . .
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-1
P-1
P-1
P-1
P-1
P-2
P-2
P-2
P-2
P-3
P-3
P-3
P-4
P-4
P-4
P-4
P-5
P-5
P-5
P-5
P-5
P-5
P-5
P-6
P-6
P-6
P-6
P-7
P-7
P-7
P-7
P-7
P-7
P-7
P-8
P-8
P-8
P-8
P-8
P-8
P-8
xiii
Gate U52A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-8
“PA Off” Gate, U53B . . . . . . . . . . . . . . . . . . . . . . . . P-9
Power Control Logic: Principles of Operation . . . . . . . . . . P-9
“Command” Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-10
Other Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-10
Power Control Section: Logic Outputs . . . . . . . . . . . . . P-10
Logic Flow in the Power Contol Section. . . . . . . . . . . . P-10
Power Control Logic: Circuit Descriptions . . . . . . . . . . . . P-11
Command Input Circuits: Description . . . . . . . . . . . . . . P-11
“Local Control” Inputs . . . . . . . . . . . . . . . . . . . . . . P-11
“Extended Control” Inputs . . . . . . . . . . . . . . . . . . . P-12
“Fault-Induced” Commands, Command Inputs From Fault and Overload Circuits. . . . . . . . . P-12
Inhibit Gates (U46A, U46B, U46C). . . . . . . . . . . . . . . . P-12
Switch De-Bounce (U37) . . . . . . . . . . . . . . . . . . . . . . . . P-12
Why is a De-bounce Circuit Used? . . . . . . . . . . . . P-13
Internal “Clock” Oscillator . . . . . . . . . . . . . . . . . . . P-13
“Contact Bounce Eliminator” Operation . . . . . . . . P-13
Priority Encode/Decode . . . . . . . . . . . . . . . . . . . . . . . . . P-13
Priority Encoder and Decoder Circuit Description . . . . P-13
Encoder and Decoder Operation . . . . . . . . . . . . . . . . . . P-13
Encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-13
Inverters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-13
Decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-13
Decoder: Inhibit Decode . . . . . . . . . . . . . . . . . . . . . P-13
Inhibit Decode One-Shot, U50B. . . . . . . . . . . . . . . P-15
Decoder U40 Outputs . . . . . . . . . . . . . . . . . . . . . . . P-15
Inverters (U41A through F) . . . . . . . . . . . . . . . . . . P-15
“Power Level Change” Pulse . . . . . . . . . . . . . . . . . . . . . P-15
Inhibit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-15
Data Strobe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-15
“Power Level Change Pulse” Circuit Description . . . . . P-15
Input “OR” Gate (U49B) . . . . . . . . . . . . . . . . . . . . P-15
Delay (U51A, U51B, R128, C128) . . . . . . . . . . . . P-15
“Power Level Change” Pulse Generator . . . . . . . . P-16
Transistor Q4D: Fast “OFF” Command. . . . . . . . . P-16
“Power Level Change” Inhibit . . . . . . . . . . . . . . . . P-16
Power Level Latch (U42) . . . . . . . . . . . . . . . . . . . . . . . . P-16
Power Level Latch “CLEAR” . . . . . . . . . . . . . . . . P-16
Latched “OFF” Command . . . . . . . . . . . . . . . . . . . . . . . P-16
Power Level Latch Outputs . . . . . . . . . . . . . . . . . . . . . . P-16
Inhibit Gates (“AND” Gates U43A, U43B And
U43C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-16
“INHIBIT K2-L” . . . . . . . . . . . . . . . . . . . . . . . . . . . P-17
Turn-On Request Gate (U53) and Inverter (U51) . . . . . P-17
Up-Down Counters: Setting and Storing Digital
Power Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-17
Up-Down Counters . . . . . . . . . . . . . . . . . . . . . . . . . P-17
Counter Control Gates. . . . . . . . . . . . . . . . . . . . . . . P-17
Inhibit Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-17
Digital Power Control Signals . . . . . . . . . . . . . . . . P-17
Up-Down Counters (U7-U9, U19-U21, and U31U33) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-17
“CARRY” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-17
“BORROW” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-18
Up-Down Counter “CLOCK”. . . . . . . . . . . . . . . . . P-18
Clear. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-18
Power Control Data “MEMORY” . . . . . . . . . . . . . P-18
Low Power Mode, “PRESET” Function
(U44F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-18
xiv
Up-Down Counter Control Gates (U63, U64, U65,
U68) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gate Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example: High Power Mode, Count “UP”
Control Gate (U63A) . . . . . . . . . . . . . . . . . . . . . .
Example: High Power Mode, Count
“DOWN” Control Gate (U63B). . . . . . . . . . . . . .
Data Strobe “AND” Gates (U68A, U68D, U68C,
U45A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Up-Down Counter “INHIBIT” Circuits . . . . . . . . . . . .
Hi-Lo, Med-Lo, and Lo-Lo Inbibit . . . . . . . . . . . .
Hi-Hi, Med-Hi, and Low-Hi Inhibit . . . . . . . . . . .
Up-Down Counter Outputs . . . . . . . . . . . . . . . . . .
Multiplex and Output Buffers for BCD Power Data
(U1-U3, U13-U15, and U25-U27). . . . . . . . . . . . . . . .
Tri-State Buffers. . . . . . . . . . . . . . . . . . . . . . . . . . .
Tri-State Buffers: “C” Input . . . . . . . . . . . . . . . . .
BCD Readouts (“Not Used”) . . . . . . . . . . . . . . . . . . . .
Other “Power Control Section” Circuits. . . . . . . . . . . .
“Data Strobe” Output and Delay (U45A,
U57F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Nand” Gate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pulse Delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Control Status Indicator Drivers (U47, U48) . .
Logic Buffers . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drivers for Front Panel Indicator Lamps . . . . . . .
Clock Inhibit Gate (U68B).. . . . . . . . . . . . . . . . . . . . . .
Clock Frequency Divider and Delay (U70, U71,
U74E, U74B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CLOCK PULSE DELAY. . . . . . . . . . . . . . . . . . . .
“Interlock Status” Fault Logic . . . . . . . . . . . . . . . . . . . . .
Status Indications . . . . . . . . . . . . . . . . . . . . . . . . . .
Interlock Diagrams. . . . . . . . . . . . . . . . . . . . . . . . .
Interlock Status Logic: Inputs . . . . . . . . . . . . . . . . . . . .
Door Interlock Input . . . . . . . . . . . . . . . . . . . . . . .
Door Interlock Circuit . . . . . . . . . . . . . . . . . . . . . .
Door Interlock Relay K4 . . . . . . . . . . . . . . . . . . . .
External Interlock Input . . . . . . . . . . . . . . . . . . . . .
External Interlock Circuit, and Relay K3 . . . . . . .
“Interlock String” Input . . . . . . . . . . . . . . . . . . . . .
“Interlock String” Circuit. . . . . . . . . . . . . . . . . . . .
Interlock Status Logic: Outputs. . . . . . . . . . . . . . . . . . .
“Interlock Status” Logic: Basic Circuit Description . .
Delay Circuit: Function . . . . . . . . . . . . . . . . . . . . .
Pulse Stretcher: Function . . . . . . . . . . . . . . . . . . . .
“NOR” Gate (U73A or U73B): Function . . . . . . .
Interlock Status Circuit: “No Interlock Fault” . . .
Interlock Status Circuit: If a Fault Occurs . . . . . .
Interlock Status Circuit: When a Fault
“Clears” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Interlock Status Logic, Input Circuits . . . . . . . . . . . . . .
“Door Interlock” and “External Interlock”
Status Circuit Inputs . . . . . . . . . . . . . . . . . . . . . . .
“Door Interlock” Inputs . . . . . . . . . . . . . . . . . . . . .
“External Interlock” Input . . . . . . . . . . . . . . . . . . .
“Interlock String” Input . . . . . . . . . . . . . . . . . . . . .
Transistor “Logic Circuits” . . . . . . . . . . . . . . . . . .
“Inhibit” Transistor Q12B . . . . . . . . . . . . . . . . . . .
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-18
P-18
P-18
P-19
P-19
P-19
P-19
P-19
P-19
P-19
P-20
P-20
P-20
P-20
P-20
P-20
P-20
P-20
P-22
P-22
P-22
P-22
P-22
P-22
P-22
P-22
P-22
P-23
P-23
P-23
P-23
P-23
P-23
P-23
P-23
P-23
P-25
P-25
P-25
P-25
P-25
P-25
P-25
P-25
P-26
P-26
P-26
P-26
P-26
P-26
03/16/2009
“Interlock Fault” Logic Output (for any Interlock
Fault). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Type 1 Fault Gate, U58C . . . . . . . . . . . . . . . . . . . . . . .
+5B Reset Circuit (U66) . . . . . . . . . . . . . . . . . . . . . . . . . .
+5B Reset-L Output (U66A) . . . . . . . . . . . . . . . . .
+5B Reset-H Output (U66C). . . . . . . . . . . . . . . . .
Power Supplies (+5V, +15V and -15 V Regulators. . . . .
DC Regulator Circuits . . . . . . . . . . . . . . . . . . . . . . . . . .
+5B (Backup) Supply . . . . . . . . . . . . . . . . . . . . . . . . . .
Energy Storage Capacitor . . . . . . . . . . . . . . . . . . .
BACK-UP SUPPLY CAPACITOR
CHARGE TIME . . . . . . . . . . . . . . . . . . . . . . . . . .
Battery Back-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Do Not Use Rechargeable Batteries, such as
NiCad Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing Batteries (if used) . . . . . . . . . . . . . . . . .
“Supply Fault” Circuits on the Controller Board . . . . . . .
Regulator “Fault Alerts”: Supply Fault Circuit Inputs .
“Regulator Fault Summary” Indicator, DS1. . . . . . . . .
“Fast On-Slow Off” Delay Circuit (U67A, U67B) . . .
Delay Circuit Function. . . . . . . . . . . . . . . . . . . . . .
“Fast On” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Slow Off” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Data Clear” Logic Buffer . . . . . . . . . . . . . . . . . . . . . .
Supply Fault Logic Outputs . . . . . . . . . . . . . . . . . . . . .
“Data Clear” (from Buffer U67F-U67D) . . . . . . .
Supply Fault - L (from U67B) . . . . . . . . . . . . . . .
Analog Monitor (Metering) Buffer/Drivers (U54,
U55, U56) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forward and Reflected Power Metering
(U54A through U54D) . . . . . . . . . . . . . . . . . . . . .
VSWR Detector Null Metering (U55A
through U55D) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Volts Metering (U56C) . . . . . . . . . . . . . . .
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Printed Circuit Board Maintenance. . . . . . . . . . . . . . . .
CMOS Integrated Circuits. . . . . . . . . . . . . . . . . . . . . . .
Replacing Logic Integrated Circuits . . . . . . . . . . . . . . .
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section Q
LED Board (A32)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . . . .
DX-10 Transmitter Fault Types . . . . . . . . . . . . . . . . . . . . .
Type 1 Fault - Turns Transmitter Off. . . . . . . . . . . . . . .
Type 1 Fault Indications . . . . . . . . . . . . . . . . . . . . .
Type 2 Fault - Recycles Transmitter OFF/ON One
Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repeated Type 2 Faults become Type 1
Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Type 2 Fault Indications . . . . . . . . . . . . . . . . . . . . .
Type 3 Faults - Lowers Transmitter Power . . . . . . . . . .
VSWR Trip and Type 3 Fault Indications . . . . . . .
Type 4 Faults - Apply PA Turn-Off . . . . . . . . . . . . . . . .
Type 4 Fault Indications . . . . . . . . . . . . . . . . . . . . .
Type 5 Fault - Clear Modulation Data . . . . . . . . . . . . . .
Type 5 Fault (Conversion Error) Indication . . . . . .
Type 6 Faults - Display Fault Only (Envelope Error) . .
Type 6 Fault (Envelope Error) Indication. . . . . . . .
03/16/2009
P-27
P-27
P-27
P-27
P-27
P-27
P-27
P-27
P-27
P-27
P-28
P-28
P-28
P-28
P-28
P-29
P-29
P-29
P-29
P-29
P-29
P-29
P-29
P-29
P-29
P-29
P-29
P-30
P-30
P-30
P-30
P-30
P-30
Q-1
Q-1
Q-1
Q-1
Q-1
Q-1
Q-1
Q-1
Q-1
Q-1
Q-4
Q-4
Q-4
Q-4
Q-4
Q-4
Type 7 Faults - Transmitter Inhibited From Turn-On . . Q-4
DX-10 Fault Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-4
LED Board (A32), Block Diagram Description . . . . . . . . . Q-5
Type 1 Faults: Block Diagram Description. . . . . . . . . . . Q-5
Type 2 Faults: Block Diagram Description. . . . . . . . . . . Q-5
Type 3 Faults: Block Diagram Description. . . . . . . . . . . Q-5
VSWR Self-Test Circuit: Block Diagram Description . . Q-6
Type 4 Faults: Block Diagram Description. . . . . . . . . . . Q-6
Type 5 Faults AND Type 6 Faults: Block Diagram
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-6
RF Sense Circuits: Block Diagram Description . . . . . . . Q-6
Reser Circuit: Block Diagram Description . . . . . . . . . . . Q-6
Reset Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-6
Reset Commands:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-7
Other Reset Circuit Inputs: . . . . . . . . . . . . . . . . . . . . . . . Q-7
Reset Circuit Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-7
“Reset A” and “Reset B” Operation . . . . . . . . . . . . . . . . . . Q-7
Latch Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-7
Retrigger Gate Operation . . . . . . . . . . . . . . . . . . . . . Q-7
Reset Circuit Description . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-8
“Reset” Pushbutton Switch . . . . . . . . . . . . . . . . . . . . . . . Q-8
Switch De-Bounce . . . . . . . . . . . . . . . . . . . . . . . . . . Q-8
Inhibit Gate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-8
Reset A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-8
Reset B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-8
“Latched” Fault Status Indicator Circuits . . . . . . . . . . . . Q-9
“Fault” Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-9
“Normal” Indication (No Fault) . . . . . . . . . . . . . . . . Q-9
Resetting Fault Indications . . . . . . . . . . . . . . . . . . . . Q-9
Exceptions: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-9
Type 1 Fault Circuits: Principles of Operation . . . . . . . . . . Q-9
Type 1 Fault Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-10
Pulse Stretcher U64B . . . . . . . . . . . . . . . . . . . . . . . Q-10
Air Flow Fault Sensing . . . . . . . . . . . . . . . . . . . . . . . . . Q-10
Air Flow Sensing Unit S7 . . . . . . . . . . . . . . . . . . . Q-10
“Air Flow Fault” Logic . . . . . . . . . . . . . . . . . . . . . . . . . Q-10
“Anti Flutter” Delay, U12A . . . . . . . . . . . . . . . . . . Q-11
“Air Interlock” Status Indicator Circuit . . . . . . . . . Q-11
High Voltage Supply Protection Circuit . . . . . . . . . . . . Q-12
High Voltage Supply “Overvoltage” Circuit. . . . . . . . . Q-13
“Cable Interlocks” Circuit . . . . . . . . . . . . . . . . . . . . . . . Q-13
Output monitor +5V and -5V Faults, and DC Regulator +5V and B- Faults . . . . . . . . . . . . . . . . . . . . . . . . . . Q-14
“Door Interlock” and “External Interlock” Status Indication Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-14
Type 2 Fault Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-14
Type 2 Fault Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q-14
Type 2 Fault Status Indicators . . . . . . . . . . . . . . . . . . . . Q-14
Circuit Desriptions: Type 2 Fault Detection Circuits . . Q-14
RF Underdrive and Overdrive Fault Detection . . . . . . . Q-14
RF Drive Sample Input Circuit (T1 and Associated Components) . . . . . . . . . . . . . . . . . . . . . . . . Q-14
RF Detectors and Voltage Comparators . . . . . . . . Q-14
RF Overdrive Fault Detector (U28B) . . . . . . . . . . Q-14
RF Underdrive Fault Detector (U29C) . . . . . . . . . Q-16
Comparator Voltage Ramp, “Underdrive Inhibit A”, and “Underdrive Inhibit B” . . . . . . . . . . Q-16
“Underdrive Inhibit A” and “Underdrive Inhibit B” Logic Signals . . . . . . . . . . . . . . . . . . . . . . Q-16
Underdrive Reference Voltage Ramp . . . . . . . . . . Q-16
888-2247-006
WARNING: Disconnect primary power prior to servicing.
xv
“Underdrive Inhibit A” and Inhibit Gate
U29C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible Causes of Underdrive During TurnOn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Current Overload . . . . . . . . . . . . . . . . . . . . . . .
Peak Current Overload . . . . . . . . . . . . . . . . . . . . .
Average Current Overload and Remote Supply Current Metering Output . . . . . . . . . . . . . . . .
Type 2 Fault Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description: Type 2 Fault Logic . . . . . . . . . . .
Type 2 Fault Status Indication Circuits . . . . . . . .
“RF Drive Estimate” Circuit. . . . . . . . . . . . . . . . . . . . . . .
Type 3 Faults. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VSWR Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DX-10 Transmitter Action When VSWRs are Detected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Single VSWR Action . . . . . . . . . . . . . . . . . . . . . .
Multiple VSWR Action. . . . . . . . . . . . . . . . . . . . .
VSWR Logic: Circuit Descriptions.. . . . . . . . . . . . . . .
“NOR” gate U43C. . . . . . . . . . . . . . . . . . . . . . . . .
“Pulse Stretch” (one-shots U48B and U48A) . . .
Generating Type 3 Faults (VSWR Logic Circuit Description Continued) . . . . . . . . . . . . . . . . . . . . . . . . . .
Detecting Multiple VSWR “Hits” . . . . . . . . . . . .
“Status Indicate Latch” Circuits (U47BU49A and U47A-U49B) . . . . . . . . . . . . . . . . . . .
“VSWR Induced Lower” Circuits . . . . . . . . . . . .
Type 3 Fault Gate, U47C . . . . . . . . . . . . . . . . . . .
VSWR Status Indication Circuits . . . . . . . . . . . . . . . . .
VSWR Self-Test Circuit . . . . . . . . . . . . . . . . . . . . . . . . . .
VSWR Self-Test, Circuit Description . . . . . . . . . . . . .
Overall Circuit Function . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual VSWR Self-Test Inputs. . . . . . . . . . . . . . . . . .
“Turn-On Induced” VSWR Self-Test Input Circuit
and One-Shot U68A . . . . . . . . . . . . . . . . . . . . . . . . . .
Self-Test Pulse to output Monitor A27 . . . . . . . . . . . .
“VSWR Self-Test” Latch U64A . . . . . . . . . . . . . . . . .
Self-Test Status Indication Circuits . . . . . . . . . . . . . . .
Self-Test “Passes”: VSWR Logic is Functioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VSWR Self-Test Fails (VSWR Logic has
Failed): . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Type 4 Faults: Circuit Descriptions . . . . . . . . . . . . . . . . .
“Supply Faults” Sensing Circuit Descriptions . . . . . . . . .
“Supply Fault” Circuits (Type 4, and Some Type 1
Faults). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
“Supply Fault” Comparators on the LED
Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regulator Fault Alert Outputs. . . . . . . . . . . . . . . .
Positive Regulated Supply Faults . . . . . . . . . . . . .
Analog Input, +15V Input. . . . . . . . . . . . . . . . . . .
xvi
Q-16
Q-16
Q-16
Q-16
Q-17
Q-17
Q-17
Q-17
Q-19
Q-19
Q-19
Q-19
Q-19
Q-20
Q-20
Q-20
Q-20
Q-20
Q-20
Q-20
Q-20
Q-22
Q-22
Q-22
Q-22
Q-24
Q-24
Q-24
Q-24
Q-24
Q-25
Q-25
Q-25
Q-25
Q-25
Q-25
Q-25
Q-25
Q-26
Q-26
DC Regulator +5V Fault Input (Type 1 Fault) . . .
Negative regulated Supply Faults . . . . . . . . . . . . .
DC Regulator Modulated B- Supply Fault
(Type 1 Fault) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Type 4 Faults, Status Indicator Circuits . . . . . . . .
Type 5 Fault: Conversion Error . . . . . . . . . . . . . . . . . . . .
External Indicate: . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Indicate: . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Type 6 Fault: Envelope Error . . . . . . . . . . . . . . . . . . . . . .
Envelope Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Envelope Detector Circuit Inputs . . . . . . . . . . . . . . . . .
Envelope Detector Circuit Outputs . . . . . . . . . . . . . . . .
Circuit Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Inputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog Divider. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Linearity Compensation Circuit, Q2 . . . . . . . . . . .
Audio Peak Detectors . . . . . . . . . . . . . . . . . . . . . .
Comparator U73 . . . . . . . . . . . . . . . . . . . . . . . . . .
Envelope Error Status Outputs . . . . . . . . . . . . . . .
Envelope Error Detection Sensitivity . . . . . . . . . .
“RF Sense” Circuits on the LED Board . . . . . . . . . . . . . .
“Oscillator Fault” Sensing . . . . . . . . . . . . . . . . . . .
Buffer and Predriver Fault Sensing . . . . . . . . . . . .
Status Indicator Circuits. . . . . . . . . . . . . . . . . . . . .
Oscillator Fault. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Buffer Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Predriver Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Printed Circuit Board Maintenance. . . . . . . . . . . . . . . .
Replacing MOSFET Devices . . . . . . . . . . . . . . . . . . . .
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Q-26
Q-26
Q-26
Q-26
Q-26
Q-26
Q-26
Q-27
Q-27
Q-27
Q-27
Q-27
Q-27
Q-27
Q-27
Q-27
Q-27
Q-28
Q-28
Q-28
Q-28
Q-29
Q-29
Q-29
Q-29
Q-29
Q-29
Q-29
Q-29
Q-29
Section R
Switch Board/Meter Panel (A31)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multimeter Circuit (M1) . . . . . . . . . . . . . . . . . . . . . . . . .
Meter Selection Circuit . . . . . . . . . . . . . . . . . . . . . .
Metering Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Current Meter Circuit (M2) . . . . . . . . . . . . . . . .
Power Meter Circuit (M3). . . . . . . . . . . . . . . . . . . . . . . .
Negative 15 Volt Power Source . . . . . . . . . . . . . . .
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Symptom: Incorrect Meter Indications . . . . . . . . . . . . . .
Possible Causes: . . . . . . . . . . . . . . . . . . . . . . . . . . . .
R-1
R-1
R-1
R-1
R-1
R-1
R-1
R-2
R-2
R-2
R-2
R-2
R-2
Section S
Test Equipment
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S-1
Basic Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . S-1
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section I
Introduction/Specifications
1.1 Scope and Purpose
This technical manual contains the information necessary to
install and maintain the DX-10 AM TRANSMITTER. The various sections of this technical manual provide the following types
of information.
a. Section I, Information/Specifications, provides introduction to technical manual contents.
b. Section II, Installations, provides detailed installation procedures and initial turn on instructions.
c. Section III, Operation, provides identification and functions of panel and board mounted controls and indicators
as well as of components located on the interior of the
transmitter.
d. Section IV, Theory of Operation, provides detailed theory
of operation of the various sections of the transmitter not
covered in later sections as well as diagrams that apply to
the overall transmitter.
e. Section V, Maintenance, provides preventive and corrective maintenance information as well as tuning procedures
(alignment procedures).
f. Section VI, Troubleshooting, provides a listing of the
protection devices in the transmitter as well as low power
and high power troubleshooting procedures.
g. Section VIA, Emergency Operating Procedures, provides
emergency modes of operation.
h. Section VII, Parts List, provides a parts list for the overall
transmitter.
i. The following sections provide principles of operation,
maintenance information, parts lists, and diagrams for
boards in the DX-10 Transmitter:
Section A, Oscillator (A17)
Section B, Buffer Amplifier (A16)
03/16/2009
Section C, RF Amplifier Modules (A40-A91)
Section D, Driver Combiner/Motherboard (A14)
Section E, Driver Supply Regulator (A22)
Section F, RF Multimeter (A23)
Section G, RF Combiners: Binary Combiner/Motherboard
(A18)
and Main Combiner/Motherboard (A19, A20)
Section H, Output Sample Board (A26) and Output Monitor (A27)
Section J, Analog Input Board (A35)
Section K, Analog to Digital Converter (A34)
Section L, Modulation Encoder (A36)
Section M, DC Regulator (A30)
Section N, External Interface (A28)
Section P, Controller (A38)
Section Q, LED Board (A32)
Section R, Switch Board/Meter Panel (A31)
j. Section S, Test Equipment, provides a list of the test
equipment recommended to perform maintenance on the
transmitter.
k. Section T, Supplements
1.2 Specifications
The brochure at the end of the manual gives the specifications
for the DX-10 Transmitter.
NOTE
Harris maintains a policy of continuous improvements on its
equipment and therefore reserves the right to change specifications without notice.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
1-1
1-2
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section II
Installation
2.1 Introduction
This section of the technical manual provides detailed installation procedures and initial turn on instructions for the DX-10 AM
TRANSMITTER. Information in this section includes the following:
a. Installation drawings - refer to Transmitter Outline Drawing 839-6208-264 for dimensions, location of entry openings for wiring, and air system information.
b. General installation information provides information
which will be useful or necessary in installation planning.
This information should be read before starting actual
installation.
c. Setup includes work that should be accomplished before
moving the transmitter in place.
d. Pre-Installation Inspection should be accomplished after
receiving the transmitter and before beginning mechanical
installation.
e. Mechanical Installation includes detailed information on
setting the transmitter in place.
f. Electrical Installation describe connection of AC power,
Customer Interface Connections, external interlock connections, audio input connections and RF output connection.
g. Remote Control Connection includes information on remote control interfacing and connections.
h. Pre Turn-On Mechanical and Electrical Checks should be
accomplished after completing installation and before initial turn-on.
i. Initial Turn On Procedures provide step-by-step procedures for applying power and turning the transmitter on to
insure that various sections of the transmitter are working
properly.
j. Figures are located at the end of this section, and are
referred to throughout the installation and turn-on procedures.
k. The DX-10 transmitter is shipped nearly completely assembled and ready for installation. However, one or more
vacuum capacitors in the output network are removed and
packed separately for transport. You will install the vacuum capacitor or capacitors during “Electrical Installation.”
2.2 Unpacking
Carefully unpack the transmitter and perform a visual inspection
to determine that no apparent damage was incurred during
shipment. Retain the shipping materials until it has been determined that the unit is not damaged. The contents of the shipment
should be as indicated on the Packing Check List which accompanies each shipment. If the contents are incomplete or if the unit
03/16/2009
is damaged electrically or mechanically, notify the CARRIER
and HARRIS CORPORATION.
2.2.1 Returns and Exchanges
Damaged or undamaged equipment should not be returned unless written approval and a Return Authorization is received
from HARRIS CORPORATION, Broadcast Division. Special
shipping instructions and coding will be provided to assure
proper handling. Complete details regarding circumstances and
reasons for return are to be included in the request for return.
Custom equipment or special order equipment is not returnable.
In those instances where return or exchange of equipment is at
the request of the customer, or convenience of the customer, a
restocking fee will be charged. All returns will be sent freight
prepaid and properly insured by the customer. When communicating with HARRIS CORPORATION, Broadcast Division,
specify the HARRIS Order Number or Invoice Number.
2.2.2 Factory Test Data
During electrical installation and initial turn-on procedures, reference will be made to “Factory Test Data,” which includes
meter readings, measured performance data, and other data taken
during factory tune-up and testing of your transmitter. This data
is normally packed in an envelope and may be inserted in the
technical manual, or may be packed with the transmitter. Locate
the Factory Test Data and set it aside where it will be readily
available for reference during installation and turn-on.
2.3 General Installation Information
The following installation instructions are of a general nature
only but should be read before any actual installation effort is
started. Also, refer to drawing 839-6208-264, “Cabinet Outline,
DX-10,” sheets 1 and 2).
2.3.1 Transmitter Space Requirements
The DX-10 Transmitter has been designed for rapid and diverse
installation. In addition to the 72 inch width by 33 inch depth of
the equipment, a minimum of 26 inches should be allowed for
maintenance access from both the front and rear of the cabinet.
2.3.2 Access for External Connections
Signal and power wires can be brought into the transmitter through
several different entries. There are two inch diameter round holes
in both the floor and the top of the power supply compartment, for
access for AC power wiring and ground strap connections. Two
inch diameter round holes are also provided at the front of the center
compartment (top and bottom), for audio, remote control and
monitoring wiring. Location of entry openings is shown in Cabinet
Outline drawing, 839-6208-264 sheet 1.
All cables and wiring passing through the openings in the floor
of the transmitter, pass into the base of the transmitter. Rectangular cutouts are provided at the sides of the transmitter base for
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-1
cable entry if cable trenches or conduits in the floor are not
provided.
The RF output connector is located on the top of the transmitter,
near the left rear corner (see Figure 2-4, a top view of the
transmitter). Location of the terminal board for the AC Power
input connection (TB5) is shown in Figure 2-3, DX-10 Rear
View. Remote Control terminal boards TB1 and TB2 are shown
in Figure 2-6. Audio Input terminal board A28TB3 (located on
the External Interface board, A28) is also shown in Figure 2-6.
The DX-10 Transmitter is divided into three sections or compartments. As viewed from the front of the transmitter.
The left compartment contains the output network components
and a blower for forced convection cooling. The output network
compartment is accessed by removing a panel at the back.
The center section is divided into a non-interlocked compartment in the front and a Power Amplifier compartment in the
back. The front non-interlocked compartment contains printed
circuit boards and the customer interface terminals, accessed
through a hinged front door with a magnetic catch. The plug-in
RF amplifier modules are accessible through the interlocked
door at the rear of the front compartment. The power amplifier
combiner/motherboards and PA combiner are accessible
through a panel at the back of the transmitter. (This rear access
panel does not have interlock switches, but removing it will
cause the air pressure switch to open and shut the transmitter off).
The third compartment, at the right of the transmitter, contains
power supplies, AC power contactors, ground strap connection
points, and AC power input terminals. Access is through an
interlocked door at the front and through a panel at the back of
the transmitter.
2.3.3 AC Power
Ratings for fuses or circuit breakers for various input voltage
ranges are given in Table 2-1. Input power wires from the wall
disconnect box should run only to the transmitter AC Power
input terminal board, TB5. Specific connections to be made to
TB5 are given in Electrical Installation paragraphs.
2.3.4 Transmitter Cooling
Cooling air for the transmitter enters at two locations and leaves
the transmitter through a grill at the top. Air inlets and outlets are
shown on the Cabinet Outline drawing 839-6208-264, sheet 1).
Air inlets and outlets should not be obstructed in any way.
Maximum inlet temperature at the back of the transmitter should
not be more than 50 degrees C (122 degrees F).
The power supply compartment is cooled by natural convection cooling, with air entering through the lower portion of
the back door and leaving through the grill at the top of the
compartment. Warm air rises by chimney action in the compartment, and provides cooling air flow. In addition, a small
amount of forced exhaust air from the PA’s is routed through
this compartment and exhausted through the top of the transmitter.
Table 2-1
Required AC Power Line Service Capacity
Nom. Line Voltage
Nominal Fuse Size
Minimum Wire Gauge
(Notes 1,2)
(Note 3)
197V
100A
70A
4AWG
208V
100A
70A
4AWG
219V
100A
70A
4AWG
229V
60A
60A
6AWG
240V
60A
60A
6AWG
251V
60A
60A
6AWG
259V
60A
60A
6AWG
270V
60A
50A
6AWG
281V
60A
50A
6AWG
341V
WYE
60A
40A
8AWG
T-1 Configuration
360V
60A
40A
8AWG
Ref. 839-6208-282
379V
60A
40A
8AWG
397V
60A
40A
8AWG
416V
60A
40A
8AWG
435V
60A
40A
8AWG
449V
60A
40A
8AWG
468V
30A
30A
8AWG
Note 1. Blade adapters are commercially available to adapt a fuse to a larger existing disconnect switch.
Note 2. We do not recommend fuses with renewable links.
Note 3. Wire is type THW or equivalent 75 degree C insulation.
2-2
AC Power
Configuration
DELTA
T-1 Configuration
Ref. 839-6208-241
Disconnect Box Size
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Forced convection is used to cool the output network and the
Power Amplifier compartment. A blower at the bottom of the
Output Network compartment draws air through two filters in
the rear compartment panel, and down past the output network
components. The blower outlet forces air up through the power
amplifier compartment and out through the grille at the top of
the compartment. The forced air flow past the PA module heat
sinks removes the heat generated in the PA MOSFETs.
General air system requirements are shown on the Cabinet
Outline 839-6208-264 sheet 2). If exhaust ducting is used, note
air pressure requirements in the exhaust hood and the top of the
transmitter (referenced to room air pressure), the space between
the bottom of the exhaust hood and the top of the transmitter, and
a rain proof weather hood outside the building. Also, realize that
the very high overall efficiency of this transmitter means that
very little exhaust heat is generated, so the exhaust ducting from
the transmitter may not be required.
If exhaust ducting is used, also remember that there is an adjustment (C101) made from the top of the transmitter, over the output
network compartment, and there is also an access panel above
the center compartment. This top access panel allows convenient
access for cleaning and other routine maintenance of driver and
pre-driver tuning coils. Ducting, if used, should be planned to
allow access to the adjustment and top access panel.
2.3.5 Transmitter Grounding & RF Output Connec-
tions
The transmitter must be grounded to the station ground system with
a copper strap at least two inches wide and heavy enough (at least
0.020 inch thickness) to prevent mechanical damage that would
interrupt this ground circuit. The copper ground strap must be
connected to either grounding block E14 at the bottom of the power
supply compartment or the ground terminal (E15) provided at the
side of the power supply compartment. The outer conductor of the
coaxial transmission line alone does not provide a proper ground
for the transmitter. Figure 2-3 shows locations of ground connection
points E14 and E15.
The RF Output connector in the DX-10 is a 1-5/8 inch EIA flanged
connector. A female connector is provided on the transmitter, and
a bullet is provided to allow mating with either a male or a female
connector on the RF coaxial cable. The bullet and an O-ring for the
EIA Connector are packed separately; refer to the Packing Check
List. Figure 2-4, a top view of the transmitter, shows this connector.
After the rf output termination is made, make sure the spark gap,
E101 in the Output Network Compartment, is set to 0.050 inches.
The key to a rapid and successful setup is careful planning prior
to installation of the system. HARRIS offers, as an option,
engineering services to review and comment on proposed installations. In addition, HARRIS offers, as an option, design, fabrication, and installation services to any required level for total
integration of the system into a facility.
Several specific items should be planned for prior to installation
of the system. These items are:
a. Installation of AC power, including a wall mounted Disconnect Box, with fuses or circuit breakers rated per Table 2-1.
b. Installation of utility outlets within 8 to 10 feet from the
front and rear of the planned transmitter location, for test
equipment. Outlet boxes may also be installed on the top
of transmitter cabinet.
c. Installation of ground strap runs to the required locations
and provision to ensure that the straps are electrically
bonded to station ground.
d. Installation of any planned air ducts and cable troughs.
e. Purging and filtering of the supply air duct system, if used,
to assure cleanliness of cooling air.
Table 2-2
Special Installation Tools and Equipment
Lifting Equipment (Fork Lift, etc.)
1535 lbs (698 kg) capacity (to lift transmitter’s weight).
Hand Tools (pry-bar, screwdrivers, wrenches, etc.)
For opening wooden crates etc.., and installing hardware.
Shims (2" by 2")
Aluminum, assorted thicknesses, for leveling transmitter.
Hand Operated Hole Punch
For adding 0.25" hardware holes to 0.020" thick copper
ground strap at transmitter ground connection.
Ring Lug Crimping Tool
For crimping lugs.
BNC Connector Tooling
Table 2-3
Equipment Supplied With Transmitter and Listed on
Packing Check List Supplied With Transmitter
Bullet for EIA Connector (RF Output Connector)
2.4 Setup Procedures
2.4.1 General Requirements
Prior to installation, pertinent requirements related to the installation and operation of the equipment should have been considered and provided for. The design considerations should
encompass physical dimensions of the equipment, access for
03/16/2009
maintenance, relationship to other equipment, allowance for
routing and distribution of input and output lines, adequate
lighting, power access, ducting for cooling, if required, and
protective grounding.
O-Ring for EIA Connector
Spare RF Amplifier Module - 992-6967-001
Factory Test Data
Maintenance Manual - 888-2241-002
C101, Vacuum Variable
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-3
f. Installation of RF load, if desired, and testing to assure that
water/air flow is adequate. (Information on sizing an RF
load or dummy load is included in the paragraphs on RF
OUTPUT TERMINAL INSTALLATION in the “ELECTRICAL INSTALLATION” section.)
g. Installation of the major portion of the external air exhaust
system, if used.
h. Assurance that all required hand tools and special installation tools are available.
In summary, it is recommended that all interfaces be installed up
to the “last piece” between the facility and the transmitter, before
the transmitter is set in place. These last interface runs should be
cut to size or customized after the transmitter is set into its final
position.
2.4.2 Equipment Placement
The transmitter should be located to permit adequate maintenance access and sufficient ventilation. Primary AC power cables can enter the transmitter at a variety of locations and the
specific location of entry will need to be determined on site. The
grounding strap between the transmitter and the station earth
ground must be properly connected before AC power wiring is
attached to transmitter.
2.4.3 Pre-Installation Inspection
If you have not already done so, visually inspect the transmitter
to determine that no apparent damage was incurred during
shipment. This should include opening doors, and removing rear
panels, to check for cracked or broken printed circuit boards, and
cracked or broken insulators and support brackets or assemblies,
including the insulating support brackets for large output network coils. If any damage appears to have been caused during
shipment, notify both the shipper and Harris (refer to the paragraph “Unpacking”).
Close and secure doors and replace all rear panels before moving
the transmitter.
2.5 Mechanical Installation
2.5.1 Equipment Positioning
Following removal of the shipping crate, move the cabinet on its
skid as near as possible to its permanent position. If shipping
bolts have been used, they will be located at each corner of the
skid. Remove the bolts from the underside of the skid.
NOTE
Positioning of the cabinet is to be performed by experienced personnel to prevent damage to the equipment or injury to personnel.
With a suitable lifting device, raise one end of the transmitter
cabinet sufficiently to permit the placing of three lengths of
circular bar stock under the cabinet. In this manner the cabinet
can be efficiently and carefully rolled off the skid and into the
desired position in the facility.
2-4
2.5.2 Transmitter Leveling
With the transmitter in its final position, the cabinet must be
checked for uniform foundation support so that the frame is not
twisted out of squareness. Remove all three back compartment
panels (they may be holding the box square). Now, reinstall them
(if possible; if not, determine where the transmitter base must be
shimmed to square the cabinet). When the panels have been
replaced, visually examine the gaps between the top, bottom, and
sides of each panel and the frame (or the next panel) to see if the
gaps are uniform. If the gaps have significant taper or if it is
difficult or impossible to line up any of the 1/4 turn fasteners, the
cabinet is not on a flat floor. Shim the necessary corners of the
transmitter cabinet, using metal shims, to bring the cabinet back
into square and to make the gaps between panels or doors and
their frames uniform.
2.5.3 Ground Strap Installation
Remove the grounding block (E14) located on the floor of the
transmitter’s power supply cubicle, at the rear corner near the
door. Punch holes in a copper grounding strap to match the holes
in the grounding block. Place the strap under the grounding block
and bolt the grounding block back in place. A 2-inch wide strap
may be run out the 2-inch diameter access hole in the floor of the
compartment or through the notch in the bottom of the rear
compartment door. The strap should also be brazed to the station
earth ground.
An alternative grounding point is provided if the grounding strap
is brought in from the top of the transmitter. This is a grounding
stud, E15, located on the outside wall of the power supply
compartment, about one third of the way up at the back. Refer
to Figure 2-3 for location of the ground connection points.
NOTE
It is important that a ground strap be installed from the transmitter cabinet to station ground, to provide a low impedance path
for RF and transient currents. The outer conductor of the RF
transmission line is not an adequate ground. Improper grounding
will result in component failures under lightning or transient current conditions.
Any adjustments to exhaust ducting, if used, can be made at this
time. The top of the transmitter should be covered while working
above it, to prevent dropping hardware or metal fragments into
the transmitter through the air exhaust openings.
2.6 Electrical Installation
NOTE
DX-10 transmitters are usually shipped with T1 and T2 connected for 240 VAC Delta operation, unless the customer has
specified another voltage or has specified a WYE configuration.
THE END USER MUST CHECK INCOMING LINE VOLTAGE
AND SELECT THE TAPS APPROPRIATE FOR LOCAL AC INPUT CONDITIONS PRIOR TO TURN-ON. Failure to do so
could result in major equipment damage.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
2.6.1 Power Requirements
The DX-10 is designed to be operated from a 3 phase, 197 to 281
Vac, 3 wire closed delta connected 48 to 63 Hz power source,
OR a 3 phase, 341 to 468 Vac, 4 wire wye connected 48 to 63
Hz power source.
The nominal line to line voltage at the facility must be reasonably
accurately known. If necessary, measure the incoming AC voltage with a digital voltmeter, then subtract 1% for typical line sag.
Measure from line to line, NOT from line to ground (the supplement on three-phase AC power in Section T includes information
on voltages in three-phase AC power systems if you are not
already familiar with three-phase power).
The AC power to the transmitter must be supplied from a
properly sized disconnect switch box, with properly sized fuses.
This can be determined from table 2-1, “Required AC Power
Line Service Capacity,” using the known nominal line voltage
determined in the previous paragraph.
2.6.2 Delta and Wye Connections
Some of the AC power connections within the transmitter depend on whether the AC power source is delta or wye connected.
In the United States, and most other locations, 220 to 240 volt
three wire DELTA connected three phase power will normally
be provided. In some locations, however, 380 to 440 volt 4-wire
WYE connected power may be used. Refer to the following
paragraphs on “3 WIRE DELTA AC POWER WIRING” or on
“4 WIRE WYE AC POWER WIRING,” as required. (Again, the
supplement on three-phase AC power in Section T includes basic
information on delta and wye connected AC power.)
Also, blower motor junction box strapping depends on whether
50 or 60 Hz power is supplied. Both 50 and 60 Hz strapping
information is provided for both DELTA and WYE connections.
2.6.3 High Voltage Transformer, Primary winding
Terminals
High Voltage supply transformer T1 has three primary windings,
and each winding has voltage terminals at the top of the transformer. There are three “groups” of voltage terminals; each
group has the following taps: 0, +11, -11, and 208, 240, and 270.
These are voltage taps; for example, for a 240 volt input, “240"
and ”0" taps are used; for 230 volt inputs, “240" and ”-11" are
used; and for 220 volt inputs, “208" and ”+11" taps are used.
There are three heavy AC power input wires (numbers 4, 5 and
6), one to each primary winding; three heavy jumpers between
windings; and three smaller wires (numbers 106, 12 and 13)
which go to the blower motor fuses.
2.6.4 3 Wire Delta AC Power Wiring
If you have 4-wire Wye AC power at your location, skip the
following paragraphs, and refer to “4 WIRE WYE AC POWER
WIRING.”
AC power distribution in the DX-10 is shown on DX-10 Overall
Schematic Diagram, Delta Connection (drawing 839-6208-241,
sheets 1 and 2).
03/16/2009
WARNING
ENSURE THAT ALL AC POWER IS OFF PRIOR TO STARTING THE FOLLOWING INSTALLATION PROCEDURE.
2.6.5 AC Power Wiring, three wire Delta Configura-
tion
Use the following procedure to verify AC power wiring in the
transmitter, or, if necessary, to change transformer tapping,
blower motor connections, and wire number 31.
2.6.5.1 Transformer connections, 3-WIRE DELTA CONNECTION
a. Refer to Table 2-4, “Line Voltage Taps for Delta Service,”
and find the line voltage in the first column that comes
closest to the nominal line voltage for your facility (the
“nominal voltage” is line-to-line voltage, and is NOT
referenced to ground). Read across Table 2-4 to verify (and
change, if necessary), all the following connections:
b. Connect wires 4, 5 and 6 to T1 terminals indicated in the
table. One wire goes to each transformer winding.
c. Connect jumpers numbers 208, 209 and 210 between the
T1 terminals indicated. One jumper goes from winding A
to winding B; a second goes from from B to C, and a third
goes from C to A. Each jumper connects a 208, 240, or 270
volt tap on one winding to a -11, 0, or +11 tap on another
winding.
d. Connect wires 12, 13, and 106 to T1, as indicated for both
the nominal LINE VOLTAGE and LINE FREQUENCY
IN USE (refer to the last two columns of Table 2-4). One
of these wires goes to each primary winding on T1. (These
three wires go to blower motor fuses F7, F8 and F9).
e. Locate low voltage supply transformer T2, on the shelf on
the outside wall of the power supply compartment, and
check Table 2-4 to verify connections for wire 36 and wire
37. If necessary, remove the plastic safety shield and
connect wires 36 and 37 to the T2 terminals indicated in
the table.
2.6.6 Blower Motor Junction Box Strapping
a. Remove the junction box cover from the side of the blower
motor. Verify (and change if incorrect) that the correct
wire numbers are tied together, using the wire nuts, as
indicated in the second part of table 2-4. Replace the
junction box cover.
b. Other “Three Phase Delta” Connections:
c. Remove the protective cage which covers the AC input
terminal board TB5 and high voltage supply contactors K1
and K2. These components are located on the outside wall
of the power supply compartment. (see Figure 2-3).
d. Verify that wire number 31 connects to the bottom of fuse
F1.
2.6.7 AC Input Power Connection
a. Connect the AC line from the wall disconnect switch box
to TB5-1, 2, and 3. (Terminal 4 is NOT used in Delta
configurations).
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-5
Table 2-4
Line Voltage Taps for Delta Service
Nominal Line
Voltage
Wire Numbers, to T1 Taps:
Wire Numbers, to T2 Taps
AC to Blower Motor
AC Input 4,5,6
Jumpers
36 to T2 Tap:
37 to T2 Tap:
60Hz 12,13,106 50Hz 12,13,106
to T1 Taps:
208,209,210
to T1 Taps:
to T1 Taps
Jumper between
T1 Taps
197
208
208 to -11
208
-11
+11
-11
208
208 to 0
0
219
208 to +11
+11
229
240
240 to -11
240
-11
-11
208
240
240 to 0
0
251
240 to +11
+11
0
259
270
270 to -11
270
-11
240
270
270 to 0
0
281
270 to +11
+11
Blower Motor Junction Box Strapping, for “Low Voltage”
Nominal voltage required by motor:
At 50 Hz: 193 Vac +/-10%
At 60 Hz: 230 Vac +/-10%
Junction Box Strapping (Use Wire Nuts for connecConnect:
AC Power Wire #46 to “3" and ”9"
tions):
AC Power Wire #47 to “2" and ”8"
AC Power Wire #48 to “1" and ”7"
Connect together:
“4", ”5", and “6"
Figure 2-1
Blower Motor Junction Box Strapping for “Low Voltage”
2-6
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
b. This completes AC power wiring. Skip the paragraphs on
“Wye” connections and go to the paragraph “Power Wiring Check.”
2.6.8 4 Wire WYE AC Power Wiring
The following paragraphs apply only if you have a 4-wire Wye
AC power configuration. If you have 3-wire Delta power, skip
these paragraphs and go directly to “Power Wiring Check”
paragraph.
WARNING
ENSURE THAT ALL AC POWER IS OFF PRIOR TO STARTING THE FOLLOWING INSTALLATION PROCEDURE.
2.6.8.1 AC Power Wiring, Four Wire WYE Configuration
Use the following procedure to verify AC power wiring in the
transmitter, or, if necessary, to change transformer tapping,
blower motor connections, and wire 31.
2.6.8.2 Transformer Connections, 3-WIRE WYE Connection
a. Remove the protective cage over AC input terminal block
TB5 and high voltage supply primary contactors K1 and
K2. This cage or cover is located on the outside wall of the
power supply compartment. (Refer to Figure 2-3).
b. Refer to Table 2-5, “Line Voltage Taps for Wye Service,”
and find the line voltage in the first column that comes
closest to the nominal line voltage for your facility (the
“nominal voltage” is line-to-line voltage, and is NOT
referenced to ground). Read across Table 2-5 to verify (and
change, if necessary), all the following connections:
c. Connect wires 4, 5 and 6 to T1 terminals indicated in the
table. One wire goes to each transformer winding.
d. Connect jumpers numbers 208, 209 and 210 between the
T1 terminals indicated. One jumper goes from winding A
to winding B; a second goes from from B to C, and a third
goes from C to A. Each jumper connects a -11, 0 or +11
tap on one winding to a -11, 0, or +11 tap on another
winding. When completed, all three “-11" taps, or all three
”0" taps, or all three “+11" taps will be connected together.
(Use ALL THREE jumpers).
e. Connect wires 12, 13, and 106 to T1, as indicated for both
the nominal LINE VOLTAGE and LINE FREQUENCY
IN USE (refer to the last two columns of Table 2-5). One
of these wires goes to each primary winding on T1. (These
three wires go to blower motor fuses F7, F8, and F9).
f. Locate low voltage supply transformer T2, on the shelf on
the outside wall of the power supply compartment, and
check Table 2-5 to verify connections for wire 36 and wire
37. If necessary, remove the plastic safety shield and
connect wires 36 and 37 to the T2 terminals indicated in
the table.
2.6.9 Blower Motor Junction Box Strapping
a. Remove the junction box cover from the side of the blower
motor. Verify (and change if incorrect) that the correct
wire numbers are tied together, using the wire nuts, as
03/16/2009
indicated in the second part of table 2-5. Replace the
junction box cover.
2.6.10 Other “FOUR WIRE WYE” Connections
a. Verify that wire number 31 connects to TB5-5 (this connection returns one side of the low voltage supply transformer primary to NEUTRAL. There is a permanent
jumper from TB5-4 (NEUTRAL) to TB5-5, and TB5-5
accommodates the ring lug on wire number 31).
2.6.11 AC Input Power Connection
a. Connect the AC line from the wall disconnect switch box
to TB5-1, 2, and 3. The fourth NEUTRAL wire from the
wall disconnect box connects to TB5-4. Not that the NEUTRAL is NOT connected to the transmitter ground, but is
carried back by the fourth wire to the “Neutral” of the
power source.
b. This completes AC power wiring. Go to the next paragraph, “Power Wiring Check.”
2.6.12 Power Wiring Check
Double check all power wiring, as follows:
a. Double check that the correct terminals were used per
Table 2-4 (Delta connections) or 2-5 (Wye connections).
CAUTION
Ensure that the SAME taps are used on each of the three primary
windings on T1. Failure to do this will result in increased hum
level in the transmitter output, possible excessive heating of
transformer T1, and possible shut down of the transmitter with a
SUPPLY FAULT overload.
b. Double check that the same voltage taps were used on T2
as on T1.
c. Reinstall the protective plastic shield over T2 connections,
if the shield was removed.
d. Confirm that all connections on T2, T1, and TB5 are
tightened firmly.
e. Reinstall the metal cage over TB5 and the contactors.
f.
2.6.13 Meter Shunt Removal
The four meters used in the transmitter have taut band movements and are protected during transport by wire shunts across
their terminals. Remove these protective shunts as follows:
a. Open the front center door of the transmitter. Each of the
three meters on the switch board/meter panel has a shunt
across its terminals (these are the multimeter VOLTMETER, CURRENT meter, and POWER meter. Loosen each
meter’s terminal nuts and remove and discard the shunt
wire with its red tag.
b. Retighten all 6 meter terminal nuts, and close the transmitter’s front door.
c. Open the front power supply compartment door, to gain
access to the back of the RF multimeter. To open the door,
use a screwdriver to loosen the door’s quarter-turn fasteners.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-7
Table 2-5
Line Voltage Taps for Wye Service
Nominal Line
Voltage
Wire Numbers, to T1 Taps:
Wire Numbers, to T2 Taps
AC to Blower Motor
AC Input 4,5,6
Jumpers
36 to T2 Tap:
37 to T2 Tap:
60Hz 12,13,106 50Hz 12,13,106
to T1 Taps:
208,209,210
to T1 Taps:
to T1 Taps
Jumper between
T1 Taps
341
208
-11 to -11
208
-11
270
240
360
0 to 0
0
379
+11 to +11
+11
240
208
397
240
-11 to -11
240
-11
270
240
416
0 to 0
0
435
+11 to +11
+11
240
208
449
270
-11 to -11
270
-11
270
240
468
0 to 0
0
Blower Motor Junction Box Strapping, for “Low Voltage”
Nominal voltage required by motor:
At 50 Hz: 383 Vac +/-10%
At 60 Hz: 460 Vac +/-10%
Junction Box Strapping (Use Wire Nuts for connecConnect:
AC Power Wire #46 to “3"
tions):
AC Power Wire #47 to “2"
AC Power Wire #48 to “1"
Connect together:
“6" and ”9"
“5" and ”8"
“4" and ”7"
Figure 2-2
Blower Motor Junction Box Strapping for “High Voltage”
2-8
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
d. Loosen the Multimeter’s terminal nuts and remove the
wire shunt and red tag. Retighten the terminal nuts, and
close and secure the power supply compartment door
again.
2.6.14 Controller Battery Backup
The transmitter’s controller remembers the LOW, MED, and
HIGH power settings. If the AC main power is disconnected, a
1 farad energy storage capacitor will provide backup power to
these memory circuits for at least two hours.
If longer backup time is desired, 3 AA alkaline batteries can be
installed to give indefinite backup time. All backed-up circuits
are low-power CMOS, so that total current drain is less than 1
milliampere.
The batteries should not be installed until the transmitter is
powered up. Batteries will be installed during Initial Turn-On
Procedures.
2.7 Customer Interface Connections
The following paragraphs include information on customer interface connections for audio input, RF output, external interlocks, PA turn-off, and frequency and modulation monitors (if
used). Remote control interface will be described separately.
2.7.1 Audio Input Connections
Audio Input connections include making connections to the
transmitter’s audio input, then selecting one of three audio input
connectors on Analog Input board A35 to match the audio
program source’s internal impedance if optimum overshoot and
frequency response is desired.
Use a shielded pair audio cable for connection between audio
source equipment and the DX-10 transmitter’s audio input terminals, A28TB3 on the External Interface Board, A28. Refer to
Figure 2-6, for location of the audio input, in the front non-interlocked compartment.
Audio input connections are as follows:
TB3-1: Shield (to transmitter chassis ground).
TB3-2: Audio (+)
TB3-3: Audio (-)
TB3-4: Optional shield connection, capacitively coupled to
transmitter chassis ground).
The audio input cable SHIELD should be grounded at only one
end, either at the processor or at the ground terminal (TB3-1) on
the transmitter’s audio input terminal strip. Connecting the
shield at both ends can result in ground loop problems and
increased system noise.
In the DX-10, TB3 terminal 4 provides an AC coupled path to
the transmitter cabinet at this point. In some installations, lower
noise may be obtained by connecting the audio cable shield to
this terminal.
03/16/2009
Audio input terminal board A28TB3 is shown on sheet 1 of the
External Interface Board Schematic Diagram, on sheet 1 of the
External Interface schematic diagram 839-6208-099. The following paragraphs include additional information which may be
useful in planning and connecting the audio input.
2.7.2 Audio Phasing
If you use asymmetrical audio processing equipment for more
than 100% positive modulation, proper phasing of the transmitter’s audio input will be required. At audio input terminals TB3-2
and TB3-3, the “+” and “-” symbols refer to audio phasing. If
the audio processor has audio output terminals marked “+” and
“-,” connect one wire of the audio pair (typically red) between
the processor’s “+” output and the transmitter’s “+” input terminal, and connect the other wire (typically black) between the
“-” terminals. This should give proper phasing. (Asymmetrical
audio processing has an output with positive peaks greater than
negative peaks so that positive peak modulation can be greater
than 100%. If asymmetrical audio processing is used, incorrect
phasing will result in low positive peak modulation when audio
level is adjusted for proper negative peak modulation.
2.7.3 Audio Source Impedance
The DX-10 Transmitter uses a Bessel filter at the audio input, to
obtain superior overshoot performance. Performance of this
filter depends on the source impedance of the audio equipment
providing the program signal to the transmitter. The program
source equipment’s specified load impedance is not necessarily
its “source impedance”; for example, some modern equipment
may be specified for a 600 ohm load but have a very low source
impedance, 50 ohms or less.
Audio source impedance selection is NOT critical, unless optimum overshoot performance and frequency response is desired.
2.7.3.1 Selecting Source Impedance
At the top of Analog Input Board A35 are three connectors, J1,
J2 and J3 (see figure 2-7 for location). A white Molex connector
on audio input cable number 100, from the External Interface
board, plugs into J1, J2, or J3. Impedance for each input is silk
screened on the printed circuit board. For optimum overshoot
performance and best high frequency response, the plug should
be used with the jack labeled with an impedance that is closest
to the source impedance of the program source equipment should
be used.
This connection is NOT critical; using the wrong connector may
result in some overshoot or undershoot on square waves and a
slight change in audio frequency response (typically less than 1
dB at 10 kHz).If the audio equipment source impedance cannot
be determined, try “R*s = 600 ohms” for older transformer
equipment, and “R*s less than 50 ohms” for newer equipment
with direct coupled operational amplifier outputs.
2.7.4 RF Output Terminal Installation
Connect the output transmission line from the antenna system to
the RF OUTPUT 1-5/8" EIA flange connector jack located on
top of the transmitter cabinet. Either a male or a female connector
may be used on the coaxial transmission line. If a female con-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-9
nector is used, the bullet supplied with the transmitter, but
packed separately, will be required.
2.7.5 Dummy Antenna Information
It is very useful to be able to switch the transmitter RF output to
a dummy antenna for testing. This testing frequently includes
modulating with tones. With tone modulation, 100% modulation
of an 11 kW carrier produces an average power of 16.5 kW in
the load. Sustained asymmetrical modulation of a 10 kW carrier,
with -100% and +140% peaks, will produce 19 kW of average
power that must be absorbed and dissipated by the load. When
selecting a dummy load, a power rating sufficient for the type of
testing to be done must be selected.
2.7.6 External Interlock (Fail-safe)
External Interlocks can be connected between terminals 1 and 2
on TB1 (the top customer interface screw-terminal block, located at the top of the right side wall of the non-interlocked
compartment).
Key information on External Interlocks is summarized below;
the following paragraphs also include additional data on external
interlocks.
a. A CLOSED circuit between TB1-1 and TB1-2 allows the
transmitter to turn ON.
b. An OPEN circuit between TB1-1 and TB1-2 turns the
transmitter OFF by interrupting the 24 volt AC circuit for
the high voltage supply contactors. The transmitter cannot
be turned on again as long as there is an OPEN circuit
between the External Interlock terminals.
c. If NO External interlocks are used, a jumper must be
connected between External Interlock terminals TB1-1
and TB1-2.
d. The External Interlock circuit is a 24 volt AC circuit,
which operates a 24 Vac relay with a 2 volt-amp coil.
External interlock contacts and wiring should be rated for
1 ampere AC current.
WARNING
DO NOT GROUND ANY PART OF THE EXTERNAL INTERLOCK CIRCUIT. The 24 volt AC supply comes from the
T1 secondary used for the +30 and +60 volt low voltage supplies;
the secondary winding center tap is used for both the +30 volt
output and one side of the 24 volt AC interlock circuit. (See
Section M, DC Regulator board, for additional information,
including a simplified diagram).
2.7.6.1 Using The External Interlock
The External Interlock should be used for any function which
should positively turn the transmitter OFF by turning off its high
voltage supply when an interlock fault occurs. Examples include
a remote fail-safe connection, and safety interlocks on phasor
cabinets or other enclosures which could expose personnel to the
transmitter’s RF output when opened.
NOTE
The “External Interlock” should not be used for antenna pattern
switching, which requires only brief interruption of RF power
2-10
output. The PA TURN OFF connection, described below, should
be used for that purpose.
More than one “external interlock” can be used by connecting
the normally closed interlock switches in series. All external
interlock switches should be normally closed when the interlocked enclosure or circuit is in the safe condition, and should
open when in the unsafe or fault condition.
A closed circuit must be provided between TB1-1 and TB1-2
before the transmitter’s high voltage will come on. Opening or
interrupting this circuit will cause the transmitter primary power
contactors to open and remove AC power from the high voltage
power supply (230 VDC supply). As already noted, the open
circuit voltage between TB1-1 and TB1-2 is 24 VAC, and one
side of the interlock circuit is also at +30 VDC referenced to
transmitter cabinet ground.
CAUTION
DO NOT GROUND ANY POINT IN THE EXTERNAL INTERLOCK
CIRCUIT. ONE SIDE OF THE INTERLOCK CIRCUIT IS AT +30
VOLTS DC, REFERENCED TO GROUND, AND GROUNDING ANY
PART OF THE EXTERNAL INTERLOCK CIRCUIT WILL SHORT
THIS DC SUPPLY.
2.7.7 PA Turn Off
An External (remote) PA TURN-OFF input turns all PA modules
OFF through modulator section action, causing RF output to go
to zero. The PA is held off as long as the EXTERNAL PA
TURN-OFF input is present. “External PA Turn-Off” does NOT
turn off the high voltage supply. As soon as the PA Turn-Off
signal is removed, the transmitter immediately comes back up to
its operating power.
Don’t confuse “PA Turn Off” with the transmitter “Off” remote
control input. PA Turn Off operates the same as the “PA
ON/OFF” switch on the controller board. The remote “OFF”
input operates in the same way as the front panel “OFF” pushbutton switch.
An External PA Turn-Off input requires applying 15 to 29 volts
between TB1-21 and TB1-23 (observe proper polarity). This
input is the same as all other remote control inputs; refer to
information on Remote Control Connections, later in this section, and to Section N, External Interface, for additional information on PA Turn Off and other remote control command
inputs.
NOTE
PA TURN OFF should NOT be used for FAIL-SAFE purposes, or
for interlocks, or for routine transmitter turn off. It is intended to
remove transmitter RF power output during antenna switching
operations, for example, during an antenna pattern change.
2.7.8 Modulation Monitor Connection
If a modulation monitor is used at the transmitter site, use a 50
ohm coaxial cable from BNC jack A27J5 on Output Monitor
Board A27 to the modulation monitor input. (Output Monitor
Board A27 is located at the top of the left side wall of the front
center non-interlocked compartment. See Figure 2-7.) If the
modulation monitor has a high input impedance rather than an
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
internal 50 ohm termination, a 50 ohm, 3 to 5, watt termination
should be used at the monitor.
The modulation monitor sample output, at A27J5, is adjustable
from 0 to 10 volts rms (rf output, at carrier frequency). This level
is first adjusted at LOW power by moving a tap on inductor
L107, then can be adjusted for MEDIUM and HIGH power
levels with controls R7 and R8 on the transmitter Output Monitor
board. Sample level adjustment will be described in “Setting
Modulation Monitor Sample Levels” in the Initial Turn-On
Procedures, later in this section.
If your modulation monitor could be damaged by a 10 V rms RF
input, don’t connect the coaxial cable to the monitor until the
first steps of the procedure for “Setting Modulation Monitor
Sample Levels,” in the Initial Turn On procedure in this section,
have been completed.
2.7.9 Frequency Monitor Connection
If a frequency monitor is used at the transmitter site, a coaxial
cable should be run from BNC jack A17J5 on the Oscillator
board, A17, to the frequency monitor’s input. The RF sample at
A17-J5 is a 5 V peak unmodulated signal, at the transmitter
carrier frequency. The board’s location is shown on figure 2-7.
2.8 Remote Control Connections
Remote Control connections (including connection to Extended
control panels, if used) will be different for each installation. The
following paragraphs include basic information on remote control interfacing; for detailed information, including some typical
interfaces, refer to Section N, External Interface, in this technical
manual.
A summary of key information on remote control connections
follows:
a. Remote Control interface connections are made at TB1
and TB2, in the non-interlocked compartment. See Figure
2-6 for location.
b. Control interface connections require applying a voltage
the desired control interface terminals, to operate an optoisolator. Refer to following paragraphs and to Section N
for interface information.
c. Analog Monitoring (Remote Meter Reading) outputs are
nominally 3.4 volts, from a high impedance source, for a
normal transmitter meter reading at 10 kW output. Connecting Analog Monitoring outputs to any input other than
a high impedance circuit will reduce this level.
d. Status Monitoring Outputs are open-collector outputs.
e. Interface information is summarized on sheet 3 of the
External Interface board schematic diagram (drawing 8396208-099).
Customer Interface terminal boards, TB1 and TB2, located in
the non-interlocked compartment, at the top of the right side, are
used for control and monitoring of the transmitter from a location
outside the transmitter. In most installations, this will be a remote
03/16/2009
control unit, such as the Harris SENTINEL series remote control
units. In some installations, this may also be an extended control
panel located at a transmitter control console or desk.
The Customer Interface of the DX-10 for remote control, metering, and status monitoring is compatible with nearly all remote
control systems, including microprocessor based systems such
as the Harris Sentinel series. With normal transmitter meter
readings, all remote metering output voltages are approximately
3.4 volts DC. This allows for some increase in readings while
still remaining within the 4 volt input limit of remote control
systems such as the Harris Sentinel.
Remote Control inputs are isolated, by optoisolators on the
transmitter’s External Interface board. This permits maximum
flexibility for control inputs, allowing use of either voltage
sources provided on the DX-10 Customer Interface Board or
external batteries or voltage sources. Control inputs can be by
means of relay contact closure, switch closure, or transistor
turn-on. Control inputs may be completely isolated from ground,
or can switch either a positive or negative voltage to ground.
2.8.1 Functions Which Can Be Controlled Or Moni-
tored
The External Interface Schematic Diagram (drawing 839-6208099, Sheet 3) lists control and monitoring functions for each
terminal of TB1 and TB2. These are also printed inside the front
door of the transmitter.
The functions of most control inputs, and most status or monitor
outputs on TB1 and TB2 are the same as the corresponding
push-button control inputs, status indications, or metering functions on the transmitter front panel, as listed in the OPERATION
section (Section 3) of this manual. Paragraphs on “Explanation
of Selected Remote Control Functions” will provide additional
information on some control and monitoring functions.
If the remote control system does not have enough channels
available for all control and status functions, Table 2-6 lists the
minimum recommended control and monitor functions.
2.8.1.1 Interface Information
On the list of functions on sheet 3 of the schematic diagram, a
letter (A through E) is placed next to each terminal number. This
letter refers to a section of a “Characteristic Key” also included
on the diagram. Each “Characteristic Key” provides schematic
diagrams and information which will be useful when planning
interfaces to a remote control unit or to an extended control
panel.
2.8.1.2 Remote “CONTROL”
Each remote control input uses two terminals on TB1 or TB2.
One terminal is “+” and the other is “-.” Applying a voltage
between the terminals is the same as depressing the corresponding “Control” push-button in the transmitter or as operating the
corresponding switch. Voltage applied to these terminals should
be between 15 and 29 volts; corresponding currents are 40 to 70
milliamperes. For convenience, +15 volt and -15 volt sources (at
175 mA maximum current) are provided at TB1-11 and TB1-12,
respectively. Refer to Section N, External Interface, for additional information.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-11
2.8.1.3 Remote “STATUS” Indications
Status outputs at TB1 and TB2 are open-collector transistor
outputs, to ground. When the corresponding status indicator is
illuminated at the transmitter (or when a status panel LED is
RED), the transistor turns on, providing a current sink from the
status output to ground. These status outputs can switch a 6 or
12 volt dc low-current relay, or can provide a logic LOW output
when a pull-up resistor to +5 to +15 volts is used. Maximum safe
voltage at a status output terminal is +15 volts and maximum
safe current into a status output is 100 mA. Refer to Section N,
External Interface, for more information.
2.8.1.4 Remote Meter Readings (“MONITOR” Outputs)
A number of voltages, currents, power levels, and other analog
parameters can be monitored remotely. When a high impedance
remote control system input is connected to a “Monitor Output”
terminal, the nominal output will be +3.4 volts (or -3.4 volts to
monitor -22 V and -8 V supplies) when the transmitter is operating at 10 kW. If the remote control system input is not high
impedance, the loading on the monitor output will reduce the
output voltage. Refer to Section N, External Interface, for additional information.
input (TB1-33 and TB1-35) is paralleled with the OFF button on
the transmitter.
2.9.3 PA Turn OFF
The PA TURN OFF function is NOT the same as the “OFF”
function. The remote PA TURN OFF causes the transmitter
output to go to zero through the action of the modulator. A
control input voltage applied between TB1-21 and TB1-23
causes output power to go to zero and remain at zero until the
“PA Turn Off” remote control input voltage is removed again.
As soon as the control input voltage is removed, the transmitter
output power will return to the already preset level. The High
Voltage (+230 volt) power supply remains energized during a
PA TURN OFF, and no contactors operate.
NOTE
PA TURN OFF should not be used for FAIL-SAFE purposes or
for routine transmitter turn off. It is intended to remove transmitter power output during antenna switching operations, for example, during an antenna pattern change. The +230 volt High Voltage power supply is not turned off during a PA TURN OFF.
2.9.4 “OFF” Function, “PA Turn OFF,” and Exter-
nal Interlock
These three functions all cause RF output to go to zero, but in
different ways, as follows:
2.9 Explanation of Selected Functions
Most remote control functions and monitor outputs are the same
as the corresponding functions or indications in the transmitter.
Some indications and functions will, however, be explained here
to aid in planning and installing a remote control system.
2.9.1 External Interlock (FAIL-SAFE)
A closed circuit must be provided between TB1-1 and TB1-2
before the transmitter will operate. Opening or interrupting this
circuit will cause the transmitter primary power contactors to
open and remove AC power from the high voltage power supply
(230 VDC supply). As long as the circuit remains open, the
transmitter cannot be turned on again. This is an INTERLOCK
function in the transmitter, and is intended for remote control
FAIL-SAFE applications, and other system interlock applications where transmitter turn on must be prevented.
The External Interlock should NOT be used to interrupt the
transmitter RF output for phasor or antenna pattern switching;
the PA TURN PA OFF connection (at TB1-21 and TB1-23)
should be used for that purpose. The voltage at TB1-1 and TB1-2
is 24 VAC with +30 VDC to ground. External interlock contacts
and wiring should be rated for 1 ampere AC current.
2.9.2 “OFF” Function (Remote “OFF” Control)
The OFF control removes AC power to the high voltage power
supply (the 230 VDC supply) by deenergizing the transmitter
AC power contactors. When the transmitter has been turned off
with the OFF control, it will not turn on again until a HIGH,
MEDIUM or LOW power button or remote control command is
given. The remote OFF control requires a contact closure, or
transistor turn-on, of 100 milliseconds or more. The OFF control
2-12
a. “OFF” Control
Applying a voltage momentarily (for 100 milliseconds or more)
to the remote “OFF” control inputs, TB1-33 and TB1-35, turns
the transmitter off by de-engergizing high voltage supply primary contactors through turn-on/turn-off logic, and resetting
transmitter logic. This input is in parallel with the transmitter
“OFF” push-button switch. The transmitter remains OFF until a
LOW, MEDIUM, or HIGH control input is provided.
a. “PA Turn OFF”
Applying a voltage to the “PA Turn-Off” control inputs, TB1-21
and TB1-23, turns off RF output, in less than a millisecond, by
turning off all PA RF amplifier modules through the modulation
section. No contactors operate for this function. The PA modules
remain OFF as long at the control voltage at the “PA Turn-Off”
control input is present, but as soon as the voltage is removed the
modules come ON again, under control of the modulation section. The “PA Turn Off” function is the same as turning the PA
ON/OFF switch on the Controller board “OFF,” then “ON”
again.
a. External Interlock
A closed circuit between External Interlock terminals TB1-1 and
TB1-2 must be provided to complete the circuit for the high
voltage power supply contactor coils. Breaking the External
Interlock circuit interrupts the contactor coil circuit and causes
the contactors to de-energize, turning off high voltage. As long
as the external interlock circuit is open, the transmitter cannot be
turned on again. If the external interlock is opened then closed
again, the transmitter will remain off and must be turned on
manually using LOW, MED, or HIGH push buttons or control
inputs.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
2.9.5 Use of OFF, PA Turn OFF, and External In-
terlock Functions
Remote Meter Readings
a. “OFF” Control
Use for normal transmitter turn-off, for example, at the end of
the operating day.
a. “PA Turn OFF”
Use to remove RF output during antenna pattern switching or for
other RF switching operations. Because the transmitter’s RF
output returns as soon as the “PA Turn Off” control input voltage
is removed, PA Turn Off MUST NOT be used for fail-safe or
safety interlock purposes]
a. “External Interlock”
Use for FAIL-SAFE and for safety interlocks on any enclosure
which would permit contact with transmitter RF output, such as
phasors or antenna switching equipment.
2.9.6 Transmitter Turn ON
The DX-10 does not have a separate “ON” switch. The transmitter comes ON at the desired power level (Low, Medium or High)
when a momentary remote control input (at least 100 milliseconds long) is provided at the LOW, MEDIUM, or HIGH terminals on TB1. If the transmitter is already ON, providing another
of these inputs will simply change power level without interrupting RF output.
2.9.7 Raise/Lower
A RAISE input will cause transmitter power output to increase
for as long as the control input is provided, or until the transmitter
power output reaches the maximum power limit. A LOWER
input will cause transmitter power output to DECREASE for as
long as the control input is provided, or until the power output
reaches zero.
NOTE
When remote control and monitoring is used, delays IN REMOTE CONTROL SYSTEM data transmission can delay the remote output power reading while the RAISE or LOWER controls
are being operated, and the remote output power reading can
continue to change for a short time after the RAISE or LOWER
command is stopped.
2.9.8 “Forward” and “Reflected” Power, Remote
Meter Readings
These outputs correspond to the transmitter “forward” and “reflected” power meter indications. Note that the transmitter power
meter scale is not linear. The voltage outputs at Forward remote
output TB1-3 and Reflected remote output TB1-4 are proportional to the transmitter RF output voltage, and are proportional
to the SQUARE ROOT of the power.
Both remote power outputs will be approximately 3.4 VDC at
10 kW reflected power, into a high impedance. (This signal
VOLTAGE will vary with the square root of the monitored
power).
03/16/2009
2.9.9 Bandpass Filter VSWR and Antenna VSWR,
These are UNCALIBRATED, relative readings from the VSWR
phase detectors on Output Monitor board A27, as follows:
a. Bandpass Filter VSWR (BPF VSWR) corresponds to the
“Detector Null (Filter)” reading on the transmitter front
panel multimeter.
b. Antenna VSWR corresponds to the “Detector Null (Antenna) reading on the transmitter front panel multimeter.
A mismatch in the antenna system or Tee Matcher will cause the
Antenna VSWR reading to increase. A change in the Bandpass
filter/output network will cause “Bandpass Filter VSWR” reading to increase. Reflected Power is a calibrated reading. Use
Reflected Power for normal remote readout. ANTENNA VSWR
is an uncalibrated, relative reading, but is more sensitive than
“Reflected Power.”
2.9.10 RF Drive estimate, Remote Meter Reading
(at TB1-9)
This is an UNCALIBRATED sample of the RF drive to the RF
Power Amplifier, and corresponds to the “Relative RF Drive”
position on the transmitter front panel multimeter.
2.9.11 Monitor Signal
+22 VDC," -22VDC, +8 VDC, and -8VDC (REMOTE METER
READINGS). These voltages are samples of the unregulated
voltages from the low voltage power supply, and are the same
as the corresponding front panel multimeter readings.
2.9.12 Remote Status Indications
These correspond to lighted push buttons or to RED indications
on the transmitter’s status panel.
2.9.13 RF Combiner Crowbar not Operational
This status output is not used on the DX-10.
2.10 Pre-Turn ON Checks; Mechanical
When installation has been completed, and before applying
primary power for the first time, the transmitter should be
inspected again, including checks in the following paragraphs
and in the paragraphs on Electrical pre-turn on checks.
Although appropriate packaging and shipping precautions are
taken before the equipment leaves the factory, hardware sometimes works loose during shipment. The transmitter should be
checked for any debris, loose hardware and loose connections
before applying primary power. Pre-turn on checks and inspection should include:
a. Check for debris and loose hardware, both in the transmitter and in the AC power panel.
b. Check for loose connections, in particular at the following:
Filter capacitors, High voltage and low voltage supply
rectifier diodes, Output network clips, insulators and hard-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-13
ware, High voltage supply transformer and the Low voltage supply transformer.
c. Check ribbon cable connectors. Ensure that cable connectors are properly locked into their printed circuit board
connectors.
d. Ensure that output network connections and coil taps are
tight, especially at high current points. (Over tightening
can strip threads or break bolts, especially where brass
hardware is used).
Table 2-6
Minimum Recommended Control and Status Functions
for Remote Control
CONNECTION
FUNCTION
CONTROLS:
1. TB1-22, TB1-24
HIGH power control
2. TB1-26, TB1-28
MEDIUM power control
3. TB1-30, TB1-32
LOW power control
4. TB1-25, TB1-27
LOWER control
5. TB1-29, TB1-31
RAISE control
6. TB1-33, TB1-35
OFF control
7. TB1-38, TB1-40
OVERLOAD RESET
METERED PARAMETERS:
1. TB1-3
FORWARD POWER
2. TB1-4
REFLECTED POWER
3. TB1-5
SUPPLY CURRENT
4. TB1-6
SUPPLY VOLTAGE
(Use TB1-10 for ground return for remote metering outputs).
OVERLOAD AND FAULT INDICATIONS:
1. TB2-9
LOAD VSWR occurred
2. TB2-24
SUPPLY VOLTAGE overload
3. TB2-25
SUPPLY CURRENT overload
4. TB2-33
Type 3 FAULT
(Use TB2-19 or TB2-20 for ground return).
STATUS INDICATIONS:
1. TB1-15
LOWER indication
2. TB1-16
HIGH POWER indication
3. TB1-17
RAISE indication
4. TB1-18
MEDIUM POWER indication
5. B1-20
LOW POWER indication
(Use TB1-13 or TB1-14 for ground return).
ADDITIONAL DESIRABLE STATUS INDICATIONS:
10. TB2-22
EXTERNAL INTERLOCK
OPEN indication
11. TB2-26
UNDER-DRIVE fault
12. TB2-27
OVER-DRIVE fault
13. TB2-28
AIR OVERLOAD
14. TB2-29
HIGH VOLTAGE SUPPLY
FAILURE
15. TB2-30
CURRENTLY UNDER
LOCAL CONTROL
16. TB1-21,23
PA OFF
The “PA OFF” control input is normally connected to the
Phasor or Antenna Switching control unit for antenna pattern
switching.
2-14
e. Ensure that no shipping ties, blocks, or tape remain.
2.11 Pre-Turn ON Checks; Electrical
Before initial turn-on, ensure that the following items have been
completed:
a. A ground strap must be properly connected between the
transmitter and the station earth ground.
b. AC input wiring must be properly connected and connections must be tight.
c. The transmitter RF output must be properly terminated
with a suitable load capable of handling rated output
power. This can be either an antenna system or a dummy
load.
d. Fail-safe interlocks must be satisfied.
e. Audio input is properly connected.
f. Monitoring equipment is properly connected.
g. The Controls and Indicators section of the Operator’s
Technical Manual or in section 3, Operation, in this technical manual should be read and understood.
h. The REMOTE/LOCAL switch on the transmitter’s Status
Panel should be in the LOCAL mode.
2.12 Initial Turn On Procedures
WARNING
IF YOU MUST ENTER ANY PART OF THE TRANSMITTER EXCEPT
THE CENTER FRONT NON-INTERLOCKED COMPARTMENT,
TURN OFF THE TRANSMITTER BY DEPRESSING THE “OFF”
BUTTON, SET THE REMOTE/LOCAL SWITCH ON THE STATUS
PANEL TO “LOCAL,” AND REMOVE PRIMARY POWER BY TURNING THE WALL DISCONNECT SWITCH OFF. BEFORE REMOVING PANELS OR OPENING DOORS, VERIFY THAT THE HIGH
VOLTAGE SUPPLY IS DISCHARGED BY CHECKING “SUPPLY
VOLTS” ON THE FRONT PANEL MULTIMETER. GROUNDING
STICKS ARE PROVIDED INSIDE THE TRANSMITTER AND
SHOULD BE USED TO TO ASSURE THAT ALL HIGH VOLTAGE
HAS BEEN REMOVED.
CAUTION
WHEN WORKING IN THE FRONT NON-INTERLOCKED COMPARTMENT, BE CAREFUL NOT TO GROUND ANY CONNECTIONS
WHICH ARE STILL ENERGIZED. THIS INCLUDES ALL LOW
VOLTAGE CIRCUITS IF THE LOW VOLTAGE SWITCH S11 HAS
NOT BEEN SET TO “OFF” POSITION.
CAUTION
IF ANY ABNORMALITIES ARE ENCOUNTERED IN THE FOLLOWING STEPS, STOP THE PROCEDURE, REMOVE ALL POWER, AND
REFER TO TROUBLESHOOTING SECTION OF DX-10 MAINTENANCE TECHNICAL MANUAL.
The initial turn on sequence provides checks or adjustments for
the following items:
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
a. Normal Low Voltage supplies operating.
b. Correct fan rotation.
c. Correct Driver operation.
d. Matching the transmitter to the load.
e. Correct operation at various power levels.
f. Setting RF Monitor levels.
g. Battery Backup for controller.
h. Log normal meter readings.
i. Modulation check and level set.
j. On Line and final matching check.
If all pertinent Installation Procedures up to this point have been
completed, the transmitter is ready to begin powering up per the
following sequence:
2.12.1 Low Voltage Power Supplies Check
Find the packet shipped with the transmitter entitled “Factory
Test Data.” Factory data for the four Low Voltage supplies
(under no carrier or low power conditions) will be listed and is
the reference for the following observations.
Use the following procedure to check the Low Voltage power
supplies:
a. Ensure that the transmitter’s REMOTE/LOCAL switch is
in the LOCAL position.
b. Ensure that Low Voltage Power Supply rocker switch S11
is in the ON position. This switch is located in the non-interlocked compartment, at the bottom of the compartment’s right hand side.
c. Switch the front panel multimeter to the -8 VDC position.
d. Apply AC power to the transmitter at the main disconnect
wall switch. DO NOT TURN THE TRANSMITTER ON
AT THIS TIME; DO NOT OPERATE THE HIGH, MEDIU M, OR LOW POWER PU SH-BUTTON
SWITCHES. Low voltage supplies come on when AC
power is applied to the transmitter.
e. All transmitter front panel Status Panel indicators should
be lit, either red or green (except for the Remote LED,
which will not be illuminated when in the LOCAL position). Indicators are bi-color LED’s (except for Local and
Remote indicators, which are single LED’s).
f. Read the multimeter, on the scale indicated for “-8 VDC”
(this is the 0-10 scale). The voltage reading should be
within +5% of the factory recorded value, on the Factory
Test Data Sheet, for “-8 VDC.” Switch the multimeter to
+8, -22, and +22 VDC positions and check the readings
against the factory test data.
NOTE
IF THE READINGS ARE NOT WITHIN 5% OF THE FACTORY
TEST READINGS, REMOVE AC POWER AT THE WALL DISCONNECT SWITCH AND REVIEW THE AC POWER CONNECTIONS TO T1 AND T2.
g. With AC power applied (but with the transmitter still
OFF), open the transmitter’s center front door and locate
03/16/2009
the RF multimeter inside the compartment, on the compartment’s right side wall.
h. Switch to each of the following three parameters and check
them against the factory test data:
1. PREDRIVER IDC (0-3 scale).
2. PREDRIVER VDC (0-10 scale X 10).
3. REGULATOR +15 VDC (0-3 scale X 10).
2.12.2 Fan Rotation Check
The blower motor is a 3-phase motor, and correct rotation must
be verified, and, if necessary, two leads must be interchanged at
the blower motor fuses to obtain correct rotation. Use the following procedure:
a. Flip the “PA ON-OFF” toggle switch, S5 on Controller
Board (A38), to the OFF position (switch handle UP). This
manually holds the PA “OFF” irrespective of any front
panel or remote commands. PA OFF switch S5 is at the
bottom center of the Controller board, which is on the back
of the transmitter’s non-interlocked front door.
b. Depress the green LOW Power button on the front of the
transmitter. The button’s internal lamp should illuminate,
you should hear high voltage step-start contactors K1 and
K2 operate, and the blower should start. (If not, check
Interlock Status indicators and interlocks).
c. If there is insufficient air pressure, the transmitter may turn
off again after a few seconds, and the AIR INTERLOCK
indicator will indicate RED. If so, simply depress the LOW
Power button again to start the fan when you are ready to
continue.
d. Depress the red OFF button.
e. IMMEDIATELY remove the center panel from the back
of the transmitter, and observe the coasting fan’s direction
of rotation. DO NOT TURN THE TRANSMITTER “ON”
WITH THE PANEL OPEN. (The fan is located at the
bottom of the right side of the center rear compartment, as
viewed from the back of the transmitter).
f. The fan should be coasting in a CCW (Counter-clockwise
direction) and a slight positive breeze should be felt blowing from it. (Air flow should be into the center compartment).
g. If the rotation is correct, reinstall the center cover panel
and proceed as indicated below.
h. If Rotation is NOT Correct:
1. Turn the Wall Disconnect Switch OFF
Remove the rear panel from the power supply compartment.
1. Disconnect and interchange ANY TWO of the three
wires to the blower motor, at the top of the blower motor
fuses F7, F8 and F9 (wire numbers 46, 47, and 48).
These three fuses are located on the outside wall of the
power supply compartment, at the back of the compartment about a third of the way down from the transmitter’s top. (Interchanging any two of the three wires to
a three phase motor will reverse its direction of rotation).
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-15
2. Reinstall the power supply compartment back door,
then turn the wall disconnect switch ON to reapply AC
primary power to the transmitter again.
3. Re-check the fan’s direction of rotation.
a. Assuming that the fan rotation is now correct, ensure that
rear panels are all in place, and turn the transmitter on by
depressing the green LOW POWER button.
b. When the transmitter is first turned on, the “AIR” interlock
light will extinguish for 2 or 3 seconds. It will then come
back on, as follows:
1. GREEN: Air pressure is okay.
2. RED: Air pressure FAULT. The fault will also turn the
high voltage off again.
An “air pressure fault” indicates insufficient air. Most likely
causes are fan rotation incorrect, or the back panel is not installed
or fastened down at all points.
mum DETECTOR NULL (ANTENNA) reading on the front
panel multimeter.
2.12.3 RF Driver Operation Check
With the transmitter still turned on in the LOW POWER mode,
and the PA OFF switch still OFF (S5 on the controller board
OFF), check the following:
Use the following procedure to fine-tune C101:
a. On the front panel multimeter, use the selector switch to
select and read PA SUPPLY VOLTAGE. Compare this
reading with the factory test data.
b. If the PA SUPPLY VOLTAGE is not within 5% of the
factory test reading, turn the transmitter OFF, remove all
primary power by turning the wall disconnect switch OFF,
and check high voltage supply transformer T1 primary
tapping. If PA SUPPLY VOLTAGE agrees with the factory test data, continue.
c. On the front panel multimeter, use the selector switch to
select and read RELATIVE RF DRIVE. Compare this
reading with the factory test data.
d. On the RF MULTIMETER inside the non-interlocked
front compartment, read the following parameters and
check each against the factory test data:
1. DRIVER +VDC
2. DRIVER IDC
3. DRIVER SECTION 1A VDC
4. DRIVER SECTION 1B VDC
2.12.4 PA Checkout
When low voltage supply voltages, high voltage supply voltages,
and RF driver parameters have been confirmed, you should read
the following paragraphs, then continue with the transmitter
tuning procedure that follows the descriptions.
In the following steps, you will first adjust “TUNE” and
“LOAD” controls, then increase power and repeat these steps.
You will also check transmitter RF output.
The “TUNING” and “LOADING” controls on the front of the
transmitter do NOT adjust “tuning” and “loading” of the transmitter in the traditional sense. They are adjusted for minimum
reflected power (a coarse, or broad indication) and for a mini-
2-16
CAUTION
DO NOT ADJUST “TUNING” AND “LOADING” FOR ANY OUTPUT
FORWARD POWER OR SUPPLY CURRENT CONDITION. ADJUST
FOR MINIMUM REFLECTED POWER AND MINIMUM ANTENNA
DETECTOR NULL INDICATIONS.
“Tuning” and “Loading” are impedance matching adjustments,
provided for your convenience, to match the load impedance to
the 50 ohm output impedance of the transmitter’s bandpass
filter/output network. They are part of a “Tee Matcher,” an
impedance matching Tee network. “Tuning” and “Loading”
adjust reactance and resistance, respectively, at the 50-ohm point
where the directional coupler and VSWR phase detectors are
located.
2.12.4.1 Tuning, at about 1 Kilowatt Output
a. Turn the transmitter ON by depressing the LOW POWER
button.
b. Flip PA ON/OFF switch S5 on the Controller board to the
ON position. There should be no RF power output, but the
CURRENT meter on the front of the transmitter will
indicate about 2.5 to 4 amperes. This is RF driver current.
Note- the meter reads the total High Voltage Supply current, not just PA current. When figuring PA current,
subtract the noted driver current from the total current.
c. Switch the front panel multimeter switch to DETECTOR
NULL (ANTENNA).
d. Switch the Power Meter switch to FORWARD.
e. Depress and hold the RAISE button. Observe the POWER
meter for slowly increasing power output. The CURRENT
meter indication will also increase. Continue to hold the
RAISE button until forward power reaches approximately
1 kW.
f. Matching the Load (TUNE and LOAD Controls) with the
transmitter’s power output still at about 1 kilowatt, continue with the following steps:
g. Note the Antenna Detector Null reading on the front panel
multimeter. The selector switch must be in the DETECTOR NULL (ANTENNA) position.
h. If the antenna is perfectly matched to the 50 ohm transmitter output, it will read ZERO. If it is not zero, alternately
adjust “TUNING” and “LOADING” controls to reduce
the Antenna Detector Null reading. Continue adjusting
Tuning and Loading alternately, until the Antenna Detector Null reading is zero.
(Recall that when you adjust the TUNING and LOADING
controls, you are actually adjusting reactance and resistance at
the 50 ohm output point).
a. Check Multimeter Readings at 1 KW output. Use the
RAISE and LOWER buttons to set the transmitter output
power to exactly 1 kW. Check all meter readings, including all readings on both the front panel multimeter and the
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
RF multimeter inside the non-interlocked compartment,
and compare them with the factory test data.
2.12.4.2 Tuning and Verifying Correct Operation at High
Power
When you have completed tuning and verified meter readings at
1 kW, continue as follows:
a. Depress the MEDIUM power button. Use the RAISE
control to bring the power output to about 5 kilowatts.
b. Check the DETECTOR NULL (ANTENNA) meter reading. Readjust the Tee network (Tune and Load Controls)
if necessary, to null the reading.
c. Switch the POWER meter selector switch to REFLD
(Reflected) and confirm that reflected power is zero. When
the Antenna Detector Null reads zero, reflected power will
also read zero.
d. Set the power output to exactly 5 kilowatts, using the
RAISE and LOWER controls. Check all meter readings
against the factory test data.
e. Depress the HIGH power button, and raise the output
power to 10 kilowatts.
NOTE
Note that antenna impedance should not change as power
changes. However, typical air cooled resistor loads may change
their impedance by as much as 2:1 from cold to hot (for example,
from 1 kW to 10 kW). As the load impedance changes, the Tee
Matcher adjustments for an Antenna Detector Null will also
change.
f. When the transmitter is correctly tuned at 10 kilowatts
output, check all meter readings against the factory test
data.
NOTE
g. The Test Data reading for PA amps is the meter reading
minus the no-power-out ampere reading.
You have now completed initial transmitter tune-up. During
normal operation, the TUNE and LOAD controls are adjusted as
in this procedure, for a minimum Antenna Detector Null reading.
2.12.5 Modulation Monitor; Setting Sample Levels
First, the modulation monitor sample is set for the proper level
for your modulation monitor At the LOWEST operating
POWER, by moving a tap on modulation sample inductor L107.
When Low Power sample level has been set, two controls on
Output Monitor board A27 (in the non-interlocked front compartment) are adjusted to set the sample level at MEDIUM and
HIGH power to the same voltage.
The maximum safe modulation monitor sample voltage is 10
volts rms, into a 50 ohm load. The coaxial cable from the
transmitter’s modulation monitor sample output (J5 on the Output Monitor Board, A27) should be terminated with a 50 ohm
termination. This termination should have at least a three watt
rating.
2.12.5.1 Setting Modulation Monitor Sample Level
Use the following procedure:
03/16/2009
a. Set the LOW power output of the transmitter to the lowest
power that will be required for normal operation or to 1
kW, whichever is lowest.
b. Measure the RF voltage level at the monitor. If the level
must be increased or decreased to meet modulation monitor input voltage requirements, the tap on L107 must be
moved.
c. Moving the tap on L107, Modulation Monitor Sample Coil
(if Required):
d. Turn the transmitter OFF and remove all AC power from
the transmitter by turning off the wall disconnect switch.
e. Remove the back panel from the output network compartment.
f. L107 is the coil mounted on the inside of the transmitter’s
top panel. L107 has an adjustable tap, near the grounded
end of the coil. To DECREASE the sample voltage, move
L107’s tap closer to the grounded end of the coil. To
INCREASE the sample voltage, move L107’s tap away
from the grounded end of the coil.
g. Move the tap 1/4 turn in the desired direction (see step e.
above). Be careful when positioning the tap clip, so that
neither the clip or its screw short to adjacent turns.
h. Replace the output network compartment’s rear panel,
turn on the wall disconnect switch, and depress the LOW
power switch.
i. Measure the sample voltage again. If necessary, repeat the
above steps, moving the tap on L107 in 1/4 turn increments
until the desired sample voltage is arrived at, at LOW
power. ENSURE THAT PRIMARY POWER IS
TURNED OFF, AT THE WALL DISCONNECT
SWITCH, BEFORE REMOVING THE REAR PANELS.
j. Setting Medium Power Sample Level. When the LOW
power sample level is satisfactory, and all rear panels are
in place again, continue with the following steps:
k. The MEDIUM power modulation monitor sample adjustment is “MED PWR MON ADJ” rheostat R7, on Output
Monitor board A27. Turn this control fully CCW (Counterclockwise), so that the sample output does not suddenly
increase when increasing transmitter power output.
l. Turn the transmitter on at MEDIUM power, or, if the
transmitter is already on, depress the MEDIUM power
level push-button switch, then use the RAISE and
LOWER controls to set the normal MEDIUM power output.
m. Adjust “MED PWR MON ADJ” rheostat R7 on Output
Monitor board A27 until the sample voltage at the modulation monitor is the SAME as it was in the LOW power
position. This rheostat can be adjusted while the transmitter is operating.
n. Turn “HIGH PWR MON ADJ” rheostat R8, also on Output Monitor board A27, fully CCW.
o. Depress the HIGH power push-button to operate the transmitter in its High Power mode, and use the RAISE and
LOWER push buttons to set the output power to the
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-17
highest power used for routine operation. (This may be
more than 10 kilowatts in some installations, because of
power losses in the antenna system. In the United States
and some other countries, your station license should
specify required transmitter carrier power).
p. Adjust “HIGH PWR MON ADJ” rheostat R8, on Output
Monitor board A27, for the same RF sample voltage as
already set at LOW and MEDIUM powers.
q. Switch between LOW, MEDIUM, and HIGH power to
verify that the modulation monitor sample is the same for
all three power levels. If necessary, readjust R7 or R8 so
that all sample voltages are the same.
r. If the modulation monitor has not been connected yet,
connect the modulation monitor sample coaxial cable to
the modulation monitor input.
2.12.6 Controller;Battery Backup
If Battery Backup for the Controller’s power mode and power
level memory is desired, the batteries should now be installed.
(Recall that the capacitor backup in the transmitter will retain
memory for at least two hours, and that batteries provide indefinite backup).
2.12.6.1 Installing Batteries
Check battery polarity on the holder, and simply insert 3 AA size
alkaline cells in the battery holders on the Controller board.
(Carbon-zinc or other primary cells can also be used. Do NOT
use rechargeable batteries, such as NiCad batteries.) The batteries should be installed only when the One Farad energy storage
capacitor is charged, so that charging current from the batteries
doesn’t shorten battery life. The batteries can be installed while
the transmitter is ON, because with the capacitor charged a diode
is reverse biased and no battery current flows.
2.12.7 Modulation Check
The transmitter is now ready for modulation. During this check,
you should monitor the RF envelope by connecting an oscilloscope in parallel with the modulation monitor RF input.
Check for proper modulation at various power levels, as follows:
a. Patch an audio oscillator into the transmitter’s audio input.
b. Turn the transmitter on at LOW power. Begin by applying
low levels of audio (a sine wave at about 400 Hz to 1 kHz),
while observing the modulation monitor and the oscilloscope.
c. Increase the oscillator output until modulation level is
about 50%.
d. Observe the modulated RF signal on the oscilloscope; the
modulation envelope should be a smooth sine wave, with
no steps, notches, or other distortion. (If a distorted envelope is observed, check the audio oscillator output with the
oscilloscope before assuming there is a transmitter problem. Sometimes, defective test equipment is the problem
rather than the equipment being tested).
e. Switch to MEDIUM power. The transmitter will maintain
the same modulation level. Again, observe the modulated
2-18
f.
g.
h.
i.
RF signal on the oscilloscope. The modulation envelope
should still be a smooth sine wave.
Switch to HIGH power. The modulation level will still be
the same. Once more, observe the modulated RF signal.
The modulation envelope should still be a smooth sine
wave.
Increase the modulation to 95% negative peak modulation.
Observe the wave form again.
Verify that output power and modulation level are the
same as used for the factory test, and adjust if necessary.
Check all meter readings against the factory test data
sheets. Meter readings should be close to factory readings
for the same High Power level and modulation level.
Note that the front panel “CURRENT” meter reading
depends on power output AND modulation level. This
meter reads the average current returning to the high
voltage supply, including PA and RF driver current. Because PA voltage is fixed, PA current depends on total
transmitter power output, which varies with modulation.
2.12.8 Audio Gain Adjustment
The Audio Input sensitivity of the DX-10 transmitter can be
adjusted with the AUDIO GAIN ADJ control on the Analog
Input board, so that audio input levels of -10 dBm to +10 dBm
at 600 ohms will produce 100% modulation. Use the following
procedure to for this adjustment:
a. Determine the station’s reference audio level for 100%
modulation. (Typical levels are 0 dBm or +8 dBm, but the
DX-10 can accommodate reference levels from -10 dBm
to +10 dBm at 600 ohms.)
b. Switch the transmitter to MEDIUM power. Set the sine
wave audio level into the transmitter to the station’s reference value for 100% modulation. (If you are using an
output level meter on the audio signal generator, be sure
that the generator is operating into the proper impedance,
because some audio signal generator’s meters are accurate
only with the correct load.)
c. Locate the “Audio Gain Adjust” control, on the Analog
Input Board. This control is a screwdriver adjustment, R15
on Analog Input Board A35. (Its location is shown as
reference number 3 on Figure J-1, Analog Input Board
Controls and Indicators, in section J of this technical
manual). The Analog Input board is just below the Output
Monitor board, on the left side wall of the transmitter’s
front non-interlocked compartment.
d. Adjust the “Audio Gain Adjust” so that modulation level
is 100%, as read on the modulation monitor. This completes audio input level adjustment.
2.12.9 Recording Normal Meter Readings
We strongly recommend that a permanent record of ALL meter
readings be made, with carrier only (no modulation) and with
modulation at one or more levels (-95% should be one level).
The form at the end of this section provides an outline. Data
should be taken while operating into a dummy antenna (dummy
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
load) if one is available, because that is a repeatable set of
conditions.
2.12.10 Final Matching Into Antenna
PERFORM THESE STEPS, EVEN IF YOUR TRANSMITTER
WAS INITIALLY TURNED ON USING YOUR ANTENNA
SYSTEM AS A LOAD.
If the transmitter was initially turned on and tested into a dummy
load, as recommended, you should now switch to the antenna.
Also, there are shorting straps connected across the Tuning and
Loading inductors which will be removed at many operating
frequencies, after tuning into the antenna. Turn the transmitter
OFF and switch the transmitter RF output from the dummy load
into the antenna, then continue with the following steps:
a. With the transmitter connected to the antenna, turn the
transmitter on at LOW power. Check the Antenna Detector Null, and, if necessary, adjust the Tee Matcher using
the LOADING and TUNING controls to obtain a minimum Antenna Detector Null reading. (Antenna system
input impedance is usually not the same as the dummy load
impedance).
b. Switch to HIGH power and recheck the impedance match,
re-adjusting slightly for an Antenna Detector Null if necessary.
c. Turn the transmitter OFF.
WARNING
ENSURE ALL PRIMARY AC POWER IS REMOVED FROM THE
TRANSMITTER AND THAT A GROUNDING STICK HAS BEEN
USED TO DISCHARGE ANY AC OR RF VOLTAGES WHERE
POWER HAS BEEN APPLIED BEFORE PERFORMING THE FOLLOWING STEPS.
d. Remove the back panel on the output network compartment.
e. Inspect the TUNING and LOADING variable inductors
(L103 and L104, in the top section of the output network
compartment). Check the position of the rotary contact on
both inductors. If the rotary contact is within 5 turns (about
1 inch) of the BACK of one or both coils, a shorting strap
across the unused turns must be removed. If BOTH coils
have AT LEAST 5 TURNS remaining between the rotary
contact and the back of the coil, continue with Replacing
the Rear Panel.
2.12.10.1 Removing The Shorting Straps On L103 and L104
if required.
a. If the rotary contact on either coil (L103 or L104) is closer
than 5 turns (about 1 inch) from the back of the coil,
REMOVE the coil shorting strap. The shorting strap is a
flat copper strap about 1/2 inch wide, which goes from the
back of the coil winding to a terminal on the front of the
coil. Save the strap; it should be re-installed again if the
antenna load impedance is changed at a later time so that
the rotary contact is further forward on the coil. (Typically,
at the high end of the broadcast band, both shorting straps
03/16/2009
will be left in place; at the low end of the broadcast band,
both shorting straps may need to be removed).
b. After removing the shorting straps, ensure that connections to the coil are tight again.
c. If the Strap was Removed from one or both coils: Removing the shorting strap or straps will change the inductance
of the variable inductor or inductors slightly, requiring
some readjustment of TUNING and LOADING. Proceed
as follows:
1. Replace the output network compartment’s rear panel,
then reapply AC power, turn the transmitter on at LOW
power, and adjust TUNE and LOAD controls as required to achieve a null indication in the Antenna
Detector Null reading.
2. Switch to HIGH power, and make small adjustments in
TUNING and LOADING, if required, to obtain a minimum Antenna Detector Null reading again.
2.12.10.2 Finishing Up
a. REPLACE THE REAR PANEL, if it is not already in
place. Verify that all 1/4 turn fasteners on all three rear
panels are locked. The transmitter is now ready for normal
service.
2.12.11 Optional Audio Phasing
This is not a transmitter check, rather, it is a system check. The
DX-10 is capable of positive peak modulation of +125% or
greater at 11 kW carrier power, and even higher positive peak
modulation at 10 kW or less. An audio phasing check may also
be included in manuals for audio processing equipment; if so,
you can use that check instead of the following. In the United
States and many other countries, positive peak modulation up to
+125% is permitted. If regulations at your location permit, and
you have audio processing equipment with asymmetrical output,
you may wish to verify that your audio input is phased correctly.
Proceed as follows:
a. You will need a program source or audio frequency generator with asymmetrical output, audio processing equipment capable of providing positive peaks over +100%, and
a modulation monitor with a negative 100% peak flasher
and an adjustable positive peak flasher. (Ideally, an audio
generator with an asymmetrical audio frequency output is
ideal for this check, but is not available at most stations).
b. Turn the transmitter on, at any power level, and modulate
with asymmetrical audio or with program. Adjust the
program level so that negative peaks just reach -100%.
c. Observe positive peak modulation levels.
1. If positive peaks are about 100%, you don’t have a
program source with higher positive peaks than negative peaks, or possibly your processing equipment is not
adjusted properly.
2. If positive peaks are LESS than 100%, try reversing the
two audio signal leads, either at the audio output supplying the transmitter or at the transmitter audio input
terminals.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-19
3. If positive peaks are GREATER than 100%, your audio
input phasing is correct.
2-20
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Table 2-7
Transmitter Meter Reading Log at Initial Turn-On
FREQUENCY
DATE
1KW
5KW
10KW
1KW
5KW
10KW
1KW
5KW
10KW
AUDIO MODULATING
FREQUENCY
MODULATION %
CARRIER POWER
PA CURRENT
FRONT PANEL MULTIMETER
-8V
+8V
-22V
+22V
RELATIVE RF DRIVE
DET. NULL (ANTENNA)
DET. NULL (FILTER)
PA SUPPLY +VDC
RF MULTIMETER
PREDRIVER IDC
PREDRIVER +VDC
REGULATOR +15VDC
DRIVER +VDC
DRIVER IDC
DRIVER SECT 1A+VDC
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-21
Blower Motor
Fuses F7, F8, F9
AC Power
Input
TB5
(under cover)
LV Transformer
T2 Primary Connection
Block
Grounding
Terminal
E14
Modulation Monitor
Sample Coil
L107
C101
C102
HV Transformer
T1 Primary
Connections
Grounding
Block
E14
Blower
B1
Figure 2-3
DX-10, Installation Information, Rear View
2-22
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
RF Output Connector
1-5/8" EIA flange
C101 Adjustment
Access Hole
Wire Entrance
2 inch round
openings
Figure 2-4
DX-10, Installation Information, Top View
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-23
2 inch round
wiring entance
openings
RF Multimeter
A23M1
2 inch round
wiring entance
openings
Low Voltage
Power Supply
Switch S11
Figure 2-5
DX-10, Installation Information, Front View with Doors Open
2-24
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
TB1
Remote Control
Connection Points
TB2
Audio Input
Connection Point
TB3
External Interface
Board A28
RF Multimeter
A23M1
RF Multimeter
Selector Switches
Frequency Monitor
Output J5
Optional External
Oscillator Input
J2
Oscillator
Board
A17
Figure 2-6
DX-10, Installation and Checkout Information, View Showing Right Side of Front Non-interlocked Compartment
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
2-25
Power Meter M3
Supply Current
Meter M1
Multimeter M2
Modulation Monitor
Level adjustments
(High and Medium
Power)
Output Monitor
Board A27
Modulation Monitor
Sample Output J5
Analog Input
Source Impedance
Shunt, J1, J2, J3
Analog Input
Board A35
Controller
Board A38
Optional
Back-Up
Batteries
"PA OFF"
Switch S5
Figure 2-7
DX-10, Installation and Checkout Information, View Showing Left Side of Front Non-interlocked Compartment
2-26
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section III
Operation
3.1 Introduction
This section of the DX-10 Technical Manual contains information on transmitter operation for the maintenance engineer or
technician.
3.2 Operating Procedures
These procedures describe normal daily operation of the DX-10
AM Transmitter, including:
a. Daily preoperational checkout (for local control)
b. Daily preoperational checkout (for remote control)
c. Transmitter turn-on procedures
d. Transmitter turn-off procedures
It is important that the operator be aware of normal transmitter
operation and performance, and note any changes or fault indications. Changes in operation may indicate a need for maintenance or corrective action before more serious problems
develop. Consult the Maintenance and Troubleshooting Section
VI of the manual for more information.
WARNING
ALL SERVICE SHOULD ONLY BE PERFORMED BY QUALIFIED
PERSONNEL. DANGEROUS VOLTAGES MAY BE PRESENT INSIDE WHEN DOORS ARE OPEN.
Normal operation and monitoring of the DX-10 Transmitter is
accomplished through front panel controls, meters, and indicators. Normal operating controls may be operated by remote
control, and monitoring and status indications are also available
through a remote control system. If remote control of the transmitter is used, the station chief engineer or qualified technical
staff member should provide instructions for operators on its use.
3.3 Daily Preoperational Checkout (Lo-
Check the status indicator panel. This panel uses bicolor LED
indicators, which may be either red or green. If primary power
is applied and the transmitter is ready for operation, all the status,
interlock, and overload LED’s will be green. If no LED’s at all
are lit, there is probably no primary AC power to the transmitter.
If any LED’s are red, note which indicators are red so that
information may be entered into the station maintenance log,
then press the “RESET” button. All indicators should change to
green when the RESET button is pushed and released. If any
indicators are still red after operating the RESET, refer to paragraph “Fault status indications will not clear when reset.” If all
indicators remain green when the RESET button is pushed and
released, continue with transmitter turn on procedure, below.
(Note that the red REMOTE status indicator is not a fault
indication, and indicates that the transmitter may be operated by
remote control equipment.)
3.4 Daily Preoperational Checkout (Re-
mote Control)
Check the transmitter maintenance log to make sure that maintenance performed on the transmitter, or other abnormal conditions, do not place any restrictions on transmitter operation. An
example is a requirement to operate at reduced power.
Ensure that the antenna is switched to the proper pattern, if used.
Check the status indicators. If there are any OVERLOAD or
FAULT indications, record them in the transmitter maintenance
log, then operate the “RESET” button. This should clear the
overload indication. If any indications do not clear and are still
present after operating the RESET, refer to paragraph “Fault
status indications will not clear when reset.” If all overload
indications are cleared when the RESET is operated, continue
with transmitter turn on procedure, below. (Note that the red
REMOTE status indicator is not a fault indication, and indicates
that the transmitter may be operated by remote control equipment.)
cal Control)
The following paragraphs describe checks to be made before
normal daily turn-on if the transmitter is to be operated using the
controls on the transmitter.
3.5 Transmitter Turn-On Procedure
Check the transmitter maintenance log to make sure that maintenance performed on the transmitter, or other abnormal conditions, do not place any restrictions on transmitter operation. An
example is a requirement to operate at reduced power.
Set the selector switch below the POWER meter on the meter
panel to FORWARD, if it is not already in that position.
Ensure that the transmitter rf output is properly terminated into
the antenna. This may include determining that antenna pattern
switching is correct.
Check the Remote Control (LOCAL/REMOTE) switch to ensure that it is in the correct position (LOCAL, if the transmitter
is to be operated only from its front panel controls).
03/16/2009
When the Preoperational Checkout has been completed and no
problems are present, the transmitter is ready to turn on.
Depress the LOW, the MEDIUM, or the HIGH push-button on
the meter panel, depending on power level desired. Each of these
three push buttons will turn the transmitter on at the power level
which has been preset.
The push-button you have operated should illuminate, and power
will come up to the preset level. (If you are at the transmitter,
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-1
you should also hear three “clicks” as contactors operate, then
the blower should start, then power will come up.) If FORWARD POWER is not correct, verify that you have selected the
correct power level (LOW, MEDIUM or HIGH). If not, depress
the proper power level button, and check forward power again.
NOTE
IF AC PRIMARY POWER HAS BEEN OFF FOR SOME TIME,
AND THE TRANSMITTER DOES NOT COME ON, REFER TO
PARAGRAPH UNDER “EMERGENCY OPERATION.”
If the correct power level has been selected, but an adjustment
in power is still needed, press the RAISE button to INCREASE
power, or the LOWER button to DECREASE power. When you
hold the button depressed and watch the FORWARD POWER
indication, the power will change slowly. Hold the button until
the power is correct.
NOTE
RAISE and LOWER buttons will only change power level if the
transmitter is operating in the HIGH, MEDIUM, or LOW function. This new power level will become the preset power until it
is changed again.
Check transmitter panel meter readings for normal values. If
abnormal meter readings are obtained, refer to the Troubleshooting Section VI of the manual.
3.6 Transmitter Turn-OFF Procedure
To turn off (de-energize) the transmitter, depress the OFF pushbutton. The HIGH, MEDIUM, or LOW lamp will go out, you
should hear the contactor as it de-energizes, and the blower will
stop. With the POWER switch in the FORWARD position, the
Power meter should indicate zero power. Supply voltage and
supply current meters should both indicate zero readings.
NOTE
The +8 volt, -8 volt, +22 volt and -22 volt positions on the front
panel multimeter will still indicate normal voltages after the OFF
button has been operated. If these voltages are metered on a remote control system, they will also indicate. This is because the
transmitter low voltage supplies remain on as long as primary ac
power is still applied to the transmitter.
problems, but in reality are normal transmitter actions for certain
possible fault conditions. Also included are a list of basic faults
that could occur and references to other portions of the manual
for assistance in clearing these faults. The Troubleshooting
section of the manual contains more detailed information on fault
troubleshooting.
It is very important that operators log all abnormal operation,
such as incorrect meter readings, overloads, fault indications,
and transmitter shut-downs. A log or record of abnormal operating conditions will be useful to technical personnel in locating
and correcting transmitter or other system problems.
3.7.1 AC Power Failure (When not using Controller
Backup Battery)
No operator action is required for ac power failures of less than
about 45 minutes. The transmitter will automatically return to an
on-air condition, at the same power level as before the power
failure.
If ac power is off for more than about 45 minutes, the transmitter
may not automatically return to its on-air condition. Normal
operator turn-on procedures will be required. Power output may
be zero, but supply voltage will be present. If so, power will need
to be set using the RAISE push-button.
It is also possible that the transmitter may not come on immediately when the LOW, MEDIUM or HIGH button is depressed.
If the power has been off for a period of time, approximately one
minute may be required after primary power returns before
internal turn-on circuits are operational. Simply wait about one
minute and try depressing the LOW, MEDIUM or HIGH button
again.
3.7.2 AC Power Failure (When Controller Backup
Battery is used)
When a backup battery is installed in the transmitter controller,
the transmitter will automatically return to an on-air condition
after an AC power failure, at the same power level as before the
power failure, unless the backup battery has failed. A backup
battery should last for at least 6 months before requiring replacement. If the transmitter does not come back on, refer to the
following section, “Transmitter Will Not Come ON.”
WARNING
AC POWER IS STILL APPLIED TO THE TRANSMITTER CABINET
WHEN ONLY THE OFF SWITCH IS DEPRESSED. ENSURE ALL
VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND
GROUNDING STICK IS USED TO GROUND ALL POINTS WHERE
AC OR RF POWER HAS BEEN APPLIED BEFORE SERVICING
THE TRANSMITTER.
3.7 Emergency Operating Procedures
The following information is provided only as a guide to follow,
for some emergency circumstances that may occur, and in no
way includes all the emergencies that may occur. This is only
intended to make the operator aware of some basic operational
characteristics of the transmitter which may indicate serious
3-2
3.7.3 Transmitter Will Not Come ON
If the transmitter does not come on when the LOW, MEDIUM
or HIGH button is depressed, or the LOW, MEDIUM or HIGH
remote control command is given, and no RED fault status
indications or remote fault status indications are present, try the
following:
a. If it is not known whether the high voltage has turned on,
check the SUPPLY VOLTS position on the front panel
multimeter or the SUPPLY VOLTS remote reading. If
supply voltage is present, try increasing power with the
RAISE push-button or remote control input. If the transmitter can be brought up to normal power, and meter
readings are normal, normal operation may continue.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
b. If supply voltage is not present, and the transmitter has
been off for a period of time, try waiting for approximately
one minute. If the transmitter now comes on normally,
continue normal operation. Log or record this condition so
that technical personnel can check for possible problems.
c. If supply voltage does not come on after waiting for
approximately one minute, there is probably a transmitter
fault. See the Troubleshooting section of the Manual.
3.7.4 Transmitter Shuts OFF
The operator should first check for overload or fault indications,
including status indicators (LED’s) that are red or remote fault
indications, and log any fault indications that are found.
Press the RESET button on the status indicator panel to clear
fault indications, or press the remote control reset. LED’s should
all change from red to green, and remote fault indications should
clear. If any LED’s are still red or any remote fault indications
are still present, refer to the next section, “Fault status indications
will not clear when reset.”
When the fault indicators clear (are all green), follow normal
turn-on procedure, by depressing the HIGH, MEDIUM, or LOW
button then checking FORWARD POWER, and other meter
readings.
If the transmitter shuts off again, and the same overload or fault
indication comes on, try turning the transmitter on by using the
LOW power button. (Under some conditions, a transmitter may
operate satisfactorily at reduced power.) If it will not come on at
LOW power, see the Troubleshooting section of the manual.
3.7.5 Fault status indications will not clear when re-
set, or Fault Indications Continue to Occur
If any RED status indications are still present after a depressing
the “RESET” push-button switch on the transmitter front panel,
or any remote FAULT indications are still present after a RESET
command, the type of fault indication determines what should
be done next. The following paragraphs give procedures to
follow for each type of fault.
3.7.6 Remote Status LED is Red
This is not a fault indication. When the REMOTE status LED is
illuminated, the transmitter may be operated either by remote
control or from the front panel controls.
3.7.7 Oscillator, Buffer Amp or Driver Fault
Fault Indicator is Red or any of the following REMOTE fault
indications are present:
a. Oscillator A17 RF not Present
b. Buffer Amp A16 RF not Present
c. Predriver RF not Present
Do not attempt to operate the transmitter. See the Troubleshooting section of the manual or the Troubleshooting section of the
particular module at fault.
03/16/2009
3.7.8 RF Amp “Envelope OK” Fault (Remote “En-
velope Error” Fault)
Fault indicator is Red or flashing Red, or a remote RF Amp
Envelope Error fault indication is present. The transmitter will
continue to operate safely, although distortion will be increased.
The Envelope Error fault indication can not be RESET. The fault
must be corrected to clear the fault indication. Continue normal
operation, and see the Troubleshooting section of the manual for
more information.
3.7.9 Audio Input +15V or -15V Fault. A/D Con-
verter +15V, -15V, +5V Fault
Momentarily push the “Reset” button. If the fault indicator still
remains Red, and will not Reset then that regulator circuit is at
fault. Check the Troubleshooting section of the manual and the
troubleshooting section for that individual board. The fault must
be located and repaired before the fault indication can be cleared.
3.7.10 A/D Converter Conversion Error Fault
In this fault condition the transmitter will be on as indicated by
the LOW, MEDIUM, or HIGH indicator but No power output
will be indicated on the transmitter meter. This fault indication
cannot be reset. The OFF button should be depressed and the
transmitter serviced using the Troubleshooting section of the
manual.
3.7.11 Modulation Encoder Cable Interlock Fault
Momentarily push the “Reset” button. If the fault indicator still
remains Red, a Cable Interlock problem is indicated. Do not
attempt to operate the transmitter. The fault must be located and
repaired before the fault indication can be cleared.
3.7.12 DC Regulator +5V or B- Fault
Momentarily push the “Reset” button. If the fault indicator still
remains Red, and will not Reset then that regulator circuit is at
fault. Check the Troubleshooting section of the manual and the
troubleshooting section for that individual board. The fault must
be located and repaired before the fault indication can be cleared.
3.7.13 Output Monitor +5V or -5V Fault
Momentarily push the “Reset” button. If the fault indicator still
remains Red, and will not Reset then that regulator circuit is at
fault. Check the Troubleshooting section of the manual and the
troubleshooting section for that individual board. The fault must
be located and repaired before the fault indication can be cleared.
3.7.14 Output Monitor VSWR Fault
Refer to the section on VSWR FAULTS below.
3.7.15 Interlocks: External, Air or Door Interlock
Fault
Remote fault indications are:
a. External Interlock Open
b. Air Interlock Open
c. Door Interlock Open
If the AIR interlock indicator is illuminated Red, depress the
“Reset” button. Again turn on the transmitter by depressing the
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-3
LOW, MEDIUM, or HIGH push-button. If the transmitter turns
on then immediately shuts off and the AIR interlock indicator is
illuminated, Do Not attempt to operate the transmitter further.
See the Troubleshooting section of the manual. If the External
Interlock or Door Interlock indicators are illuminated, The fault
indication cannot be cleared until the problem is corrected. If a
Door Interlock is indicated, ensure that both interlocked doors
are closed properly. If the External Interlock fault is illuminated,
check all equipment (such as a phasor) which are connected to
this interlock for a fault condition.
3.7.16 Overloads
There are five Overload Fault indications:
a. Supply Over Voltage Fault (Supply Voltage Overload)
b. Supply Over Current Fault (Supply Current Overload)
c. Supply Fault (High Voltage Supply Failure)
d. RF Under Drive (Under-Drive Overload)
e. RF Over Drive (Over-Drive Overload)
For overload faults, see the Troubleshooting section of the
manual. Generally, the fault indication cannot be reset or cleared
until the problem is corrected. The following is a list of the
Overloads and the appropriate transmitter action taken when an
overload is encountered. Some basic operations can be attempted
to keep the transmitter on the air if the fault is not due to a specific
transmitter part failure.
3.7.17 VSWR Sensor “Status” Indicator is Red (Re-
mote VSWR Self Test Pass/Fail Fault)
Notify qualified maintenance personnel. The manufacturer recommends that the transmitter be turned off until the VSWR
protection circuits can be repaired, to avoid the risk of damage
to power amplifier circuits or stages.
A Red VSWR Sensor “Status” indicator LED, or a remote
VSWR Self Test Pass/Fail Fault indication may occur after an
AC Power failure, or when the Manual Test push-button is
pressed, or a remote Manual VSWR Self Test command is given.
This fault indication occurs when the VSWR fault sensor circuits
are not operating. A VSWR fault under these conditions could
result in failure of RF power amplifier circuits or transistors, as
transmitter VSWR protection circuits have failed. It is recommended that the transmitter be shut off until the VSWR protection circuits can be repaired.
3.7.18 Type 3 Fault Indication (Remote Indication
3.7.16.1 Supply Over Current
Supply Over Current faults may be due to over modulation, and
emergency operation may continue temporarily at reduced
power. During a Supply Over Current fault condition the transmitter may shut off for about two and one half seconds and the
indicator may change to amber for this amount of time. At this
time the transmitter will attempt to restart by itself and if it
succeeds, the indicator will change back to green. If the transmitter faults again when it automatically restarts, it will no longer
restart and the indicator will now remain RED. Corrective action
or emergency operating procedures for these indicator conditions follow:
a. Transmitter shuts off and then automatically restarts. Supply Overcurrent Fault indicator flashes on Amber for about
two and a half seconds when the transmitter is off then
returns to Green: Check modulation level. If over modulating on positive peaks, reduce audio level to reduce
modulation. If modulation level is normal, but fault indicator continues to flash on and off, try reducing audio
level.
b. Transmitter shuts off and then automatically restarts. Supply Overcurrent Fault indicator flashes on Amber for about
two and a half seconds when the transmitter is off then
returns to Green: Try operating at LOW power, on a
temporary, emergency basis, and see the troubleshooting
section of the manual.
c. Transmitter shuts off and no longer automatically restarts.
The Supply Overcurrent Fault indicator stays on Red and
the transmitter is shut off: Log or record the fault, RESET
3-4
the fault indicators, and try turning the transmitter on. If
the fault occurs again, try operating at LOW power. If the
transmitter will operate at LOW power, operation may
continue on a temporary, emergency basis.
d. Supply Overcurrent Fault indicator comes on and transmitter will not operate even at LOW power and with
reduced audio level: see the Troubleshooting section of the
manual.
Only)
Normally, with a remote Type 3 Fault indication, the transmitter
continues to operate, but at reduced power. This is most likely
due to a VSWR fault. See the “VSWR Faults” below.
3.7.19 Bandpass Filter VSWR Fault (Remote: “In-
ternal VSWR Fault”)
Refer to “VSWR Faults,” below.
3.7.20 Antenna VSWR Fault (Remote: “External
VSWR Fault”)
Refer to “VSWR Faults,” below.
3.7.21 VSWR Faults
VSWR Fault indication flashes on and off:
a. This may be a normal occurrence during a thunderstorm,
rain storm, or under conditions of blowing snow or sand,
and will stop when the weather conditions stop.
b. The VSWR indicator may flash on and off when over
modulation occurs. Reducing modulation to normal levels
may correct the condition.
c. If the VSWR indicator flashes on and off and weather
conditions or over modulation are not the cause, transmitter and/or antenna problems are indicated. Operation at
reduced power may also stop the VSWR faults until the
problem can be identified by referring to the Troubleshooting section of the manual.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
3.7.21.1 VSWR Fault Indication stays ON
A VSWR indicator LED that stays RED until reset, indicates a
longer term VSWR condition existed, and the transmitter may
have lowered the power output to respond to this condition. The
power output can be again increased if this was only a temporary
condition. If the Indicator will not reset or the power level of the
transmitter has been lowered drastically, this indicates more
serious VSWR problems and the Troubleshooting section of the
manual should be referred to.
Many VSWR overloads are cause by arcing in the antenna
system, and can be “cleared” by removing the transmitter rf
output for a short period of time. In other instances, the transmitter can be operated safely at reduced power. The DX-10 contains
circuitry to take both types of corrective action automatically.
A VSWR overload will cause the power output of the DX-10 to
go to zero for about 15 milliseconds. This is enough time to allow
an arc to extinguish, but may not even be noticeable to a listener.
The VSWR indicator light will come on for about one half
second, then will go out again. If there are several repeated
VSWR overloads in a short period of time, the transmitter will
automatically reduce its power output and the VSWR status
indicator will stay red.
3.8 Tuning and Loading Control Adjust-
ment
This section of the DX-10 Maintenance Manual contains information on tuning the transmitter, which includes adjusting the
Tuning and Loading controls. Other tuning adjustments, including Buffer and Driver tuning, should not be required on a routine
basis, and information is included in the Maintenance section of
this Technical Manual.
This paragraph contains a brief description of the Tuning and
Loading controls in the DX-10 transmitter. The TUNING and
LOADING controls in the DX-10 operate differently than similar controls on most transmitters. The DX-10 output network is
factory tuned to match the Power Amplifier output impedance
to 50 ohms. The directional couplers for forward and reflected
power measurement and the phase detector for VSWR protection are all located at this 50 ohm point. If all Broadcast transmitters always had exactly a 50 ohm resistive load, no further
impedance matching would be required. Antenna loads found at
stations, however, are often not quite 50 ohms. Therefore, the
DX-10 has incorporated an additional impedance matching network (a TEE network), and the Tuning and Loading controls are
adjustments to this network. This allows operating the transmitter into an antenna system that has an impedance close to, but
not exactly, 50 ohms. (The network is specified to operate with
a VSWR of up to 1.3:1 at the transmitter output terminal.)
A step by step adjustment procedure for the DX-10 Tuning and
Loading controls follows:
a. Switch the Forward-Reflected power meter selector
switch to the REFLECTED power position and switch the
03/16/2009
front panel multimeter to the PHASE DETECTOR NULL
(ANTENNA) position.
b. Depress the LOW power button, to turn the transmitter on
at low power. (If the controls are far out of adjustment, or
the load impedance is much different from 50 ohms, the
VSWR status indicator may turn red, and the transmitter
power output will decrease. This is normal operation of the
transmitter protection circuitry, and the tuning procedure
may be continued with the next step.)
c. Adjust both TUNING and LOADING controls for minimum reflected power (it should be possible to reduce
reflected power to zero). These controls will interact, and
it will be necessary to adjust first one, then the other, until
a minimum reflected power reading is obtained. The tuning and loading controls should be near the center of their
range when this step is completed. If minimum reflected
power cannot be obtained within the range of the controls,
the load impedance is probably not close to 50 ohms, and
should be measured with an RF bridge.
NOTE
Do not use the tune and load controls to adjust for any meter
indications except for a null (minimum) in REFLECTED POWER
and Phase Detector Null (ANTENNA). It should be noted that the
Phase Detector Null (ANTENNA) indication will provide a finer
resolution of the null (minimum) when adjusting the Loading and
Tuning controls.
d. A fine adjustment can be made by making small adjustments to the TUNING and LOADING controls for a
minimum reading on the Phase Detector Null (ANTENNA) position of the front panel multimeter.
e. Increase transmitter output power to normal with the
LOW, MEDIUM, HIGH, RAISE and LOWER controls,
as required. If the Tuning and Loading controls have been
properly adjusted, the reflected power reading should remain low. If the VSWR status indicator indicates red,
voltage breakdown may be occurring somewhere in the
antenna system, or in the tuning or switching systems
between the antenna and the transmitter, or in the transmission line, when the higher power is applied.
f. If the REFLECTED POWER and Phase Detector Null
(ANTENNA) readings increase when output power is
increased, repeat adjustment of the TUNING and LOADING controls for minimum readings.
g. Minimum readings on REFLECTED POWER and Phase
Detector Null (ANTENNA) meters should approximately
occur with the same adjustment of the Tuning and Loading
controls. If the controls must be adjusted differently for
nulls in these readings, either the directional coupler or the
phase detector may be adjusted improperly. Impedance
measuring equipment will be required to adjust these
circuits. Refer to the Maintenance section of this manual
for adjustment procedures if required. Note that the Reflected Power null may not exactly coincide with Phase
Detector Null (ANTENNA). The Phase Detector Null
(ANTENNA) should be the indication used for final tuning touch-up.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-5
Table 3-1
DX-10 Transmitter, Controls and Indicators
REF.
CONTROL/INDICATOR
1
Loading Control
“Tee Matcher” control for matching load to 50 ohm transmitter impedance.
2
Tuning Control
“Tee Matcher” control for matching load to 50 ohm transmitter impedance.
3
Switch Board/Meter Panel
See Table 3-2 and Figure 3-2.
4
Status Panel
See Table 3-3 and Figure 3-3.
3-6
FUNCTION
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
1
2
3
4
Figure 3-1
DX-10 Front View, Controls and Indicators
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-7
Table 3-2
Switch Board/Meter Panel, Controls and Indicators
REF.
CONTROL/INDICATOR
1
VOLTAGE multimeter
Indicates voltages at points selected by the Multimeter Switch (Ref.
11).
2
SUPPLY CURRENT meter
Indicates total high voltage supply current being supplied to the
Power Amplifier and RF Driver module.
3
POWER meter
Indicates either FORWARD or REFLECTED power at the transmitter output, whichever is selected by the POWER METER selector
switch (Ref. 4).
4
POWER, selector
Selects Forward power output or Reflected power, to be read on the
POWER meter.
5
OFF, push-button
Used to turn the transmitter off. (Low voltage supplies remain on as
long as AC primary power is applied).
6
LOWER, push-button
and Indicator
Used to adjust power level. When the transmitter is in the LOW, MEDIUM, or HIGH power mode, depress to LOWER power output and
hold until desired power is reached. INDICATOR illuminates while
power is being lowered.
7
RAISE, push-button
and Indicator
Used to adjust power level. When the transmitter is in the LOW, MEDIUM, or HIGH power mode, depress to RAISE power output and
hold until desired power is reached. INDICATOR illuminates while
power is being raised.
8
HIGH, push-button
and Indicator
Used to turn the transmitter on at the preset HIGH power level, or to
change power to the preset HIGH power level. INDICATOR: The
push-button will illuminate when in the HIGH power mode.
9
MEDIUM, push-button
and Indicator
Used to turn the transmitter on at the preset MEDIUM power level, or
to change power to the preset MEDIUM power level. INDICATOR:
The push-button will illuminate when in the MEDIUM power mode.
10
LOW, push-button
and Indicator
Used to turn the transmitter on at the preset LOW power level, or to
change power to the preset LOW power level. The push-button will illuminate when in the LOW power mode.
11
MULTIMETER switch
Selects the desired point to be monitored by the VOLTAGE multimeter. An LED will illuminate to indicate which function has been selected.
3-8
FUNCTION
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 3-2
Switch Board/Meter Panel, Controls and Indicators
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-9
Table 3-3
Status Panel, Controls and Indicators
REF
CONTROL/INDICATOR
FUNCTION
1
LOCAL/REMOTE, switch
Selects LOCAL or REMOTE control of the transmitter. (Remote
monitoring is operational in either the LOCAL or REMOTE switch
position.)
2
LOCAL, status indicator
Red LED indicates that the remote control inputs to the transmitter
are disabled, and only local control is possible.
3
REMOTE, status indicator
Green LED indicates that the transmitter remote control inputs are active. (The transmitter may still be controlled with the panel push buttons as well.)
4
AUDIO INPUT board, -15V supply
status indicator
Bicolor LED indicator. Indicates status of -15 volt supply on the
audio input board. GREEN indicates normal operation; RED indicates -15 volt supply fault.
5
AUDIO INPUT board,+15 V supply
status indicator
Bicolor LED indicator. Indicates status of +15 volt supply on the
audio input board. GREEN indicates normal operation; RED indicates +15 volt supply fault.
6
OSCILLATOR, rf output status
indicator
Bicolor LED indicator. Indicates oscillator board rf output status.
GREEN indicates normal rf output; RED indicates low or no rf output.
7
BUFFER AMP,
rf output status indicator
Bicolor LED indicator. Indicates buffer amplifier rf output status.
GREEN indicates normal rf output; RED indicates low or no rf output.
8
PREDRIVER, rf output
status indicator
Bicolor LED indicator. Indicates predriver rf output status. GREEN
indicates normal rf output; RED indicates low or no rf output.
9
RF AMP, ENVELOPE OK
indicator
Bicolor LED indicator. GREEN indicates that the modulated wave
form envelope is the same as the audio input signal; RED indicates
that the modulated wave form envelope is distorted, normally because
of over modulation or a Big Step rf amplifier failure. Significant
changes in antenna impedance can also cause this indicator to flash or
light red.
10
OUTPUT MONITOR,
BANDPASS FILTER
VSWR indicator
Bicolor LED indicator. GREEN indicates that there is low reflected
power at the input of the bandpass filter; RED indicates that reflected
power at the filter input is above the level set by the VSWR trip adjust control.
11
OUTPUT MONITOR,
+5 V supply status indicator
Bicolor LED indicator. Indicates status of +5 volt supply on the Output status Monitor board. GREEN indicates +5 volts present; RED indicates +5 volt supply fault.
12
OUTPUT MONITOR,
-5V supply status indicator
Bicolor LED indicator. Indicates status of -5 volt supply on the Output status Monitor board. GREEN indicates -5 volts present; RED indicates -5 volt supply fault.
13
OUTPUT MONITOR,
ANT. VSWR, status indicator
Bicolor LED indicator. Indicates VSWR status. RED indicates that
VSWR at the transmitter’s 50 ohm monitor point is above the threshold set by “VSWR Trip Adjust” control, caused by Tee Matcher mistuning or antenna system fault (the threshold is 500 W PEP reflected
power). GREEN indicates low VSWR.
14
VSWR SENSOR,
“STATUS” indicator
(VSWR Self-Test result)
Bicolor LED indicator. Indicates result of “VSWR Self-Test.” RED
indicates VSWR logic fault, GREEN indicates VSWR protection
logic is functioning normally. (“VSWR self-test” can be initiated
manually with “VSWR SENSOR, Manual Test,” and is performed
automatically whenever ac power is restored).
3-10
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Table 3-3. Continued
Status Panel, Controls and Indicators
REF
CONTROL/INDICATOR
FUNCTION
15
VSWR SENSOR,
MANUAL TEST,
push-button
Used to test operation of VSWR logic, result of test is displayed on VSWR SENSOR, STATUS indicator (Ref. 14, above).
When the push-button is depressed, both
the Bandpass Filter and Antenna VSWR
status indicators will momentarily go red,
then Sensor Status Indicator will indicate
green if VSWR logic is functioning properly.
16
RF OVER DRIVE,
status indicator
RED indicates excessive rf drive level to
the Power Amplifier. GREEN indicates
drive level is below the Overdrive threshold.
17
RF UNDER DRIVE,
status indicator
RED indicates low rf drive level to the
Power Amplifier. GREEN indicates drive
level above the preset threshold.
18
SUPPLY FAULT,
overload indicator
RED indicates that the Power Supply Protection circuit has detected a High Voltage
Power Supply fault (an imbalance in three
phase voltages from transformer T1,
caused by loss of one phase or phase imbalance on incoming primary power, transformer T2 faults, rectifier failure, or
contact failure on K2. GREEN indicates
no fault.
19
OVER CURRENT,
O.L. status indicator
GREEN status indicates normal status;
RED indicates that either average or peak
supply current has exceeded preset levels.
20
OVER VOLTAGE,
O.L. status indicator
Bicolor LED indicator. GREEN indicates
normal status; RED indicates main power
supply voltage has exceeded 260 volts DC.
21
OVERLOADS, RESET
push-button
Resets the overload indicators; when depressed, overload indicators will change
from RED to GREEN if the cause of the
overload has been cleared. Depressing the
RESET button will also reset any other
front panel fault indicator.
22
DOOR INTERLOCKS,
status indicator
Bicolor LED indicator. GREEN indicates
both doors doors closed; RED indicates
that a door is open, or not fully closed.
23
AIR INTERLOCKS,
status indicator
Bicolor LED indicator. Indicates proper
air pressure in the PA combiner/motherboard compartment. GREEN indicates sufficient air pressure (air flow from the
blower), RED indicates “air flow fault.”
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-11
Table 3-3. Continued
Status Panel, Controls and Indicators
24
EXT. INTERLOCKS,
status indicator
Bicolor LED indicator. Indicates status of external interlocks.
GREEN indicates a completed circuit; RED indicates an open circuit.
25
MODULATION ENCODER,
CABLE INTERLOCK,
status indicator
Bicolor LED indicator. Indicates status of cables between the MODULATION ENCODER board and the Combiner/Motherboards. It also
indicates when any PA RF Amplifier module is not properly inserted
into the motherboard. GREEN indicates all cables and modules are
properly installed; RED indicates that a cable or module is not installed or connected.
26
DC REGULATOR,
+5 V supply
status indicator
Bicolor LED indicator. Indicates status of +5 volt supply on the DC
Regulator board. GREEN indicates normal operation; RED indicates
+5 volt supply fault.
27
DC REGULATOR,
B- supply
status indicator
Bicolor LED indicator. Indicates status of B- supply on the DC Regulator board. GREEN indicates normal operation; RED indicates Bsupply fault.
28
A/D CONVERTER,
+15 V supply
status indicator
Bicolor LED indicator. Indicates status of +15 volt supply on the A/D
Converter board. GREEN indicates normal operation; RED indicates
+15 volt supply fault.
29
A/D CONVERTER,
-15 V supply
status indicator
Bicolor LED indicator. Indicates status of -15 volt supply on the A/D
Converter board. GREEN indicates normal operation; RED indicates 15 volt supply fault.
REF
CONTROL/INDICATOR
FUNCTION
30
A/D CONVERTER,
CONVERSION ERROR,
status indicator
Bicolor LED indicator. GREEN indicates normal operation of analog
to digital (A/D) converter. RED indicates conversion error in A/D
converter.
31
A/D CONVERTER,
+5V supply
status indicator
Bicolor LED indicator. Indicates status of +5 volt supply on the A/D
Converter board. GREEN indicates normal operation; RED indicates
+5 volt supply fault.
3-12
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
9
7
8
10
11
13
12
6
14
5
4
15
3
2
1
28
30
26
31
27
29
23
22
21
25
20
19 18
24
16
17
Figure 3-3
Status Panel, Controls and Indicators
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-13
Table 3-4
DX-10 Controls and Indicators, Inside Non-interlocked Compartment and Interlocked Power Supply Compartment
REF
CONTROL/INDICATOR
FUNCTION
1
Predriver A, B,
Fuse Indicators,
A16DS1, DS2.
Indicates open Predriver supply line fuses, for Predriver Section A
and Section B. (Fuses and indicator LEDs are located on Buffer Amplifier A16A).
2
Buffer Amplifier
Fuse Indicator,
A16DS3.
Indicates open Buffer Amplifier Fuse, on Buffer Amplifier board A16.
3
Predriver Fuse
indicators,
A40DS1, DS2.
Indicates open fuses on Predriver
4
L1 Adjustment
(hidden from view).
Adjusts predriver output tuning inductor.
5
L2 Adjustment
(hidden from view.)
Adjusts rf driver output, tuning inductor.
6
R1, RF Driver Drive
Level adjustment
Adjusts supply voltage to predriver, thereby adjusting input drive
level to the rf driver stages.
7
RF Driver Fuse
Indicators, (DS1
and DS2).
Indicates open fuses on RF Driver modules (two indicators for each
of three modules, A41, A42 and A43).
8
Power Amplifier
Module, Open Fuse
Indicators (DS1 and
DS2 on each module).
Indicates open fuses on PA modules. There are two indicators on each
of the 48 PA modules (A44 through A91).
9
Location of Fuse
Board A14.
Refer to Table 3-7 and Figure 3-7, for fuse locations on Fuse Board
A14.
10
Blower Motor Fuses,
F7, F8, & F9
Fuses for three phase ac power to blower motor B1.
11
Low Voltage Supply,
MOV Fuses and Interlock Fuse
F1, F2, F3 & F6
Fuses are INSIDE PROTECTIVE COVER. Fuses and MOV’s are in
the AC power leads to protect the Low Voltage Supply.
12
Low Voltage Supply
Power Switch, S11.
Rocker Switch, turns off primary power for Low Voltage Power Supply.
13
Low Voltage Power
Supply Circuit Breakers,
CB1, CB2
Circuit Breakers for Low Voltage Power Supply. Circuit breakers
“pop out” when they open; push in to reset.
3-14
.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
3
4
6
7
5
8
2
1
9
10
11
12
13
Figure 3-4
DX-10 Controls and Indicators, Inside Non-interlocked Compartment and Interlocked Power Supply Compartment
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-15
Table 3-5
DX-10 Controls and Indicators, Left Side of Non-interlocked Compartment and on inside of Front Door
REF.
CONTROL/INDICATOR
1
Modulation Encoder
Indicator LED’s:
DS1, Intlk Off, Red;
DS2, Intlk On, Green;
DS3, PA Off, Red;
DS4, PA On, Green
LED’s on Modulation Encoder board A36, indicate Cable Interlock
status and “PA Off” logic output status.
2
PA ON/OFF, Toggle
Switch A38S5
Switch, on Controller Board A38, turns PA “Off” when in Off position; allows PA to turn on under control of Modulation section when
in ON position.
3
“Supply Fault
Summary” Indicator,
A38DS1
RED LED, illuminates when any Controller Board power supply fault
occurs. Indicator located on Controller Board A38.
4
“Fast Power Set”
Push-button Switch,
A38S4
Depress and hold while “Raising” or “Lowering” power, for fast
power set. Switch is located on Controller Board A38.
5
“Conversion Error”
Indicator LED,
A34DS1
Illuminates RED when a Conversion Error is detected. Indicator is located on the front edge of the Analog to Digital Converter Board A34.
6
Audio Gain Adjust,
Potentiometer,
A35R15
Adjusts transmitter’s audio input sensitivity (audio level required for
100% modulation). Located on Analog Input board A35.
7
Audio Input
Impedance Selection
Select J1, J2, or J3 as required by source impedance of program equipment feeding the transmitter. (Located at top center on Analog Input
board A35).
8
“ANT TRIP” Push-button
Switch, A27S1
Depress to manually test Antenna VSWR logic. Switch is located on
Output Monitor Board A27.
9
“Press and Hold to Null Each Phase
THIS IS A MAINTENANCE ADJUSTMENT ONLY. Depressing S3
Detector,” Push-button Switch A27S3. Disables VSWR Detection while nulling phase detectors. Refer to
Section 5, Maintenance, for more information and adjustment procedures.
10
“BPF TRIP” Push-button Switch,
A27S5
Depress to manually test Bandpass Filter VSWR logic. Switch is located on Output Monitor Board A27.
11
MEDIUM Power Mod Monitor Sample Adjust, A27R31
Adjusts modulation monitor sample level when the transmitter is at
Medium power (adjust L107 for Low Power Sample before adjusting
this control).
12
HIGH Power Mod Monitor Sample
Adjust, A27R33
Adjusts modulation monitor sample level when the transmitter is at
High power (adjust L107 for Low Power Sample before adjusting this
control).
3-16
FUNCTION
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
11
9
10
12
8
7
6
5
4
3
2
1
Figure 3-5
DX-10 Controls and Indicators, Left Side of Non-interlocked Compartment and on inside of Front Door
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-17
Table 3-6
DX-10 Controls and Indicators, Right side of Non-interlocked Compartment
REF.
CONTROL/INDICATOR
FUNCTION
NOTE
These potentiometer adjustments are accessible through holes in the compartment wall, and require a tuning tool with a guard
ring around the blade to keep the tool from slipping off the adjusting screw.
1
Access hole for Closed Loop Adjust,
Potentiometer, A22R12
Adjusts “Closed Loop” RF Drive level. Refer to Section 5, Maintenance, for information on adjustment.
2
Access hole for Open Loop/Closed
Loop slide switch A22S1
Selects “Open Loop” or “Closed Loop” operation of driver supply
regulator. “Open Loop” is used during tune-up, and possibly for temporary, emergency operation. Refer to Section 5, Maintenance, for information on adjustment.
3
Access hole for Open Loop Adjust Po- Adjusts “Open Loop” RF Drive Level. Refer to Section 5, Maintetentiometer, A22R2
nance, for information on adjustment.
4
RF Multimeter Selector Switch,
A23S1
Selects the parameter, or probe function, to be read on the RF Multimeter.
5
RF Multimeter, A23M1
Used to read rf driver parameters, and also to read dc and peak ac voltages using the probe next to the meter.
3-18
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
5
4
3
1
2
Figure 3-6
DX-10 Controls and Indicators, Right side of Non-interlocked Compartment
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
3-19
3-20
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section IV
System Operation
4.1 Introduction
This section of the maintenance manual will present the overall
principles of operation for the DX-10 AM TRANSMITTER,
including a review of Digital Modulation, and then will describe
circuits not included on circuit boards described in sections A
through R of this Technical Manual.
The first pages of Section 1 in this Technical Manual describe
the contents of Sections A through R, or you can refer to the
Table of Contents. This section is organized as follows:
a. Protection of Personnel.
b. Block Diagram Description.
c. Digital Modulation.
1. A short review of digital terms and concepts.
2. Quantized amplitude modulation.
3. Analog to digital conversion.
4. Digital to analog conversion.
5. DX-10 Power Amplifier section: basic principles.
6. Summary: DX-10 digital modulator.
d. Circuits not Described in Sections A Through R:
e. Power Supplies and Related Circuits:
1. AC Input Circuits: Description.
2. Low Voltage Power Supply Description.
3. High Voltage Power Supply Description.
4. Fuse Board (A24): Description.
5. Blower and Air Flow Sensing Unit.
6. Interlocks and Interlock Relays.
7. Metering.
f. RF Circuits:
1. RF driver combiner description.
2. RF Drive Splitter A15: Description.
3. Power Amplifier Section.
4. Output Combiner Description.
5. RF Samples in the Output Network.
6. Bandpass Filter (Output Network): Description.
7. Tee Matcher: Description.
8. Modulation Monitor Sample Coil.
4.2 Protection of Personnel
Interlock switches and power supply grounding have been provided on the DX-10 because of the low impedance, high current
capabilities of the high voltage power supply, which can provide
over 75 amperes continuous DC at +230 volts.
There are two safety switches for each of two interlocked doors.
An interlock switch turns the transmitter high voltage supply off
when either door is opened slightly, and when the door is opened
03/16/2009
a little further, a large mechanical shorting switch grounds the
high voltage supply output. Interlocked doors are the front door
for the power supply compartment (on the right side of the
transmitter, when you look at it from the front), and the access
door for the PA modules, at the back of the front center compartment.
Rear access panels are secured with quarter-turn fasteners, and
tools are required to remove them. Inside the transmitter, protective covers and plastic shields prevent accidental contact with
hazardous voltages, including AC primary power voltages.
Grounding sticks with insulated handles are located inside the
transmitter. Before touching any point which may have had
voltage applied during operation, make sure all AC power is
removed and use the grounding stick to ensure that no voltage
remains.
An External Interlock circuit is available at the external interface
to turn the transmitter off if access doors, panels or covers
protecting personnel from high power RF are removed. The user
must provide external interlock switches, as required for each
installation.
Most circuit boards in the transmitter operate only from low
voltages, and are located in a non-interlocked compartment.
You can enter this compartment without turning the transmitter
off by opening the center front door, which is held closed with a
magnetic catch. Within the non-interlocked compartment, no
voltages over 30 volts DC (to ground) or over 70 volts PEAK
AC are exposed. A plastic shield on the Output Monitor board
(A27) covers RF sample voltages which could exceed 70 volts
peak.
4.2.1 Discharging the High Voltage Supply
The Power Supply Discharge board discharges the high voltage
supply whenever the transmitter is turned off by the operator, by
a fault, or by an interlock.
When the transmitter is turned OFF or when the high voltage
supply contactors (K1 and K2) de-energize and turn off the
supply for any other reason (including faults or power failure),
contactor auxiliary contacts close and turn on two FETs which
discharges the high voltage power supplies through low-resistance power resistors. (High voltage supplies in the DX-10 are
+230 volt and +115 volt supplies, with high current capability).
Also, when either one of the interlocked access doors is opened,
a mechanical shorting switch directly grounds the high voltage
supply as well.
4.2.2 Location of Door Interlocks and Grounding
Switches
The front access door on the power supply compartment and the
RF Amplifier module access door at the rear of the front non-interlocked compartment are protected with interlock switches as
well as the mechanical high voltage grounding switches.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-1
4.2.2.1 Door Interlock Switches
4.2.2.3 Non-interlocked compartment
Each door interlock switch is operated by a small pin on the door,
which protrudes through a hole in the frame and holds a pushbutton switch closed. When the door is opened a small amount,
the pin no longer holds the switch closed and the switch contacts
open, opening the 24 volt AC coil voltage circuit for both high
voltage supply primary contactors (K1 and K2). K1 and K2 will
then open and turn on the Power Supply Discharge board, which
discharges the high voltage power supplies, as described above.
Also, a second contact on each interlock switch turns the transmitter off and activates an interlock status indicator.
The center front compartment of the transmitter is not interlocked. To gain access to the inside of this compartment, open
the center front door (the door with the Status Indicator Panel
and the Meter Panel). This door may be opened for access to the
circuit boards inside without turning the transmitter off. Maximum voltages inside this non-interlocked compartment are unregulated +22 VDC and -22 VDC, and 70 volts PEAK (AC +
DC). (The non-interlocked compartment is also sometimes
called the “Cold compartment,” because there are no high voltages inside.) Turning off the transmitter or opening interlocked
doors does NOT turn off low voltage supplies, and low voltages
are still present in this compartment. A separate low-voltage
supply rocker switch, S11, is located at the bottom of the right
hand side of the non-interlocked compartment to turn off low
voltage supplies.
4.2.2.2 Grounding Switches
When the door is opened further, a mechanically operated shorting switch with heavy contacts closes, shorting the power supply
to the cabinet ground and eliminating any possible voltage still
remaining on the filter capacitors.
WARNING
TO DE-ENERGIZE THIS TRANSMITTER, TURN THE TRANSMITTER OFF AS YOU NORMALLY WOULD BY DEPRESSING THE
OFF BUTTON. THIS WILL DE-ENERGIZE THE HIGH VOLTAGE
SUPPLY. IF YOU MUST ENTER THE TRANSMITTER, SET THE
REMOTE/LOCAL SWITCH ON THE STATUS INDICATOR PANEL
TO “LOCAL.” TURN OFF THE WALL DISCONNECT SWITCH TO
REMOVE ALL PRIMARY POWER. CHECK THE SUPPLY VOLTAGE METER TO BE SURE THE HIGH VOLTAGE SUPPLY IS
DISCHARGED. WHEN AN INTERLOCKED DOOR IS OPENED, A
MECHANICAL SHORTING SWITCH SHORTS THE HIGH VOLTAGE SUPPLY TO GROUND. GROUNDING STICKS ARE PROVIDED IN THE TRANSMITTER AND SHOULD BE USED TO ASSURE THAT ALL VOLTAGE HAS BEEN REMOVED.
Always be sure the voltage is discharged before you open an
interlocked door, otherwise, substantial damage may be done to
circuit card foil, grounding devices, and the power supply filter
capacitors. Each large power supply filter capacitor has a resistor
directly across its terminals to provide slow discharge in the
unlikely event other discharge mechanisms fail. Also, there are
additional filter capacitors located on the Power Amplifier combiner/motherboards, close to the modules. Each of these capacitors also has a safety bleeder resistor directly across its terminals.
In the power supply compartment, there are some terminals
which have primary AC voltage on them whenever primary
power is applied (whenever the wall switch is ON), even if the
transmitter is turned OFF. These terminals are all protected by
covers and protective plastic shields.
WARNING
PROTECTIVE COVERS INSIDE THE TRANSMITTER SHOULD
NOT BE REMOVED UNLESS ABSOLUTELY NECESSARY. REMOVE ALL PRIMARY POWER BEFORE REMOVING ANY PROTECTIVE COVERS. IF PROTECTIVE COVERS ARE REMOVED,
REPLACE ALL PROTECTIVE COVERS. ENSURE THAT ALL
COVERS ARE IN PLACE BEFORE CLOSING THE TRANSMITTER
DOOR AGAIN.
CAUTION
DO NOT GROUND ANY CIRCUITS OR POINTS WITHIN THE NONINTERLOCKED COMPARTMENT WHEN AC PRIMARY POWER IS
APPLIED TO THE TRANSMITTER. USE CAUTION WHEN CONNECTING ANY TEST LEADS, ESPECIALLY WHEN CONNECTING
TEST EQUIPMENT GROUND LEADS. ACCIDENTALLY GROUNDING VOLTAGES CAN DAMAGE COMPONENTS OR PRINTED CIRCUIT BOARD FOIL.
Some circuit grounds and grounding points in the DX-10 are
carefully controlled, to eliminate ground loops and noise pickup.
Connecting test equipment grounds on some circuit boards may
cause ground loops that result in unwanted noise, reduced equipment performance, or changes in wave forms or voltages. The
Analog to Digital Converter board, A34, is particularly sensitive
to improper grounds. Test equipment ground leads should be
connected to the proper test point on the printed circuit board
when making measurements.
4.3 Block Diagram Description
The following brief block diagram description refers to Figure
4-1, DX-10 Block Diagram. This description will be most useful
when you are first learning about the DX-10 transmitter.
Most of the blocks on the block diagram represent printed circuit
boards in the DX-10 Transmitter, and if you look at the DX-10
Overall Schematic Diagrams, you will find many of the same
blocks as printed circuit boards.
Nearly all printed circuit boards are described in detail in sections A through R in this technical manual. Some circuits not
located on printed circuit boards and a few printed circuit boards
with simple circuits are described in the last part of Section 4.
4.3.1 RF Section
The RF Section includes the Oscillator through the Power Amplifier (48 RF Amplifiers), Bandpass Filter, and Tee Matcher.
The RF section generates an RF signal, then several amplifier
stages increase the power to a level high enough to drive the
Power Amplifier stage. The RF amplifier outputs are combined,
4-2
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 4-1
DX-10 Block Diagram
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-3
Figure 4-2
Turn-on/Turn-off control logic.
4-4
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 4-3
Control section block diagram.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-5
Figure 4-4
RF Flow block diagram.
4-6
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 4-5
Audio and Modulation block diagram.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-7
and go through a Bandpass Filter/Output Network to a 50 ohm
RF output point. A Tee Matcher allows convenient matching to
loads that are not exactly 50 ohms.
Most RF section components are on printed circuit boards. RF
Amplifiers are on small, plug-in printed circuit board modules
which can easily be replaced in case of faults. The RF section
uses all solid state switching RF amplifiers, and an “RF Sense”
feedback signal to the Driver Supply Regulator forms a kind of
AGC loop which controls RF drive level to the Power Amplifier.
4.3.1.1 Oscillator
The oscillator board includes a crystal oscillator with two crystals. Either crystal can be selected with a jumper plug. The
oscillator board also includes jumper plugs and circuits for an
external oscillator input. The most common use of the external
oscillator input will be for AM Stereo operation. Additional
inputs and outputs are provided if the DX-10 is part of a 20
kilowatt combined transmitter installation (the external oscillator input will not be used in a combined transmitter). Jumper
plugs also allow easy conversion to combined transmitter operation. The Oscillator board is located in the non-interlocked
compartment for easy access and
troubleshooting, if required.
4.3.1.2 RF Amplifier Stages
A plug-in Buffer Amplifier module amplifies the oscillator
output, then Pre-Driver and RF Driver stages amplify the RF
signal further to drive the Power Amplifier. The pre-driver and
RF driver use plug in RF Amplifier Modules which are identical
to the 48 plug-in power amplifier modules, and can be interchanged with them. The pre-driver uses one plug-in module and
the RF driver uses three plug-in modules.
4.3.1.3 Driver Supply Regulator
The Driver Supply Regulator is part of a loop which controls RF
drive level to the power amplifier. An “RF Sense” feedback
signal from the RF splitter controls a regulator output voltage
which controls RF driver output.
4.3.1.4 RF Status Indications: RF Sense Data Lines
Three RF status indicators on the transmitter status panel indicate
Oscillator, Buffer Amplifier, or Pre-Driver and faults if an RF
Under drive fault turns the transmitter off. These indications can
quickly direct you to the faulty section. The RF Sense outputs
go to circuits in the controller which operate the RF indicators.
4.3.1.7 Power Amplifier
The Power Amplifier includes 48 plug-in modules. For Quantized Amplitude Modulation, or “digital amplitude modulation,”
encoded Audio signals from the Modulation Encoder to each RF
amplifier module turn on as many modules as required at any
instant by the modulating signal and unmodulated transmitter
output. The number of “Steps” available is much, much larger
than 48, because six of the RF amplifier modules are “Binary”
fractional-power modules. The description of “Digital Modulation” in this section describes this process in more detail.
4.3.1.8 Combiners, Output Network and Output Circuits
The 48 RF amplifier module outputs are combined in the three
Combiner sections. A Bandpass Filter matches the low Combiner output impedance to 50 ohms; there are no operator controls in the Bandpass Filter/Output Network. The Bandpass
Filter also smooths the small steps that remain in the power
amplifier output.
The output network is factory-tuned to match a resistive 50 ohm
load (an impedance of 50 + j0 ohms). Because antenna systems
and other loads are often do not present exactly a (50 + j0) ohm
load, the “Tee Matcher” includes controls labeled “Tune” and
“Load” to match the load to 50 ohms. The Tee Matcher is
configured as a low-pass filter to attenuate harmonics and also
includes a third harmonic trap.
The Output Monitor board includes “Antenna” (load) and
“Bandpass Filter” VSWR Detectors, directional couplers for
monitoring forward and reflected power. The VSWR Detectors
use phase detectors to provide very rapid VSWR sensing which
will turn the Power Amplifier off in one microsecond or less.
4.3.2 Audio Input and Modulation Section
The Modulation section of the DX-10 accepts an analog audio
input signal, converts it to a digital signal, and processes the
digital signal to control the turn-on and turn-off of PA stages. In
addition, a digital power control signal from the Controller board
to the Audio Input board determines the unmodulated power
output. Printed circuit boards in the Modulation section include
the Analog Input (Audio Input) Board, Analog to Digital Converter board, and Modulation Encoder board.
4.3.1.6 Combiner and Splitter
The audio input board accepts the audio modulating signal and
“processes” it, basically rolling off high audio frequencies, adding a DC component to determine the maximum unmodulated
transmitter output (maximum carrier power), then attenuating
the (audio + DC) signal to set transmitter output power. The
attenuator setting, and therefore the transmitter output power, is
determined by a digital power control signal from the Controller
board (A38) in the Controller section. The digital power control
signal is set with the transmitter’s High, Medium, Low, Raise,
and Lower controls.
The outputs of the three RF driver amplifier modules are combined in the Driver Combiner. The driver combiner output goes
to the RF Splitter input, and the RF splitter provides separate RF
drive signals to each of the 48 Power Amplifier RF amplifier
modules.
An (audio + DC) sample from the Analog Input board goes to
the DC Regulator, where it modulates the regulator’s “B-” output
voltage. The Modulated B- is effectively a bias voltage for the
RF Power Amplifier transistors (MOSFET’s) to optimize distortion and noise performance.
4.3.1.5 Status Indications as Troubleshooting Aids
The status panel indicators are normally green, but the indicator
for the board where RF is lost indicates red to direct you to the
most likely cause of the fault. Each RF amplifier board has fuses,
and if an amplifier fault causes a fuse to open, a red LED will
illuminate to indicate the location of the open fuse.
4-8
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
The A/D (Analog to Digital) Converter board converts the (audio
+ DC) signal into a 12 bit digital audio signal. The DC + Audio
signal is sampled at a rate between 400 and 800 kilohertz (about
once every 1.2 to 2.5 microseconds). (Sampling rate depends on
transmitter operating frequency).
supplies most RF amplifier modules in the the Power Amplifier
Section, and the +115 VDC is the supply voltage for the RF
Driver section and some Binary Amplifier stages in the Power
Amplifier.
The Modulation Encoder converts the 12-bit digital audio information into control signals which turn the RF power amplifier
modules on and off, as required by the transmitter carrier power
level and the instantaneous modulation level. Also, whenever a
high VSWR condition is detected, a PA KILL signal from the
Output Monitor board directly to the Modulation Encoder turns
all PA RF amplifier stages off within a few microseconds.
The Low Voltage Supply provides several unregulated DC voltages: +60 VDC, +30 VDC, +22 VDC, -22 VDC, +8 VDC, and
-8 VDC. The low voltage supply also provides 24 Volts AC to
operate the High Voltage Supply primary contactors and the
relays used in the Interlock circuits.
4.3.3 Controller Section (“Controller” and “LED”
Boards)
The Controller Section consists of two printed circuit boards, the
Controller board (A38), and the LED board (A32). The Controller Section includes:
a. Turn-on/turn-off control logic, on the Controller Board.
Operator commands turn the transmitter ON, or, if the
transmitter was operating when AC power failed, it is
automatically turned ON and restored to the same operating condition when power returns. Operator commands or
faults and overload turn the transmitter OFF.
b. Power Control logic, also on the Controller Board, uses
High, Medium, Low, Raise, and Lower control inputs to
generate digital power control signals for the digitally
controlled attenuator on the Audio Input board. Power
Control Logic also “remembers” the last power set for
each power level (High, Medium, or Low) so that when
the power level is selected again the transmitter will go to
the preset power output. Status outputs illuminate the five
front panel push buttons and provide remote status outputs
at the external interface.
c. The LED Board contains fault and overload sensing and
logic. It provides 26 LED Status Panel indications and
“Remote” or “Local” status indications, as well as providing all these status indications as remote status outputs at
the external interface. Many status indications are latched,
to provide fault indications until they are “reset,” even if
the transmitter is turned off. Latched indications are also
“remembered” as long as a backup supply voltage is
present when AC power is turned off or fails.
4.3.4 Transmitter Power Supplies
The DX-10 Transmitter contains two unregulated power supplies, a Low Voltage supply and a High Voltage supply, both
located in the transmitter’s Power Supply compartment. Regulated voltages used in the transmitter are derived from these two
supplies. Voltage regulators include the Driver Supply Regulator
(A22), the DC Regulator (A30), and voltage regulators on many
other printed circuit boards.
4.3.4.1 High Voltage Supply
The High Voltage Supply provides two unregulated voltage
outputs, +230 volts DC and +115 volts DC. The +230 volts DC
03/16/2009
4.3.4.2 Low Voltage Supply
4.3.4.3 Driver Supply Regulator, A22
The driver supply regulator provides a regulated voltage, controlled by the “RF sense” feedback signal, to one RF driver
section and also distributes unregulated +115 VDC to the other
two driver sections. It operates in either an “Open Loop” or a
“Closed Loop” mode. In the “Closed Loop” mode, it automatically controls RF drive level to the power amplifier. The “Open
Loop” mode allows only manual control of drive level, and is
used during transmitter tune-up.
4.3.4.4 DC Regulator Board, A30
The DC Regulator board supplies +5 VDC and a Modulated
B-voltage to the Modulation Encoder. The board contains the
two voltage regulators, and also contains Contactor Drivers for
the High Voltage Supply AC primary contactors.
The Controller board contains a +5 volt backup power supply
(+5B supply) which maintains supply voltage to selected latch
or memory circuits when the AC primary power is turned off.
The backup supply maintains data for at least two hours using
an internal energy storage capacitor, or the backup supply can
be maintained indefinitely by installing three optional “AA” size
batteries.
4.3.5 External Interface
The External Interface provides remote “control inputs,” status
outputs, and selected metering outputs. The External Interface
Board isolates transmitter circuits from connections at Terminal
Boards TB1 and TB2 to minimize the possibility of damage to
transmitter circuits if improper voltages are accidentally applied
to the terminal boards.
4.4 Digital Terms and Concepts
The discussion of Analog to Digital and Digital to Analog
Conversion will include some terms, abbreviations, and concepts used in this Technical Manual which may not be familiar
to some Broadcast Station engineers and technicians. Most terms
will be explained in the discussion, but a summary is also
included here for review or reference.
a. ANALOG refers to something that has a continuous range
of values, rather than changing in steps. Examples of
analog signals are the audio signals from a microphone, a
turntable cartridge, or a normal tape playback head.
b. DIGITAL is related to digits, or discrete quantities. An
analog signal changes continuously, but a digital signal
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-9
changes in steps. An analog signal has an infinite number
of possible values, and a digital signal has a finite, or
limited, number of possible values.
c. BINARY: Has only two possible values. A Binary
Number is a number represented using only the digits 0
and 1. This is useful in electronic circuitry because a circuit
can be ON or OFF (two states). A logic signal may be one
of two different voltages, referred to as HIGH (binary 1)
or LOW (binary 0) in this Technical Manual.
d. BINARY can also refer to a series where each step is either
multiplied or divided by two to get the next step. An
example, in the DX-10 Transmitter, are the Binary RF
combiner steps, which are 1/2 step, 1/4 step, 1/8 step, and
1/16 step. In this series, each step is divided by two to get
the next step. A Binary series could also be 1, 2, 4, 8, 16,
etc.
e. BIT: A Binary digit, 0 or 1.
f. DIGITAL WORD: A Digital Word is a series of numbers,
or a group of bits, representing a complete piece of digital
information. The term “Digital Word,” when used here,
will always refer to a binary number, which is a series of
ones and zeros. The number of BITS in a Digital Word is
the total number of digits (ones and zeros). Examples of a
six bit digital word are “010010" and ”110101." A 12 bit
digital word is “0100 1000 1101.”
g. MSB: Abbreviation for MOST SIGNIFICANT BIT. In a
digital word, as in a decimal number, the first digit
represents the largest change, and is the MSB.
h. LSB: Abbreviation for LEAST SIGNIFICANT BIT. In a
digital word, as in a decimal number, the last digit represents the smallest change, and is the LSB.
i. BIT 1, BIT 2, etc.: In a 12-bit digital word, the bits are
numbered from 1 through 12, where Bit 1 is the MSB, and
Bit 12 is the LSB.
j. BINARY CODED DECIMAL: (Abbreviated as BCD).
Each number in the decimal number system, from 0
through 9, is represented by a 4-bit binary number. Example: In the BCD system used in the power command
Encoder and Decoder in the DX-10, “567" is represented
as ”0101 0110 0111."
k. A/D: Also written “A to D.” Abbreviation for “Analog to
Digital.”
l. D/A: Also written “D to A.” Abbreviation for “Digital to
Analog.”
m. ADC: Abbreviation for “Analog to Digital Converter.
n. DAC": Abbreviation for “Digital to Analog Converter.
Some Basic Digital Circuit Concepts, which will be used in the
following discussion and in circuit descriptions, are also included for review or reference.
In logic circuits, representing a digit by either zero or one is
useful because it can be represented by a switch or a circuit that
is either “off” or “on.” The digits “zero” and “one” may also be
represented by a voltage that is LOW for “zero” and HIGH for
“one.”
4-10
In circuit descriptions and on schematic diagrams, the terms
“logic LOW” and “logic HIGH” are used. These terms may also
be represented by the letters “L” and “H,” particularly on schematic diagrams. In most of the digital logic circuits in the DX-10,
normal TTL (transistor-transistor logic) levels are used, and a
“logic LOW” is represented by a voltage near zero (between
approximately zero and one volt), and a “logic HIGH” is represented by a voltage near +5 volts (between approximately +3.5
and +5 volts).
On block diagrams and on schematic diagrams in this Technical
Manual, when a signal description is followed by “-L” or “-H,”
the letter indicates the logic state when the signal is ACTIVE.
Examples: “RESET-L” indicates that when the signal is logic
LOW, a RESET will occur, or a RESET command is being
given. “VSWR-H” indicates that when the signal is logic HIGH,
a VSWR fault has occurred.
A Digital Word can represent only a definite number of quantities or steps, depending on the the number of bits in the digital
word.
a. If n = the number of bits in the digital word, then:
b. 2n = the number of quantities that may be represented by
that word.
For example, if a digital word has 5 bits, it may represent 25=32
quantities. If a digital word has 6 bits, it may represent26=64
quantities. If a digital word has 12 bits, it may represent212=4096
quantities.
“VALUE” OF EACH BIT: The least significant bit (LSB)
represents one unit. The next least significant bit represents two
units. The most significant bit represents 2n-1 units. Example: In
a 5 bit digital word":
•
•
•
•
•
Bit 1 (MSB) represents 16 units
Bit 2 represents 8 units
Bit 3 represents 4 units
Bit 4 represents 2 units
Bit 5 (LSB) represents 1 unit.
4.5 Quantized Amplitude Modulation
The DX-10 uses a new technique, patented by Harris Corporation, for producing an amplitude modulated RF signal. This
technique has been described as “Quantized Amplitude Modulation,” and also as “Amplitude Modulation Using Digitally
Selected Carrier Amplifiers.” Because the modulation section of
the transmitter uses a digital signal, the term “Digital Modulator”
is also used.
The terms “Digital Modulation,” “Digital Modulator,” and
“Digital AM Transmitter” are also used to describe the DX-10.
For the DX-10, these terms refer to the digital, or quantized,
modulation technique. The modulating signal is an analog audio
signal. The transmitter’s output signal is indistinguishable from
any other AM Broadcast transmitter except that the DX-10
provides low distortion and high audio quality.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
The basic principles of this new modulation technique are not
difficult to understand, especially if we first review some basic
principles of amplitude modulation and digital electronics technology. A basic discussion is included in the following paragraphs, as an introduction or review for technical personnel who
are not familiar with A/D and D/A conversion techniques. This
discussion will provide a background for a discussion of these
sections of the DX-10 Transmitter.
4.5.1 Amplitude Modulation - A Review
An amplitude modulated (AM) signal, as used in radio broadcasting, is a constant-frequency RF signal whose amplitude
varies with an audio input signal. The constant-frequency RF
signal is referred to as the carrier wave, and the audio input signal
which varies the amplitude of the transmitter output is called the
modulating signal.
If the RF output of an AM transmitter is monitored or observed
on an oscilloscope, the modulation envelope (the “outline” of the
modulated RF waveform) is the audio modulating signal.
With modulation the output voltage of an AM broadcast transmitter changes from instant to instant, depending on the audio
input. When a positive peak occurs in the audio modulating
signal, there is a HIGH RF voltage at the transmitter output. If
there is a +100% modulation peak, the transmitter’s RF output
voltage is twice the carrier (unmodulated) RF output voltage.
When a negative peak occurs in the audio modulating signal,
there is a LOW RF voltage at the transmitter output. If there is a
100% negative peak, the transmitter output at that moment is
zero.
With no audio signal, or at the moment that the audio signal
voltage is zero, the transmitter power output is its “carrier
power.” For the DX-10 Transmitter, this is nominally 10 kilowatts but can be adjusted to power levels from 1 kW through 11
kW. (DX-10 power output can be adjusted to less than 1 kilowatt,
but with increased distortion and noise).
“Modulation percentage” describes changes in RF VOLTAGE.
Note that when the RF output voltage changes, the power output
of the transmitter also changes. When the impedance of the
transmitter load is constant, the power is proportional to the
square of the voltage. For example, at the instant that modulation
is 100% positive, the RF voltage at the transmitter output is two
times the unmodulated, or carrier, voltage, and the power at that
instant is four times the unmodulated, or carrier, power.
In most AM broadcast transmitters, the RF output is varied with
modulation by changing an operating voltage on an RF amplifier. Changing the plate voltage of a vacuum tube amplifier or
the collector voltage of a transistor amplifier have been the most
common methods of producing an amplitude modulated signal.
4.5.2 Amplitude Modulation in the DX-10 Transmit-
ter
The following paragraphs provide an introduction or overview
of the amplitude modulation process in the DX-10 Transmitter.
The DX-10 power amplifier section uses a total of 48 separate
solid-state RF power amplifiers. Each individual RF power
03/16/2009
amplifier can be switched on and off very quickly. The power
outputs of the 48 RF power amplifiers, or stages, are combined
to produce the total transmitter power output.
Recall that the output of an AM broadcast transmitter is an RF
voltage which varies up and down, according to the audio
modulating signal input to the transmitter. In the DX-10, each
RF amplifier provides a fixed voltage. Any desired transmitter
output from zero (100% negative modulation peak) to the output
required by a large positive modulation peak can be produced by
switching the appropriate number of amplifiers ON. Switching
more amplifiers ON increases the transmitter’s RF voltage output. If the audio signal increases, more amplifiers can be
switched on. If the audio signal decreases, some of the amplifiers
can be switched off. As the audio signal changes from instant to
instant, the number of RF amplifiers that are switched ON also
changes.
For a positive modulation peak, which requires a high RF voltage
(and power) at the transmitter output, a large number of amplifiers are switched on. For a 100% negative modulation peak,
which corresponds to zero transmitter RF voltage (and power)
output, all the amplifiers are switched off. With no modulation,
when the transmitter output is the carrier power, only enough
power amplifiers to produce the required power are switched on.
4.5.2.1 Summary
Amplitude modulation in the DX-10 Transmitter is done by
turning on only enough power amplifier modules at any time to
produce the transmitter RF output required by the audio modulating signal at that moment.
The DX-10 Transmitter power amplifier section contains a total
of 48 RF power amplifier stages. This total includes 42 identical
“BIG STEP” amplifiers, and six “BINARY STEP” amplifiers.
The six Binary Steps are 1/2 step, 1/4 step, 1/8 step, 1/16 step,
1/32 step, and 1/64 step. As the 42 “BIG STEP” amplifiers are
turned on and off, the transmitter RF output changes in equal
VOLTAGE steps, not in equal power steps, because of operating
characteristics of the output power combiner.
The audio modulating signal must be converted into a signal to
control turn-on and turn-off of individual RF amplifier stages. In
the DX-10 Transmitter, the audio input signal is converted into
a digital signal which is then used to control the number of RF
amplifier stages that are switched on.
If you refer Figure 4-1, a DX-10 Transmitter Block Diagram,
you can see that there are two signal paths to the Power Amplifier
section. One is an RF signal path, and the other is an audio signal
path (including the digital audio signal).
The RF signal path includes an oscillator, RF amplifiers, and an
RF driver section which produces enough power to drive all the
individual power amplifier modules, an RF power splitter to
drive the 48 Power Amplifier modules, the 48 RF power amplifier modules which can be individually switched on or off, an
RF power combiner, and a bandpass output network.
The audio signal path includes an audio input section, a highspeed analog to digital converter, and a modulation encoder
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-11
which provides the signals to turn individual RF amplifiers on
and off.
In the DX-10 the analog audio signal is converted into a digitized
audio signal by an Analog to Digital Converter. The digitized
audio signal is then processed by the modulation encoder to
provide signals to turn individual RF power amplifier stages on
and off. The RF power amplifier section converts the encoded
digital signal directly into a high power, amplitude modulated
RF output signal.
Before continuing with a description of DX-10 Transmitter
circuits, the Analog to Digital (A/D) and Digital to Analog (D/A)
conversion processes will be reviewed. This review will provide
a background for discussing the transmitter’s modulation section.
4.6 Analog to Digital Conversion
The Analog to Digital (A/D) conversion process takes place in
three steps:
1. Divide the time scale into equal intervals.
2. At each time interval, the amplitude (voltage) of the
analog signal is sampled and recorded.
3. For each recorded sample, a digital word is constructed
that represents the analog sample.
In the following explanation of these steps, the numbers used do
not represent voltages used in the DX-10, but are used only as
an example.
a. Divide the time scale into equal intervals.
The analog input signal is a signal which changes with time. (In
the DX-10, this is an audio signal). Each interval or division will
be a “sample interval.”
a. Sample and record the analog signal.
The analog to digital converter takes a finite amount of time to
convert the analog signal into a digital word. The input to the
analog to digital converter should not change during the time that
the conversion is taking place. It is necessary to sample the
voltage, then store or record it during the conversion. The signal
is sampled at the beginning of the time interval.
a. For each sample point, construct a digital word that best
approximates the analog sample.
A digital word is represented by a series of zeros and ones. Each
digit in the digital word is called a “BIT.” Each digital word
represents a range of analog voltages.
If a five-bit digital word is used, there are 32 possible words,
from “00000" to ”11111." The total analog voltage range, then,
is divided into 32 equal voltage ranges and each digital word
represents one of these voltage ranges. Table 1 shows some
voltage ranges and five-bit digital words for a 0.00 to +8.00 volt
signal. Each digital word represents a range of voltages of
(8.00/32=0.25) volt.
4-12
For each time interval in Step 1 (for each “sample interval”), the
digital word corresponds to the voltage at the beginning of the
time interval, because the analog signal is sampled at the beginning of each time interval. Note that the analog signal amplitude
has Infinite precision (many decimal places), but the digital word
has a finite word length, and each digital word length represents
a range of voltages. This results in a roundoff or quantization
error. For the 5 bit digital word in the example, the roundoff error
could be as large as 0.25 volts.
If a longer digital word had been used (more bits in the digital
word), the roundoff or quantization error would be smaller. For
example, if the digital word length were 8 bits, it could have any
of 256 values (from 0000 0000 through 1111 1111). For an
analog signal varying from 0.000 volts through +8.000 volts,
“0000 0000" would now represent voltages from 0.000 through
+0.03125 volts; ”1000 0000" would represent voltages from
4.000 through 4.03125 volts, and so on. By increasing the digital
word length from 5 bits to 8 bits, the maximum roundoff or
quantization error would be reduced from 0.25 volts to 0.3125
volts.
A 12 bit digital word could have any of 4096 values, from
0000\0000\0000 through 1111\1111\1111, and would have a still
smaller quantization error. As the quantization or roundoff error
becomes smaller, the series of digital words represents the analog signal more closely.
A key point in Analog to Digital Conversion, then, is:
THE MORE BITS THERE ARE IN THE DIGITAL WORD,
THE MORE ACCURATE THE REPRESENTATION OF THE
ANALOG SIGNAL WILL BE.
The RESOLUTION may be expressed as the number of bits in
the digital word. If “n” is the number of bits, the number of steps
represented by a digital word is (2n-1) when the “zero” step is
not counted. For a 5 bit word, 25-1 = 31 steps; for an 8 bit word,
28-1 = 255 steps; and for a 12 bit word 212-1 = 4095 steps.
4.6.1 SAMPLE TIME INTERVAL
The sample time interval used must be short enough so that each
significant change in the analog signal is represented by a new
digital word. A rough “rule of thumb” is that the sample frequency should be at least two times the highest frequency.
Higher sample frequencies will reproduce the analog signal
more accurately. (The sample time interval, “t” is the inverse of
sample frequency “f” so that t=1/f.)
The sample time interval must also be long enough to allow the
analog to digital conversion process to take place. The high
speed A/D converter used in the DX-10 requires about 0.9
microseconds (900 nanoseconds) for a conversion.
In the DX-10 Transmitter, a 12 bit analog to digital converter
(ADC or A/D converter) is used for high resolution. The effective resolution of the digital to analog conversion (DAC or D/A
conversion) process in the DX-10’s RF power amplifier stage is
about 11.4 bits, or about 2,800 steps (211.4 is approximately
2800). RF power amplifier resolution is less than 12 bits because
a true binary D/A converter is not used; this will be explained
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
later. The sample frequency in the DX-10 is between 400 kHz
and 820 kHz, depending on the transmitter carrier frequency.
4.7 Digital to Analog Conversion
The digital to analog conversion process (D/A conversion) is
simply the reverse of the analog to digital (A/D) process, and
takes place in two steps:
Re-create the analog voltage represented by the digital word by
turning on or off units of DC voltage (or RF voltage) and holding
it constant for one time interval.
1. Pass the reconstructed audio through a low pass filter
to remove the steps. This low pass filter is also called a
reconstruction filter, and acts as a “smoothing filter.”
The reconstruction filter can regain much of what was
lost in quantization.
• STEP 1: Re-create the analog voltage represented by the
digital word. Each bit of the digital word represents some
amount of voltage. For a five bit digital word and an analog
voltage range of zero to eight volts (used in Table 1), each
bit represents a voltage as follows:
Bit 1, 4.00 volt (MSB)
represented by the least significant bit becomes smaller, the steps
in the re-created analog voltage from the D/A converter become
smaller, and the re-created voltage more closely approximates
the original analog voltage.
• STEP 2: Pass the reconstructed audio through a low pass
filter to remove the steps. Because the low pass filter
smooths the steps, it may be called a “smoothing filter”; it
is also called a “reconstruction filter” because it reconstructs a better approximation of the original audio signal
from the stepped output of the D/A converter.
Sharp “corners,” steps, or transitions in a waveform are caused
by high frequency harmonics in the signal. The low pass filter
attenuates or removes these harmonic frequencies, and therefore
also smooths or removes the sharp corners or steps in the waveform.
The Digital to Analog converter output can be any desired
voltage, limited only by the switching circuits in the converter.
For example, the bits in the digital word could be used to switch
voltages of 100, 50, 25, 12.5, and 6.25 volts, so that the digital
word 00101 would produce a D/A converter output of (25 + 6.25)
= 31.25 volts, instead of (1.00 + 0.25) = 1.25 volts as in the
example. The bits in the digital word can also be used to switch
Radio Frequency signal voltages on and off to produce a varying
or amplitude modulated RF signal.
Bit 2, 2.00 volt
Bit 3, 1.00 volt
Bit 4, 0.50 volt
4.8 DX-10 Power Amplifier Section Prin-
Bit 5, 0.25 volt (LSB)
Note that the Most Significant Bit (MSB) represents one-half of
the maximum analog voltage, and each additional bit represents
one-half of the voltage of the bit before it.
The analog voltage can be reconstructed by providing a voltage
source, either DC or rf, for each of the voltages represented by
bits in the digital word, then using these voltages as inputs to a
summing circuit with a switch to turn each voltage OFF if the bit
is zero or ON if the bit is one.
An example from Table 4-1 will be used to illustrate this process.
When the input to the A/D converter is +3.914 volts, the digital
word constructed is 01111. The D/A converter, then, sums (2.00
+ 1.00 + 0.50 + 0.25) for a total of 3.75 volts. If the digital word
is 00101, the output of the D/A converter is (1.00 + 0.25) = 1.25
volts.
The least significant bit in the digital word represents 0.25 volts
in this example, so that the output of the D/A converter must
change in 0.25 volt steps. Note that this is the same as the 0.25
volt quantization error in the example of the Analog to Digital
conversion used in the previous section.
The analog input voltage to the Analog to Digital converter
changes in continuous manner, but the output of the Digital to
Analog converter changes in steps. The re-created voltage at the
output of the D/A converter is an approximation of the original
analog input voltage. The maximum roundoff or quantization
error in the re-created analog voltage is the size of the steps. As
the number of bits in the digital word increases, the voltage step
03/16/2009
ciples
In the DX-10 Transmitter power amplifier, the digital information which is constructed by the A/D converter is used to switch
units of RF voltage on or off by switching RF power amplifiers
on and off. The output combiner sums all the individual units of
voltage.
The RF power amplifier in the DX-10 Transmitter may be
thought of as a Digital to Analog converter, where the Analog
output signal is a high power, amplitude modulated, RF signal.
The combined action of the RF power combiner and power
amplifiers used in the DX-10 produces RF VOLTAGE steps at
the power combiner output, not RF power steps. The power
output of each RF amplifier stage in the PA section depends on
the total number of stages switched on. If a small number of
stages are switched on, each stage has a small power output. If
a large number of stages are switched on, each stage has a larger
power output. Switching on twice as many RF amplifier stages
will produce twice the VOLTAGE output (and four times the
power output).
AM transmitter PEAK output power requirements are much
greater than the transmitter CARRIER power. Also, broadcasters in the United States normally require some additional transmitter power output to overcome antenna system power losses.
For this reason, the carrier power output of the DX-10 is rated at
up to 11 kW. The positive peak modulation capability of an AM
broadcast transmitter depends on the maximum peak power
output available from the transmitter. Recall, for example, that
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-13
Table 1. Example of Analog to Digital Conversion.
ANALOG VOLTAGE RANGE
DIGITAL WORD
from 0.00 through +0.25 volts
from +0.26 through +0.50 volts
from +0.51 through +0.75 volts
from +0.76 through +1.00 volts
00000
00001
00010
00011
from +3.76 through +4.00 volts
from +4.01 through +4.25 volts
from +4.26 through +4.50 volts
01111
10000
10001
from +7.26 through +7.50 volts
11101
from +7.51 through +7.75 volts
from +7.76 through +8.00 volts
11110
11111
a +100% modulation peak represents a peak output power of four
times the carrier power, or 40 kW for a 10 kW transmitter. With
a carrier power of 11 kW, a 125% positive peak requires a peak
output power of 55.7 kW.
In a binary sequence D/A converter, as we have described, the
RF voltage corresponding to the most significant digit in the
digital word must be one-half of the peak voltage. In an RF
voltage combiner, all RF voltages are added in series so the same
current flows through all outputs as through the load, and onehalf the peak voltage is also one-half the peak power. The largest
step, then, would have to be able to deliver about 28 kilowatts,
the next, 14 kilowatts, and so on. It is more practical to use a
larger number of smaller power amplifiers.
The RF power amplifier (PA) section in the DX-10 is a digital
to analog converter, with a high power modulated RF output.
Recall again that the RF power combiner and RF power amplifier
stages act to produce EQUAL RF VOLTAGE STEPS Normally,
the steps in the PA section output are too small to observe on an
oscilloscope, unless some amplifier stages are faulty.
The term “STEPS” in the following discussion of the DX-10 RF
power amplifier will refer to RF output VOLTAGE steps.
The DX-10 Power Amplifier section uses a total of 48 RF
amplifier stages or modules, which are all combined in an RF
power combiner. A total of 42 RF amplifier stages each produce
identical RF voltage steps as they are switched on and off. The
modulation encoder converts the digital audio information into
on/off signals for these 42 RF amplifier stages.
The 42 steps do not provide nearly enough resolution for high
quality audio reproduction, and the six remaining RF amplifier
stages provide smaller steps, in a binary sequence (1/2, 1/4, 1/8,
1/16, 1/32, and 1/64 steps).
In addition, still more effective resolution is provided by adding
a “Dither” signal (refer to section J, Analog Input Board, for
more information on the “Dither” signal.
4-14
4.8.1 “BIG STEPS” and BINARY STEPS
The 42 identical steps in the DX-10 output are called “BIG
STEPS,” and the smaller, binary sequence steps are called “BINARY STEPS.” Each of the 42 Big Step amplifier stages is
numbered, from 1 through 42. Amplifier stage 1 is the first to
turn on when going from zero output to the first step output, and
amplifier stage 42 turns on only at very high positive modulation
peaks. (Recall that a modulated RF output waveform can vary
from zero, with -100% modulation, to the peak voltage required
by the maximum peak modulation capability of the transmitter.)
The Binary Steps are switched directly by bits 7, 8, 9, 10, 11 and
12 of the 12-bit digital word. The first six bits, which are the six
most significant bits (MSB’s) control (26-1) = 63 steps, but only
42 steps are used in the DX-10, so the total number of steps is
less than (212-1) = 4095 steps.
The DX-10 power amplifier has a total of approximately 2,800
steps, and use of the “dither” signal effectively provides additional resolution. The resolution provided gives low-distortion
audio performance, with modulation capability from over
+125% to -100% at an 11 kW carrier power level.
4.8.2 Modulation Encoder
In the Modulation Encoder, the first six bits (the six MSB’s) are
converted into 42 control signals, one for each of the 42 Big Step
amplifiers. The control signals from the modulation encoder
output turn the 42 amplifiers on and off. The modulation encoder
uses Read Only Memories (ROM’s) for the encoding function.
The six MSB digital word addresses memory locations in the
ROM’s, and the information stored in each set of memory
locations turns on the required Big Step amplifiers.
4.8.3 RF Output Bandpass Filter
The small steps that remain in the amplitude modulated RF
output of the PA section result in undesirable RF sideband
frequencies. Passing the AM signal through a bandpass filter
attenuates these sideband components, smoothing out the steps.
The Digital to Analog conversion process also produces “replicated spectra,” which are mathematically predictable signals at
frequencies other than the desired output frequencies. The choice
of sampling frequencies for the Digital to Analog converter is
determined partially by the requirement that replicated spectra
components fall outside the pass frequency range of the bandpass
filter.
The Bandpass Filter is located in the signal path between the
output power combiner and the transmitter RF power output. It
functions as the “smoothing filter” or “reconstruction filter,” in
addition to providing impedance matching and attenuation of
harmonics and any other spurious frequencies.
4.8.4 Switching RF Amplifiers ON or OFF
How do we switch individual RF power amplifiers on or off? In
the DX-10, the input drive to each amplifier is turned on or off.
The RF input drive is turned on or off with a solid state switching
circuit. Because the switching circuit is done with low voltage,
low current circuits, very little power is consumed in the switching process.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
4.8.5 RF Combiner
The summing, or combining, of the RF amplifier outputs is done
in a transformer combiner. Each primary winding of the combiner connects to the output of an RF amplifier, and the one-turn
secondary “windings” of all the combiner transformers are connected in series.
Each secondary “winding” is a straight copper rod. For a toroidal
transformer, one turn means that the conductor passes through
the center of the toroid once; a straight conductor, therefore, is a
one-turn secondary winding. Each toroid, with its primary winding, induces a voltage in its segment of the copper rod, and
because the straight rod passes through all toroids, the voltages
in the segments of the rod add together.
4.9 Summary: DX-10 Digital Modulation
The amplitude modulation process in the DX-10 takes place in
three steps. First, The audio input signal is converted into a
digital data stream, which is a series of 12 bit digital words, in
an Analog to Digital Converter. This digital data stream is a
“digital audio” signal. Second, the digital data from the A/D
converter is encoded in a modulation encoder to provide the
digital signals required by the power amplifier section. Third, the
digital output of the modulation encoder is used to switch individual RF amplifiers on or off. The individual RF amplifier
stages are all combined in an RF power combiner. The RF
amplifier stages and combiner together make up a power amplifier section. Amplitude modulation of the power amplifier section output is produced by switching on varying numbers of
individual RF amplifier stages.
The RF output of the power amplifier section changes in very
small steps, or discrete quantities. The modulation process can,
therefore, be termed “Quantized Amplitude Modulation.” A
bandpass filter, following the power amplifier section, smooths
the steps.
4.9.1 Engineering Description
This section may also be summarized in engineering terms. The
power amplifier section of the DX-10 can be described as a
“Power multiplying digital-to-analog converter (DAC),” which
is capable of 10 kilowatts of carrier power. The Quantized AM
system consists of a 12 bit digital-to-analog converter (ADC), a
digital modulation encoder, and a power multiplying DAC. The
power DAC has an effective resolution of 11.4 bits (i.e. 2879
individual steps). The encoder converts the 12 bit digital audio
code into one which is compatible with the power DAC. The
quantized analog output of the DAC is multiplied by the radio
frequency (rf) waveform to form an amplitude modulated carrier
with a quantized envelope. The quantized AM waveform is then
filtered by a bandpass output network to remove the unwanted
spectral components.
The power multiplying DAC is implemented with an array of
solid state switch mode amplifiers. The RF signal is the common
drive to all of the amplifiers. The on/off status of each amplifier
03/16/2009
is controlled by the 12 bit digital audio signal. The control signals
turn on the proper number of RF amplifiers such that their sum
is the desired RF output signal.
4.9.2 Digital Modulation Characteristics
The patented Harris Digital Modulator in the DX-10 uses new
technology which produces a very high quality, low distortion
amplitude modulated signal for AM broadcasters. “Digital
Modulation” or “Digital Modulator” or “Quantized Amplitude
Modulation” all describe the new digital technique used in the
DX-10 to produce the amplitude modulated output signal.
Overall efficiency of the DX-10 is very high, because the digital
modulator uses very little power and the RF amplifiers are also
high efficiency solid-state switching amplifiers (Class D).
Many broadcasters today are concerned with producing a “loud”
signal. Audio processing equipment is used to maintain high
average modulation levels. A highly processed audio waveform
often begins to look like a square wave on audio peaks. It is
desirable, then, for a transmitter to be able to reproduce square
wave signals with little or no overshoot or tilt, so that the
loudness provided by the audio processing equipment is not lost.
The DX-10 Transmitter has little or no overshoot or tilt with
square wave modulation, even at very low audio frequencies.
Whether a broadcast station is interested in maintaining a lowdistortion audio signal, or wants to use a highly processed audio
signal for loudness, an AM broadcast transmitter should accurately reproduce the audio input signal with as little distortion,
square wave overshoot, or square wave tilt as possible. The
DX-10 Transmitter is very “transparent”; the modulation envelope accurately reproduces the audio input signal.
4.10 AC Power Circuits in the DX-10
The Overall Schematic Diagram shows AC Power Circuits in
the DX-10. Refer to the DX-10 Overall Schematic Diagram
839-6208-241 or 839-6208-282.
Incoming AC Power is connected to terminal board TB5, in the
Power Supply Compartment. AC Power input can be either
197-281 V Delta connected or 380-415 V Wye connected. Refer
to Section 2, Installation, for information on Delta and Wye
connections.
AC Power in the DX-10 is distributed, through fuses and contactors, to the three phase High Voltage Supply transformer T1,
three phase blower motor B1, and to single phase Low Voltage
Supply transformer T2. For a Delta Connection, the Low Voltage
supply transformer is connected between two phases; for a Wye
connection, it is connected between one phase and Neutral.
4.10.1 Transient Protection
Three MOV’s (Metal Oxide Varistors), RV1, RV2, and RV3,
absorb transient voltages on the incoming AC input. Fuses F1,
F2, and F3 protect the MOV’s in case of a voltage surge on
incoming power lines. The fuses should be checked as part of a
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-15
routine maintenance procedure, as one fuse (two fuses for Wye
connection) will not cause any supply voltage loss if it opens.
4.10.2 Overvoltage and Undervoltage Protection
There are no circuits specifically for AC Overvoltage or Undervoltage protection, but other transmitter circuits protect against
these conditions, by sensing high or low DC power supply
voltage conditions. The “Main Power Supply” DC overvoltage
protection on LED Board A32 will shut the transmitter off in
case of overvoltage conditions. IC voltage regulators on printed
circuit boards include protection against high or low regulated
output voltages (refer to section M, DC Regulator, for information on IC voltage regulators). If high or low supply voltages to
RF Driver circuits result in excessive RF drive level changes, RF
Overdrive or Under drive circuits on the LED Board also shut
the transmitter off.
4.10.3 “Brown-Out” Protection
A “brown-out,” or low AC line voltage, will cause a “Supply
Fault” on Controller Board A38, and the Supply Fault logic
signal will de-energize the high voltage supply contactor through
gate U52C (see Section P, Controller).
4.10.4 Phase Loss Protection
When the High Voltage supply is ON, a low or lost phase voltage
on the three-phase AC power input will cause a “Main Power
Supply: Supply Fault” which turns the transmitter off. The low
or lost phase activates the Power Supply Protection circuit on
LED Board A32. Refer to Section Q, LED Board, for a description of the Power Supply Protection circuit.
4.11 Transmitter Power Supplies
There are two power supplies in the DX-10, a Low Voltage
power supply and a High Voltage power supply. Both power
supplies are located in the transmitter’s power supply compartment. These two supplies provide all voltages used in the transmitter. Voltage regulators, including DC Regulator A30 and
voltage regulators on other printed circuit boards operate from
unregulated input voltages from the Low Voltage supply.
4.11.1 Turning Supplies ON and OFF
4.11.1.1 Low Voltage Supply
The Low Voltage supply is ON whenever rocker switch S11 is
ON and AC primary power is applied. (S11 is located in the front
non-interlocked compartment, at the bottom of the right hand
side). If S11 is OFF, the Low Voltage supply is OFF and there
is no power for transmitter control logic so the front panel push
buttons and remote control inputs can not operate.
NOTE
Remote Control and Transmitter front-panel push-button switches
will not operate if Low Voltage power supply switch S11 is OFF
(or if no primary power is applied). The Low Voltage supply will
normally be left ON except during maintenance.
4-16
WARNING
AC INPUT VOLTAGE IS STILL PRESENT IN THE POWER SUPPLY COMPARTMENT EVEN IF LOW VOLTAGE SUPPLY SWITCH
S11 IS OFF. REMOVE ALL PRIMARY POWER BY TURNING THE
WALL DISCONNECT SWITCH OFF BEFORE OPENING INTERLOCKED DOORS OR REMOVING REAR PANELS.
4.11.1.2 High Voltage Supply
Depress the LOW, MEDIUM, or HIGH push-button on the
transmitter panel to turn the high voltage supply ON (there is no
separate “ON” switch on the DX-10). A LOW, MEDIUM or
HIGH Remote Control input also turns the High Voltage supply
ON. The High Voltage Supply cannot be turned ON if the Low
Voltage supply is off or if there are open interlocks. Some other
“faults” also prevent the High Voltage supply from coming on.
Depress the transmitter’s OFF button to turn off the High Voltage supply. (The Low Voltage supply will remain ON).
4.12 Low Voltage Power Supply, Circuit
Description
The Low Voltage Power Supply uses full-wave bridge rectifiers
and tapped windings to provide six different unregulated DC
voltages (+8V, -8V, +22V, -22V, +30V, and +60V). Half of the
center-tapped winding for the +30/+60 volt supplies also provides 24 volts AC for high voltage supply contactors K1 and K2
and for interlock relays K3 and K4. All transmitter logic and
other circuits, except RF Power Amplifier and RF Driver modules, operate from the Low Voltage supply.
The +8V and +22V low voltage supply outputs are distributed
to individual printed circuit boards, where +5 and +15 volt
regulators, and zener diodes, provide required voltages for circuits on the boards. The +30V output operates the Buffer Amplifier and some Binary Step RF amplifier modules and also
provides a voltage for door and external interlock logic inputs
(see section P, Controller and Section M, DC Regulator). The
Predriver stage operates from +60V at most frequencies (+30V
is used for some frequencies).
The Low Voltage Supply is located in the transmitter’s Power
Supply compartment, on the outside wall. Filter capacitors for
+8V and +22V outputs are located on the inside wall of the
compartment.
Refer to Sheet 1 of the DX-10 Overall Schematic Diagram for
the following description.
4.12.1 Low Voltage Supply, Primary Power Circuit
Transformer T2 is a single phase transformer, with a tapped
primary winding for operation from different input voltages.
Refer to the Installation Section, Section 2, for information on
proper tapping of T2’s primary.
Circuit breakers CB1 and CB2 protect the supply against supply
faults, or overloads or shorts on the supply output. Fuses F1 and
F2 (or only F1 for Wye connection) protect the MOV’s, but if a
fuse opens the low voltage supply will shut down as well. Switch
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
S11 turns off the Low Voltage supply, but if your transmitter is
operated by remote control S11 MUST BE LEFT ON. Circuit
breakers CB1 and CB2 and switch S11 are located in the noninterlocked compartment, at the bottom of the compartment’s
right hand side wall. The fuses are located under the protective
metal cage on the power supply compartment’s outside wall.
WARNING
REMOVE ALL AC POWER FROM THE TRANSMITTER BEFORE
REMOVING THE PROTECTIVE CAGE IN THE POWER SUPPLY
COMPARTMENT. PRIMARY POWER CONNECTIONS ARE EXPOSED WHEN THE CAGE IS REMOVED.
Low Voltage Supply transformer T2 has two secondary windings. One winding provides 48 volts, center tapped, to bridge
rectifier CR15. The negative output of the bridge rectifier is
grounded, the bridge rectifier’s positive output is +60 volts
unfiltered, and the transformer winding’s center tap is +30 volts
unfiltered. One half of the winding also supplies 24 volts AC for
High Voltage supply contactors and interlock circuits; one side
of this 24 VAC circuit is the winding’s center tap, which is also
the supply’s +30 volt DC output.
The other secondary winding is tapped to provide two different
output voltages, using two different bridge rectifiers, CR13 and
CR14. The center tap is grounded, so that each bridge rectifier
“plus” terminal provides a positive output voltage and its “minus” terminal provides an equal negative voltage. CR13 provides
+8 volts and CR14 provides +22 volts.
Large electrolytic filter capacitors are used for all Low Voltage
supplies. Each capacitor has a bleeder resistor connected across
its terminals to discharge the capacitor when the supply is turned
off. Note that it will take several minutes to discharge the
capacitors if there are no other loads on the supplies.
4.12.2 Power Distribution Board, A39
The Power Distribution Board distributes +8V and +22V to other
transmitter printed circuit boards. The only components on the
Power Distribution board are seven Molex connectors. The
Power Distribution board is located in the Power Supply compartment, at the top front corner of the inside wall.
4.13 High Voltage Power Supply, Circuit
Description
The High Voltage Supply is also referred to as the “Main Power
Supply,” and provides +115 VDC and +230 VDC for RF Power
Amplifier modules and for the RF Driver. High Voltage supply
contactors K1 and K2 in the supply primary power circuit are
driven by transmitter logic circuits, and also provide a step-start
function on turn-on. Auxiliary contacts on K1 and K2 operate
the Power Supply Discharge board when the supply is turned off.
The High Voltage Supply is located in the Power Supply compartment. The supply transformer, T1, is located on the bottom
of the compartment. AC contactors are located inside the metal
cage on the outside wall. Step-start resistors are located at the
03/16/2009
top front of the outside wall, inside a protective metal cage.
Rectifiers are mounted on the inside wall. Filter capacitors are
located at the back of the inside wall. DC fuses, discharge diodes
and resistors across the fuses, and supply voltage sample circuits
are located on Fuse Board A24, located near the center top of the
inside wall. Figures 1-2 and 1-9*, in Section 1, are photographs
which show locations of major power supply components, and
a silk screen on the inside of the compartment’s interlocked front
door also shows locations of components in the compartment.
Refer to Sheet 2 of the DX-10 Overall Schematic for the following description.
4.13.1 High Voltage Supply Transformer T1
Transformer T1 is a three phase transformer with secondary
windings providing six AC phases to a 12-phase full wave
rectifier (also see the paragraphs below on the 12 phase supply
and rectifier assembly). The primary windings are tapped to
allow operation with a range of input voltages; refer to Section
2, Installation, for information on correct primary connections.
T1’s primary windings are also used as auto-transformers to
provide correct voltages for blower B1, and Section 2 also
provides information on blower connections.
4.13.2 High Voltage Supply Primary Power Contac-
tors
Primary power for the High Voltage supply is applied through
two contactors:
1. Step-Start Contactor K1, and
2. High Voltage Supply Contactor K2.
Auxiliary contacts on both contactors provide logic signals to
the turn-on/turn-off circuits on the Controller Board and also
operate the Power Supply Discharge board to discharge the high
voltage supply whenever both contactors are de-energized.
4.13.3 High Voltage Step-Start (K1, K2, R31-R33)
When the high voltage supply is first turned on, step-start contactor K1 is energized by turn-on/turn-off logic on Controller
board A38, and AC power is supplied to transformer T1 through
three low-resistance high wattage resistors (R31, R32 and R33).
The series resistance limits surge current as power supply capacitors charge. When K1 energizes, an auxiliary contact also
closes and provides a +22 volt “K1 has closed” logic signal to
turn-on/turn-off logic on Controller board A38.
After a little more than one second, the turn-on/turn-off logic
energizes contactor K2. Heavy contacts on K2 apply primary
power directly to transformer T1, completing the step-start sequence. An auxiliary contact provides a +22 volt “K2 has closed”
logic signal to the turn-on/turn-off logic. About half a second
later, step-start contactor K1 is de-energized.
An auxiliary contact on K2 also supplies +30 volts, the supply
voltage for Binary Steps 11 and 12.
4.13.4 12 Phase Supply and Rectifier Assembly
A 12-phase rectifier assembly provide a DC output with a small
ripple component at 12 times the power line frequency, that is,
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-17
at either 600 Hz or 720 Hz. The high ripple frequency reduces
the supply filtering required. A center tap on the transformer
secondary winding provides a half-voltage output (+115 volts).
(monostable multivibrator) “timer” in the control circuit prevents the transmitter from being turned on again for about 2.5
seconds after turn-off.
Transformer T1’s secondary windings are wound to provide six
output phases, 60 degrees apart. This is done by constructing the
windings so that a large voltage, phased the same as one incoming phase, is added to a small voltage which either leads or lags
the larger voltage by 120 degrees. For each secondary winding,
two voltages then add vectorially to give an output that either
leads or lags an incoming phase. The six secondary windings
then provide a six-phase input to the rectifiers and full-wave
rectification makes up the 12 phase supply.
A 250 ohm resistor provides a discharge path through K1-K2
contacts if the FETs failed to fire or if the 10 ohm resistors fail,
although the high wattage resistor used in the discharge circuit
makes this very unlikely.
4.13.4.1 Supply Filtering
The +115 volt supply uses a small series inductance, L3, and
three parallel filter capacitors. Each capacitor has a bleeder
resistor across its terminals to discharge the capacitor in the
unlikely event that other discharge mechanisms fail. Additional
smaller filter capacitors on the Binary Combiner/Motherboard
(A18), close to the RF amplifier modules, bypass high frequency
noise and ripple components to ground.
The +230 volt supply has six outputs, each with a separate fuse
and filter capacitor. Again, smaller electrolytic capacitors on the
Combiner/Motherboards (A18, A19, and A20) bypass high frequency components to ground. All these electrolytic capacitors
also have bleeder resistors across their terminals.
4.13.4.2 Fuses in DC Lines
Fuses A24F2 through A24F8 in the unfiltered +230 volt line
distribute +230 volts to supply filter sections and groups of PA
RF amplifier modules, and provide protection in case of short
circuits or other serious malfunctions in the supply’s load without shutting down the entire power amplifier. One additional
fuse, A24F1, is located in the filtered +115 volt supply line to
the Binary Combiner/Motherboard. All fuses are mounted on
Fuse Board A24.
A series diode-resistor circuit is connected in parallel with each
fuse. If the fuse opens, the diode-resistor circuits allow the filter
capacitors to discharge through the Power Supply Discharge
board, and through mechanical shorting switches if the interlocked doors are opened. When the supply is operating, the
diodes across any open fuses will be reverse biased so that no
current is supplied to components after the fuse.
4.13.5.1 Mechanical Shorting Switches, S9 AND S10
When either interlocked door is opened, a heavy mechanical
shorting switch in parallel with the Power Supply Discharge
circuit provides a direct path from the +230VDC supply to
ground. One interlocked door is the power supply compartment
front door, and the other is the PA module access door at the back
of the front non-interlocked compartment.
4.13.5.2 +115VDC and +230VDC Supply Filter Capacitor
Discharge Paths
Referring to the overall schematic diagram(s), note that fuses
A24F1 through A24F8 are between the Power Supply Discharge
circuit and filter capacitors. Normally, capacitors discharge
through the fuse, but if any fuse opens a diode and series
resistance in parallel with the fuse still allow capacitors to
discharge when the discharge circuit operates.
The +115VDC supply output discharges through rectifier diodes
CR1 through CR6. The +115VDC supply filter capacitors discharge to the rectifier assembly through A24F1, filter inductor
L3, and A24F8 (or through the diode and resistor networks in
parallel with the fuses if one or both fuses open).
4.14 Supply Current Meter, M2
The negative side of the high voltage supply (main power
supply) returns to ground through the supply current meter
circuit. The supply current meter reads all high voltage supply
current, including RF driver current and PA current.
The Supply Current Meter is shown in the lower left corner of
Sheet 1 of the DX-10 overall schematic diagram. The negative
side of the supply goes to ground through a 250 ampere current
meter shunt SH1, which is located in the power supply compartment. The Supply Current meter (M1) is located on the transmitter’s front panel, and is connected across the shunt.
4.13.5 Power Supply Discharge Circuit
The Power Supply Discharge board FETs discharge the supply
through a low resistance whenever primary power contactors K1
and K2 both de-energize. The FETs are triggered by the supply
voltage through K1 and K2 auxiliary contacts and a resistor.
The interconnecting wires between shunt SH1 and supply current meter M1 form part of the total current metering circuit
resistance. DO NOT CHANGE THE SUPPLY CURRENT METER’S INTERCONNECTING WIRES, AS METER CALIBRATION WILL BE AFFECTED.
When K1 and K2 are both de-energized, the +230VDC unfiltered voltage is applied to the gate of the FETs (Q1, Q4) through
resistors R6 and R12. This voltage triggers the FETs so the
unfiltered +230VDC line is grounded through 10 ohm resistors.
The FETs gate voltage comes directly from the +230VDC supply
so the FETs remain ON until the supply voltage drops to only a
few volts. Even with the small resistance used, complete discharge requires up to a second or more; for this reason, a one-shot
Current meter shunt SH1 is a four-terminal 50-millivolt shunt.
The 250 ampere terminals are at the ends of the shunt, and
another pair of terminals go to the meter and overload circuit.
With this four-terminal configuration, any contact resistance at
the high-current connection points is not part of the meter circuit
and will not affect meter calibration.
4-18
The voltage across the shunt, which is proportional to supply
current, also goes to the supply current overload circuit on LED
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
board A32, through the switch board/meter panel. The current
overload circuit provides a remote supply current metering output as well. (Refer to Section Q, LED Board, for a description
of the supply current overload circuit. The overload circuit is
shown on Sheet 2 of the LED Board schematic.
4.15.1.3 High Voltage “Overvoltage” Sample
Resistors R19, R20, and R21 form a voltage divider. The voltage
sample from the divider goes to a Power Supply Overvoltage
circuit on Controller Board A38. The Overvoltage circuit is
shown on the Controller schematic diagram.
4.15.1.4 “Analog Input” Sample
4.15 Fuse Board, A24
The high voltage supply fuses and diode-resistor back-up discharge networks are located on Fuse Board A24. Four high
voltage supply sample circuits, and resistors R25-R26 which are
part of a Driver Supply Regulator circuit, are also located on the
fuse board.
Resistors R25-R26 from the +230VDC supply are collector load
resistors for a Driver Supply Regulator stage (refer to Section E,
Driver Supply Regulator, for a circuit description). The connection to the driver supply regulator is made at terminal E14 on the
fuse board.
4.15.1 Voltage Sample Circuits on the Fuse Board
Fuse Board A24 includes four voltage sample circuits, as follows:
a. Power Supply Protection: Sample of AC ripple, for Power
Supply Protection circuit on LED Board A32.
b. “Voltmeter” Sample: Provides a sample of supply voltage
for both front panel and remote metering. This sample
passes through the LED Board to a voltage follower on
Controller Board A38.
c. Voltage “Overload” Sample: Provides a sample of supply
voltage for the “Overvoltage” circuit on LED Board A32.
d. “Analog Input”: This is a supply voltage sample, for the
supply voltage compensation circuits on Analog Input
Board A35 and to the “Envelope Error” detection circuit
on LED Board A38.
4.15.1.1 “Power Supply Protection” Sample
This is an AC sample of the supply’s ripple, for the power supply
protection circuit on the LED board. R14-R15 form a DC and
AC voltage divider. Capacitor C1 blocks DC, and C1-C2 form
an AC voltage divider. Fuse F9 provides circuit protection, and
CR9 is a bipolar 18 volt Transzorb which provides overvoltage
or transient protection. (Refer to Schematic of LED Board and
to Section Q for a description of the Power Supply Protection
circuit.)
Resistors R22, R23, and R24 form a voltage divider. On Analog
Input board A35, the output voltage sample is used to make small
adjustments to modulation to compensate for RF power output
changes resulting from supply voltage changes. The sample also
goes from the Analog Input board to the “Envelope Error”
detection circuit on LED Board A32.
4.15.1.5 Power Supply Sample
The “Power Supply Sample” circuit, A35U12B and A35U10, is
described in Section J, Analog Input Board, and is shown on the
Analog Input Board schematic diagram. The Envelope Error
circuit is shown on the LED Board Schematic Diagram. A circuit
description is also included in Section Q.
4.16 Blower B1, Air Flow Sensing Unit
S7 and Temperature Actuated
Switch
4.16.1 Blower
The blower assembly provides cooling air for the transmitter,
primarily for the PA modules. The blower and fan assembly is
mounted at the bottom of the wall between the center rear RF
combiner/motherboard compartment and the output network
compartment. It provides positive pressure in the center rear
compartment, and most air flow is through the PA modules and
out the top of the transmitter.
The blower uses a three-phase motor. High Voltage Supply
(Main Power Supply) transformer T1 is used as a three phase
autotransformer to supply the correct voltage for the blower
motor. Refer to the paragraphs on “Electrical Installation” in
Section 2, Installation, for information on correct voltage taps
and motor junction box connections.
The blower motor is protected by fuses F7, F8, and F9, located
on the outside wall of the power supply compartment. If these
fuses open and the blower stops, the air flow sensing switch will
open and an “Air Fault” will turn the high voltage supply OFF.
4.15.1.2 “Voltmeter” Sample
4.16.1.1 Air Flow Sensing Unit S7 and Temperature Actuated Switch
Resistors R16, R17, and R18 form a voltage divider. A voltage
follower (gain = 1) on Controller Board A38 provides outputs to
the front panel multimeter (part of Switch Board/Meter Panel
A031) and to the External Interface board (A28) for remote
supply voltage metering.
The DX-10 transmitter has redundant cooling sensors. The first
cooling sensor is a pressure actuated Air Switch, S7, which is
designed to drop out if the blower motor fails, or if the motor is
rotating in the wrong direction.
The supply voltmeter sample passes through LED board A32.
The voltage follower, A38U56C, is shown on the Controller
schematic diagram.
03/16/2009
The Air Flow Sensing Unit is a differential pressure switch,
located in the center rear compartment, at the top of the left side
wall (as viewed from the rear of the transmitter).
The “high pressure” side of the air switch is open to the center
compartment. The “low pressure” side is at ambient pressure of
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-19
the Output Network compartment. A plastic sample tube goes
from the switch to the Output Network. When sufficient air
pressure across the blower is available, the switch closes and
supplies +8 volts to the logic input of the “Air Flow Fault” circuit
on LED Board A32.
Refer to Section Q, LED Board, for a description of the “Air
Flow Fault” circuit. The circuit is shown on sheet 1 of the LED
Board schematic diagram. Adjustment of the Air Flow sensing
unit (S7) is described in Section 5, Maintenance.
The second cooling sensor is a temperature actuated switch
located on the heat sink of the RF amplifier module which is
located in the Step 1 location (with the 1A & 1B LED indicators).
This sensor will trip the transmitter if an over temperature
condition exists in the RF Amplifier column. This over temperature condition could be caused by an excessively dirty inlet air
filter, or possible an obstruction of the exhaust air port at the top
of the transmitter. If the Step 1 module should fail, the temperature sensor should be transferred to a functioning amplifier
module and the new assembly should installed in the Step 1
location.
4.18.2 Other Voltage Regulators
A number of printed circuit boards contain integrated circuit
voltage regulators. Refer to Section M, DC Regulator, for a
description of +5 volt and +15 volt regulators. In addition to the
DC Regulator, the following printed circuit boards contain onboard integrated circuit voltage regulators:
a. Oscillator, A17
b. Output Monitor, A27
c. External Interface, A28 (3-terminal regulators)
d. Analog to Digital Converter A34
e. Analog Input A35
f. Controller A38
LED Board A32 operates from regulated voltages from the
Controller Board (A38), and the Modulation Encoder A36 operates from regulated voltages from DC Regulator A30.
4.19 RF Circuit Descriptions, For RF Cir-
cuits Not on Printed Circuit Boards
4.17 Interlocks and Interlock Relays
Interlocks and interlock relays turn the transmitter OFF if either
interlocked door is opened. Interlocked doors on the DX-10 are
the front door of the power supply compartment, and the RF
amplifier module access door at the back of the center front
non-interlocked compartment.
Some additional Interlock circuits are located on the DC Regulator board A30, and interlock logic is located on Controller
Board A38. For a description of interlock circuits and logic, refer
to section P, Controller Board. For additional schematic diagrams, also refer to the DC Regulator Schematic diagram, DC
Regulator and to sheet 1 of the Controller schematic diagram.
Figure P-8, “Simplified Diagram, Interlock Status Logic,” also
shows interlock circuits.
4.19.1 RF Driver Combiner Description
The RF Driver Combiner uses ferrite toroids mounted on the RF
Driver Combiner/Motherboard as combiner transformer primary
windings. A copper rod going vertically through the toroids is a
secondary winding. The combiner output goes to the PA RF
Drive Splitter, A15. Inductor L2, located above the RF amplifier
module access door, is an impedance matching adjustment (this
is a MAINTENANCE adjustment, not a routine tuning adjustment) Frequency-determined taps on the Driver Combiner toroidal transformer primaries provide coarse adjustment.
Refer to Section D, Driver Combiner/Motherboard, for additional description; the driver combiner is shown on the Driver
Combiner/Motherboard schematic diagram. Section 5, Maintenance, describes tuning adjustments and the Frequency Determined components charts in Section 9 indicate proper tap and
jumper plug settings.
4.19.2 Grounding Block for the Driver and output
4.18 Voltage Regulators
4.18.1 Voltage Regulator Assemblies
There are two voltage regulator assemblies in the DX-10:
a. Driver Supply Regulator A22, which provides regulated
voltages for one section of the RF Driver and is described
in Section E, Driver Supply Regulator. (Also refer to
Section D, Driver Combiner/Motherboard, for use of the
regulated voltage).
b. DC Regulator A30, which supplies regulated +5 V and
Modulated B-voltages to the Modulation Encoder. HV
Supply contactor driver circuits and some interlock circuits are also located on the DC Regulator board. The DC
Regulator is described in Section M, DC Regulator.
4-20
Combiner Secondary
The Driver Combiner secondary is a heavy copper rod. Physically, this rod is an extension of the PA Output Combiner rod,
but the rod is grounded by a copper grounding block on the
Driver Combiner/Motherboard. (Figure 1-10, in Section 1 of this
Technical Manual, shows the Driver Combiner and part of the
PA Output Combiner, with the Combiner Cover removed.) The
Combiner Cover slides over the grounding block and is secured
to the block with five screws. THE TRANSMITTER MUST
NOT BE OPERATED UNLESS THE COMBINER COVER IS
IN PLACE AND ALL SCREWS HOLDING THE COVER TO
THE GROUNDING BLOCK ARE INSTALLED AND PROPERLY TIGHTENED. THE COMBINER COVER CARRIES
MOST OF THE COMBINER SECONDARY CURRENTS.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
The combiner rod ABOVE the grounding block is the RF Driver
combiner secondary, and the combiner rod BELOW the grounding block is the PA Combiner secondary. There are two toroids,
T8 and T9, physically mounted on the driver combiner/motherboard (A14) but electrically coupled to the grounded end of the
PA combiner secondary (the combiner rod). T9 is the Neutralizing transformer, and T8 is a PA combiner current sample for the
Bandpass Filter VSWR phase detector on Output Monitor board
A28.
4.19.3 RF Drive Splitter, A15
The RF Drive Splitter’s input is the signal from the RF Driver.
The splitter provides 96 outputs, one for each half-quad for each
of the 48 power amplifier modules. An additional connector
(J13) on the splitter assembly provides three RF sample signals
to other parts of the transmitter, as follows:
a. To Driver DC Supply Controller A22: An RF sample for
the RF drive Automatic Gain Control (AGC) loop.
b. To Analog to Digital Converter A34: A synchronizing
signal for the A/D Conversion process.
c. To LED Board A32: An RF drive sample, for Overdrive
and Under drive Fault sensor circuits and for “Relative RF
Drive” Metering.
The RF splitter assembly is mounted at the top of the combiner/motherboard compartment. The ungrounded end of the
Driver Combiner’s secondary rod is connected directly to the
splitter as an input.
The splitter’s RF drive outputs to the PA are at twelve 20-pin
connectors (J1 through J12). Each connector provides connections for eight coaxial cables; the eight cables from each connector form a cable bundle which goes to an input connector on a
PA Combiner/Motherboard. There are then twelve bundles of
eight coaxial cables; each bundle goes from an output connector
on the RF drive splitter to an input connector on one of the three
PA Combiner/Motherboards.
4.19.4 RF Drive Cables
The RF drive splitter outputs, at connectors J1 through J12, are
very low impedance, and the separate RF drive cables to each
PA module input provide additional isolation so that a fault at
one module input will have little or no effect on any other RF
drive signals.
All RF drive cables are the same length, so that all PA RF
amplifier inputs are in phase. Cables are in twelve groups of
eight, with each group of cables going from one RF drive splitter
output connector to one of 12 RF drive input connectors on the
PA combiner/motherboards.
4.19.5 RF Power Amplifier Description
The RF power amplifier is made up of 48 plug-in RF amplifier
modules (A44 through A91), which plug in to three RF Combiner/Motherboards (Main Combiner/Motherboards A19 and
A20, and Binary Combiner/Motherboard A19). In addition to
edge connectors for 16 plug-in RF amplifier modules, each
Combiner/Motherboard provides input connectors and distribu-
03/16/2009
tion for DC power, RF drive, and encoded audio signals, decoupling filters for DC power supply lines, and tapped inductors in
parallel with each combiner primary toroid. The Output Combiner primary windings are wound on ferrite toroids which are
mounted on the Combiner/Motherboards so that the copper rod
combiner secondary passes through all the toroids.
The plug-in RF amplifier modules include 42 “Big Step” modules and six “Binary Step” modules. Sheet 2 of the DX-10
Overall Schematic Diagram identifies step numbers and module
numbers. PA Modules are also identified by step number on the
interlocked module access door. (Big Step and Binary Step
modules have been described in the paragraphs on “DX-10
Power Amplifier Section Principles” earlier in this section.)
Each RF amplifier module has two LED “fault” indicators,
visible through openings in the access door. If a module fault
causes a fuse on the module to open, the “fault” indicator for that
fuse illuminates.
Refer to the following sections for additional information on the
Power Amplifier, including schematic diagrams:
a. Section A, RF Amplifier Module.
b. Section G, RF Combiner/Motherboards: Binary (A18) and
Main (A19-A20).
c. The description of Quantized Amplitude Modulation in
this section includes paragraphs on “Amplitude Modulation in the DX-10" and ”DX-10 Power Amplifier Section
Principles."
d. Sheet 2 of the DX-10 Overall Schematic Diagram shows
DC power connections to the power amplifier section,
through the Combiner/Motherboards.
e. Figures 1-10 and 1-11 are close-up views of the back side
of PA Combiner/Motherboards and the Output Combiner.
Recall that the “steps” in the DX-10 modulated RF output are
equal VOLTAGE steps, not equal power steps. If the RF load,
transmitter tuning, and supply voltage remain the same, the RF
output VOLTAGE from each module remains the same no
matter how many other modules are on. The power output from
each amplifier module changes, however, depending on the total
number of amplifier modules (“steps”) that are switched on. (All
module outputs, at the combiner secondary, are in series, and
output current from all modules must be equal. As transmitter
output changes, output current changes; because RF voltage
from each module is constant, the module’s output power varies
depending on the number of modules that are turned ON.)
In the DX-10 power amplifier, then, think in terms of RF
VOLTAGE from each module. Big Steps all have equal RF
output VOLTAGES, and Binary Steps are a 1/2 voltage step, a
1/4 voltage step, and so on.
All Big Steps have the same number of turns on their combiner
primary windings. Binary Steps use different turns ratios, lower
supply voltages, or both to get fractional voltage outputs. This
can be seen in Figure 1-10, which shows a section of the output
combiner with the cover removed.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-21
4.19.6 RF Output Combiner Description
The RF output combiner has 48 inputs, one from each of the RF
power amplifier stages. Its output is the total RF output of the
transmitter. The combiner’s output impedance is low, about 4
ohms, so that at 10 kilowatts the current is about 50 amperes.
The combiner secondary and bandpass filter/output network use
heavy conductors to minimize (I*2R) losses.
Physically, the output combiner consists of a heavy straight
copper rod, which passes through the 48 ferrite toroids mounted
on the three RF combiner/motherboards. The winding around
each ferrite toroid is a combiner primary winding, and a voltage
is induced in the section of the combiner secondary rod which
passes through the toroid. The total RF voltage at the combiner
output is just the sum of all the RF voltages induced in sections
of the combiner rod.
The copper rod is made in sections, which are bolted together.
Using sections rather than one continuous rod facilitates removal
of combiner/motherboards if required. The combiner is covered
with a long U-shaped aluminum cover which also conducts most
of the RF output current from the combiner rod’s ground point
to the cabinet.
The combiner’s OUTPUT is at the BOTTOM, and is connected
to a conductor which passes through the compartment wall to the
output network compartment. The other end of the PA combiner
is grounded, using a copper grounding block (already described
in the driver combiner/motherboard description in this section).
The combiner rod extends above the grounding block, where it
becomes the secondary for the RF driver combiner (already
described in the driver combiner/motherboard description in this
section).
4.19.6.1 RF Samples for the Output Combiner
The upper end of the combiner rod, near the grounding block on
the Driver Combiner/Motherboard, also passes through two
additional toroids, A14T8 and A14T9 (both A14T8 and A14T9
are mounted on the Driver Combiner/Motherboard).
A14T8 is used for neutralization and A14T9 provides a combiner
current sample for the “Bandpass Filter VSWR” phase detector
on the output monitor board. Driver Feed through neutralization
is described in Section G, RF Driver Combiner/Motherboard.
Two more RF samples are taken from the combiner’s output, by
RF sample inductors in the output network compartment. One
sample, from T101, goes to the “Oscillator Sync” circuit on
Oscillator board A17, and the other, from T102, goes to the
Sample Sync circuit on A/D Converter board A34.
T101, the “Oscillator Sync” sample coil, is a small ferrite core
coil, mounted on the output network compartment side wall at
the point where the combiner output enters the compartment and
inductively coupled to the RF conductor.
T102, the A/D Conversion synchronizing signal sample, is also
a small inductor mounted near T101 (see the previous paragraph).
For additional information on circuits using the three samples,
refer to the following:
4-22
a. Bandpass Filter VSWR circuit phase detector (using current sample from A14T9): See Section H, Output Monitor
Board. A14T9 is shown on the RF Driver Combiner/Motherboard schematic diagram and as a “Combiner Current
Sample” on sheet 1 of the DX-10 Overall Schematic
Diagram.
b. “Oscillator Sync” sample, from T101: Refer to Section A,
Oscillator (Oscillator Sync circuit description). Additional
information on synchronizing RF drive and output network ringing currents during a VSWR shut-down is given
in Section C, RF Amplifier Modules.
c. A/D Converter sync circuit (using the sample from T101):
Refer to Section K, Analog to Digital Converter.
The “Oscillator Sync” sample is used to synchronize the power
amplifier modules’ RF drive phase with the phase of the combiner “ringing currents” when a VSWR fault shuts the PA’s off.
When the PA is shut off quickly, these ringing currents are
present in the combiner as the stored energy in the output
network dissipates. The “Oscillator sync” function protects PA
power MOSFET’s during VSWR shut-down. (For additional
information, refer to Section A, Oscillator, and Section C, RF
Amplifier Modules).
4.19.7 Bandpass Filter (Output Network) Description
The bandpass filter/output network is both a filter and an impedance matching network. The combiner output impedance is low
(about 4 ohms) and is matched to the 50 ohm point where the
output sample board is located. This impedance transformation
is fixed, and is set during bandpass filter tuning and adjustment
at the factory or after a frequency change. A 50-ohm load is then
required at the bandpass filter’s output for proper transmitter
operation.
The bandpass filter also smooths the small steps that are present
in the PA’s output; the small steps result from sidebands outside
the audio frequency range which are attenuated in the filter. Any
other harmonic and spurious signals in the RF power amplifier
section output are also attenuated by the bandpass filter.
4.19.7.1 There are no Operator Tuning Adjustments for the
Bandpass Filter/Output Network
The bandpass filter is located in the Output Network compartment of the transmitter, above the lower shelf. (The Tee Matcher
is located on the upper shelf).
4.19.8 Bandpass Filter/Output Network Circuit De-
scription
L101 and C101-C102 form a series resonant section, and L102C103 is a parallel resonant circuit with a tapped inductor which
also provides impedance matching. One tap on L102 resonates
the parallel circuit, and the other two taps set both circuit Q and
impedance matching. The coil tap position on L101 sets Q of the
series resonant section.
Section 5, Maintenance describes proper tuning of the bandpass
filter. Again, TUNING OF THE BANDPASS FILTER
SHOULD NOT BE ATTEMPTED WITHOUT PROPER TEST
EQUIPMENT.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
4.19.9 Output Sample/Output Monitor
Refer to Section H, Output Sample and Output Monitor, for
descriptions of these boards.
4.19.10 TEE Matcher: “Tune” and “Load” Controls
DX-10 Output Network tuning is fixed, and requires a 50 ohm
resistive load for optimum operation. The Tee Matcher provides
convenient tuning to match loads within a 1.5:1 VSWR circle at
the carrier frequency. The Tee Matcher also provides additional
attenuation for harmonic frequencies.
Adjustable impedance matching is important because many
antenna systems don’t present exactly a 50 ohm load, and antenna system (common point) impedance may change somewhat
from time to time. There may also be a difference between a
dummy load and an antenna system. (Refer to the specifications
in Section 1 of this Technical Manual for additional information
on the range of loads which can be matched).
4.19.10.1 Adjusting “Tuning” and “Loading” Controls
The matching network has two matching adjustments, both
available from the front of the transmitter. One is labeled
“TUNE” and the other is labeled “LOAD.” These adjustments
must be made to obtain a minimum reading in the “DETECTOR
NULL (ANTENNA)” multimeter reading (this will also be
minimum REFLECTED POWER).
Tuning and Loading controls on the DX-10 are adjusted for an
impedance match at the Output Sample point. The Detector
Null (Antenna) meter indication is a more sensitive indication of
this impedance match than the Reflected Power reading. Do not
use Tuning and Loading controls on the DX-10 to adjust PA
voltage or current.
4.19.10.2 To adjust Tuning and Loading:
1. Switch the front panel Multimeter selector switch to the
“DETECTOR NULL (ANTENNA)” position.
2. While watching the multimeter, alternately adjust the
Tuning and Loading controls for a minimum reading
on the meter. (The REFLECTED POWER indication
03/16/2009
on the power meter will also go to a minimum, but is a
less sensitive tuning indication).
3. When TUNING and LOADING controls are properly
adjusted, the DETECTOR NULL (ANTENNA) reading should be at or near zero, and the REFLECTED
POWER should read zero.
Refer to 817-1280-101, DX-10 Bandpass Network Setup chart
for the impedance values desired if any adjustment is necessary.
4.19.11 Circuit Description
The Tee network series legs (L103 and L104) are inductive. The
shunt leg (L105 and C104) is series resonant at the third harmonic frequency, and capacitive at the carrier frequency, and
thus forms a third harmonic trap which reduces any third harmonic output to a very low level. L103 and L104 are variable
inductors, which are adjustable from the front panel. These two
controls are labeled “Tuning” and “Loading.”
Tee Matcher components are located in the top shelf in the output
network compartment.
4.19.12 Modulation Monitor Sample Coil (L107)
The modulation monitor sample coil is connected between the
transmitter’s power output and ground. An adjustable tap on the
coil sets the modulation monitor sample voltage at LOW power.
After the LOW power sample level has been set, MEDIUM and
HIGH power mod monitor sample levels are adjusted, using
controls on the Output Monitor board, so that the RF level at the
modulation monitor input is the same for all three power levels.
(A procedure for Modulation Monitor Sample level adjustment
is included in Section 2, Installation.)
4.19.13 Spark Gap, E101
A spark gap at the transmitter’s output protects the transmitter
against high transient voltages caused by lightning or electrostatic discharge. (This does NOT substitute for proper DC
grounding chokes, ball gaps, and other protection at the towers.)
888-2247-006
WARNING: Disconnect primary power prior to servicing.
4-23
4-24
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section V
Maintenance/Alignments
5.1 Introduction
This section provides general system preventive maintenance
information, board replacement and alignment procedures and a
transmitter frequency change procedure.
5.2 Maintenance
The importance of keeping station performance records cannot
be overemphasized. Separate logbooks should be maintained for
operation and maintenance. These records can provide data for
predicting potential problem areas and analyzing equipment
malfunctions.
5.2.1 Maintenance Logbook
The maintenance logbook should contain a complete description
of all maintenance activities required to keep the equipment in
operational status.
The following is a list of maintenance information to be recorded
and analyzed to provide a data base for a failure reporting
system:
5.2.1.1 Discrepancy
Describe the nature of the malfunction including all observable
symptoms and performance characteristics.
5.2.1.2 Time/Date
Time of day and date discrepancy occurred.
5.2.1.3 Corrective Action
Describe the repair procedure used to correct the malfunction.
5.2.1.4 Defective Parts(s)
List all parts and components replaced or repaired and include
the following details:
a.
b.
c.
d.
e.
Time in Use
Part Number
Schematic Number
Assembly Number
Reference Designator
Inspection is the most important preventive maintenance operation because it determines the necessity for the others. Become
thoroughly acquainted with normal operating conditions in order
to readily recognize and identify abnormal conditions. Inspect
for the following:
1. Overheating, which is indicated by discoloration, bulging of parts, and peculiar odors.
2. Oxidation.
3. Dirt, corrosion, rust, mildew, and fungus growth.
• Feel
By checking for overheating, lack of proper ventilation or other
defects can be detected and corrected before serious trouble
occurs. Become familiar with operating temperatures in order to
recognize deviations from the normal range.
• Tighten
Tighten loose screws, bolts, and nuts. Do not overtighten.
• Clean
Clean parts only when inspection shows that cleaning is required
and only use approved cleaning solvent.
• Adjust
Make adjustments only when inspection shows that they are
necessary to maintain normal operation.
• Paint
Paint surfaces with the original type of paint (using prime coat
if necessary) whenever inspection shows rust or broken paint
film.
5.2.3 Maintenance Of Components
The following paragraphs provide information necessary for the
maintenance of components.
5.2.3.1 Transistors and Integrated Circuits
Preventive maintenance of transistors and integrated circuits is
accomplished by performing the following steps:
CAUTION
USE CARE TO AVOID THE BUILDUP OF STATIC ELECTRICITY
WHEN WORKING AROUND INTEGRATED CIRCUITS.
5.2.1.5 System Elapse Time
Total time on equipment
5.2.1.6 Name of Repairman
Person who actually made the repair
5.2.1.7 Station Engineer
Indicates Chief Engineer noted and approved the repair of the
equipment
5.2.2 Preventive Maintenance
Preventive maintenance is a systematic series of operations
performed periodically on equipment and consists of six operations: inspecting, feeling, tightening, cleaning, adjusting, and
painting.
a. Inspect the surrounding area for dirt. Accumulations could
form leakage paths.
b. Use a vacuum and a parts brush to remove dust from the
area.
c. Examine all transistors for loose connections or corrosion.
Tighten the transistor mounting hardware to no more than
5 inch-pounds. Overtightening the transistor hardware will
cause the insulators to short. Torque specification for
transistor mounting hardware is 5 inch-pounds.
5.2.3.2 Capacitors
Preventive maintenance of capacitors is accomplished by performing the following steps:
• Inspect
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-1
a. Examine all capacitor terminals for loose connections or
corrosion.
b. Ensure that component mountings are tight. Do not overtighten capacitor mounting straps as excessive pressure
could cause internal shorting of the capacitors.
c. Examine the body of each capacitor for swelling, discoloration, or other evidence of breakdown.
d. Use standard practices to repair poor solder connections
with a low-wattage soldering iron.
e. Clean cases and bodies of all capacitors.
f. Inspect bleeder resistors when inspecting electrolytic capacitors.
5.2.3.3 Fixed Resistors
Preventive maintenance of fixed resistors is accomplished by
performing the following steps:
a. When inspecting a chassis, printed-circuit board, or discrete component assembly, examine resistors for dirt or
signs of overheating. Discolored, cracked, or chipped
components indicate a possible overload.
b. When replacing a resistor, ensure that the replacement
value agrees with the schematic diagram and parts list.
c. Clean dirty resistors with a small brush.
5.2.3.4 Variable Resistors
Preventive maintenance of variable resistors is accomplished by
performing the following steps:
a. Inspect the variable resistors and tighten all loose mountings, connections, and control knob set-screws (do not
disturb knob alignment). Sliding taps on adjustable resistors should be snug, but not excessively tight. Overtightening can damage the resistor.
b. Clean dirty resistors with a small brush.
c. When dirt is difficult to remove, clean with a lint-free cloth
moistened with an approved cleaning solvent.
5.2.3.5 Fuses
a. Inspect switch for defective mechanical action or looseness of mounting and connections.
b. Examine cases for chips or cracks. Do not disassemble
switches.
c. Check contacts for pitting, corrosion, or wear.
d. Operate the switches to determine if they move freely and
are positive in action.
e. Be sure to include an inspection of the power supply
discharge switches S9, S10 and S12 located in the interlocked RF Amplifier and Driver Compartments.
5.2.3.7 Indicators and Front Panel Switches
Preventive maintenance of indicator lamps and control switches
is accomplished by performing the following steps:
a. To remove an indicator bulb (LOW, MED, HIGH, RAISE
or LOWER) pull out on the indicator button. The indicator
lamp may then be removed. When re-installing the button,
care must be taken to avoid disrupting normal operation.
b. Replacement of a front panel switch requires removal of
the Switch Board behind the meter panel.
5.2.3.8 Printed Circuit Boards
Preventive maintenance of printed circuit boards is accomplished by performing the following steps:
a. Inspect the printed circuit boards for cracks or breaks.
b. Inspect the wiring for open circuits or raised foil.
c. Check components for breakage or discoloration due to
overheating.
d. Clean off dust and dirt with a clean, dry lint-free cloth.
e. Use standard practices to repair poor solder connections
with a 40 Watt soldering iron.
5.2.3.9 Air System
a. The air filters should be routinely washed with soap and
water. Intervals between cleaning will depend on the environment.
b. Replace filter when it shows signs of deterioration.
Preventive maintenance is accomplished by performing the following steps:
CAUTION
USE ONLY AN EXACT REPLACEMENT FUSE. FUSES OF THE
SAME SIZE AND/OR RATING FROM A DIFFERENT MANUFACTURER MAY NOT FULFILL THE REQUIREMENT FOR EXACT
REPLACEMENT.
a. When a fuse blows, determine the cause before installing
a replacement.
b. Inspect fuse caps and mounts for charring and corrosion.
c. Remove dirt with a small brush.
d. If necessary, tighten fuse clips and connections to the clips.
Fuse clip tension may be increased by pressing the clip
sides closer together.
5.3.1 Replacing Boards and Components on Boards
When replacing some boards in the DX-10, preset switch settings or jumper plug positions and some boards require adjustments that must be preset or adjustments and/or measurements
that must be made after replacing the board (outlined later in this
chapter).
5.4 Boards which can be Replaced with
No Adjustments
5.2.3.6 Switches
Preventive maintenance of switches is accomplished by performing the following steps:
5-2
5.3 Corrective Maintenance
The following boards may be replaced, or components on them
can be replaced, without making any adjustments, measurements, or preset switch or jumper plug settings:
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
a.
b.
c.
d.
e.
f.
SWITCH BOARD/METER PANEL A31 *
EXTERNAL INTERFACE A28 *
RF MULTIMETER A23 *
MAIN COMBINER MOTHERBOARDS A19 and A20
FUSE BOARD A24
OUTPUT SAMPLE A26 (Note: Component changes may
require nulling of Output Monitor board A27.)
g. DRIVE SPLITTER A15
h. POWER DISTRIBUTION A39
i. * NOTE: Resistor changes may require recalibration of
remote control readings.
5.5 Boards which Require Preset Switch
Settings or Jumper Plug Positions
The following boards have no adjustments, but may have jumpers or switches that can be preset to the settings on the board to
be replaced. These boards can also be partially checked before
application of the high voltage. The list of these boards and their
replacement procedure follows.
a.
b.
c.
d.
e.
f.
g.
MODULATION ENCODER A36
CONTROLLER A38
BUFFER AMPLIFIER A16
PREDRIVER A10
RF AMPLIFIERS
DRIVER COMBINER/MOTHERBOARD A14
BINARY COMBINER/MOTHERBOARD A18
5.5.1 Modulation Encoder A36
When replacing the Modulation Encoder, make sure that the
binary output switches S1 sections 1 through 8 are all turned on.
Make sure the gold jumpers are in place for the Big step encoder
signals 1 through 42 (P-1 through P-6) A FlexPatch™ jumper
should be in place from P-15 to P-6 terminal 6. This is the right
hand hole on the pair of holes for step 43. Extra FlexPatch™
jumpers can be installed in the holes in P-8
5.5.2 Controller A38
Once the new controller board is installed, the AC power can
now be applied to the transmitter. Check to see that the regulator
fault indicator on the board DS1 is not lit. A DC voltmeter can
now be used to ensure that the regulators are operational. Check
the following test points for the indicated voltage.
TP1 ....... +5VDC
TP2 ....... +15VDC
TP3 ....... -15VDC
NOTE
The Controller board contains a large value capacitor backup
which is discharged after two hours. Do not install the additional
battery backup BT1 through BT3 until the controller board has
been installed and power has been applied for at least 1 minute.
03/16/2009
Once the regulator voltages have been measured, ensure that the
PA turn off switch S5 is in the PA-ON position (down). The
transmitter high voltage can now be turned on and it will now be
noted that the power output of all three power levels will be zero.
Reset the transmitter output to the desired power. See the Operation Section of the manual for this procedure.
5.5.3 Buffer Amplifier A16
If the Buffer Amp is changed, it is advisable to check the drive
level to the Predriver module A10. Turn off the low voltage to
the transmitter by switching S11 OFF (lower right side of the
front non-interlocked compartment). Locate the Predriver behind the inner front door, and attach the scope to the left hand
side of CR3. Reapply the low voltage by turning S11 on. Verify
that the drive level to the Predriver is between 10Vp-p and
20Vp-p. If no signal exists check the right hand side of CR4.
Since only half of the Predriver is used at one time only the
selected half of the Predriver will have drive applied. The Predriver selection is set by the position of S1 on the Driver
Combiner Motherboard A14. Also note that the drive wave form
to the Predriver may have ringing on it and not be a clean sine
wave. See Figure 5-8.
5.5.4 Predriver A10
The Predriver module is identical to the RF Driver and RF
Amplifier modules and therefore can be interchanged if required.
No adjustments are necessary if the Predriver is changed but it
is advisable to check its output before applying the high voltage.
To do this turn off the low voltage by switching off S11, and
open the inner front door exposing the RF modules. Locate the
Driver modules A41-A43 (Section 1-3). Connect a scope to the
left hand side of CR3 on Driver section 1 (top module). Now turn
on the low voltage using S11. The drive voltage that should be
at this point should be between 15Vp-p and 25Vp-p. On the RF
Multimeter measure both the Predriver voltage and current to
verify that it is near the measurements indicated on the factory
test data sheet. It would be advisable to also measure the drive
level at right hand side of CR4 on Driver section 1 along with
these same points on the other two modules. The drive level
should be within +/- 2Vp-p of each other. Note however that the
Driver section 3B drive level (right hand side of CR4) could be
as much as +/-5Vp-p different from the others due to its being
used as a neutralization amp. Its level however should be between 15Vp-p and 25Vp-p.
NOTE
Retuning of the Predriver stage tuning control L1 is not required
when replacing the module. Changing the Predriver tuning can
affect the setting of the oscillator sync used for VSWR protection.
5.5.5 RF Amplifiers
The RF Amplifier modules are completely interchangeable, and
therefore any module can be inserted in place of a failed module
in any position. This can be done very quickly by simply turning
off the transmitter high voltage (Off button) then opening the
inner front door exposing the RF Amp modules. The module to
be replaced can be removed from its slot by pulling it out and the
replacement module can be inserted. The inner front door can
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-3
then be closed and the transmitter returned to operation. If the
low voltage is left on when a RF Amp is removed the front mimic
panel display will show a red light in the Cable Interlock block.
This fault indicator can be reset by depressing the Reset button
on the front panel. If the transmitter does not turn back on and
the Cable interlock LED remains red after resetting, check to
make sure the RF Amplifier that was replaced was fully inserted
into its slot. Some resistance is felt when the RF Amplifier is
removed or inserted in its slot.
For optimum performance from an RF Amplifier module it is
advisable to check its drive level and phasing at the time it is
installed or at a convenient maintenance period. It is possible to
get an idea if a replacement module is operating efficiently by
operating the transmitter at full power and normal modulation
for 5 minutes then shut the transmitter down. Quickly open the
inner front door and feel the heat sink of that module compared
to the ones on each side of it. If the heat sink is near the same
temperature as the ones around it, it would be safe to assume the
module is operating properly. If the module is hotter than the
others, then drive level and phasing should be checked before
operating the module further. For Drive Level and Phasing
measurement procedures see “MEASURING RF DRIVE
LEVEL,” and “MEASURING RF DRIVE PHASING,” in the
Troubleshooting section of the manual.
5.5.6 Driver Combiner/Motherboard A14
Even though the Driver Combiner/Motherboard has no variable
adjustments, there are numerous jumpers that need to be placed
in their proper location for the transmitter to operate properly.
The factory test data sheet included with each transmitter will
have a listing of the correct jumper positions when it was tested.
This can be used to preset all the jumpers on the Driver Combiner, but it would be advisable to compare the replacement
board to the board to be replaced to ensure that the jumpers are
in the correct locations. The jumpers to be checked are as
follows:
5.5.7 Binary Combiner/Motherboard A18
The Binary Combiner/Motherboard contains four jumpers used
to select the proper amplitude output of the four Binary Steps
B-7 through B-10. Set these jumpers to the same configuration
as the board to be replaced or refer to the factory test data sheet.
The procedure for replacing the Binary Combiner/Motherboard
is covered in the Maintenance section.
5.6 Printed Circuit Boards which Re-
quire Adjustments
The remaining boards in the DX-10 have adjustments which
must be checked and possibly preset before applying high voltage. Some controls may need further adjustment after applying
high voltage. The following paragraphs describe these boards
and adjustments required.
5.6.1 A to D Converter A34
The A to D Converter contains two controls, two multisection
DIP switches, and two sets of jumpers. The first step in replacing
the A to D board is to make sure that the two switches S1 and S2
are set for the same settings as the board to be replaced. S1 sets
up the A to D sample phasing and is critical to the proper
operation of the transmitter. Set jumper P10 and P11A/B to the
same settings as on the board to be replaced.
5.6.1.1 Delay Adjustment R78
J16 ....... Driver Sect.3B function select
The delay adjustment is normally set during factory testing of
the board but can be checked and adjusted if needed. Once the
new A to D board is installed apply low voltage to the transmitter
and verify that all regulators on the board are operating as
displayed by green LED’s on the Mimic Panel. Once this is done
locate the PA TURN-Off switch and move it to the PA-OFF
position. Now depress the LOW power button on the front panel
and note that the high voltage comes up but no power output is
indicated. Connect a scope to TP3 on the A to D Converter board,
connecting the scope probe ground clip to an “A” ground test
point TP19, 20, or 21. At this test point is the start of convert
pulse for the A to D Converter IC. It will be a negative going
pulse with an amplitude of 5Vp-p. Measure the width of the
positive portion of the pulse. It should be approximately 40ns. If
the pulse width is not within these ranges it can be set by
adjusting the Delay adjustment A34R78. Note that at least a
30MHz bandwidth oscilloscope is required to properly view this
pulse.
J31,J32 ...Driver tuning inductance select
5.6.1.2 Offset Adjustment R7
J15 ....... Buffer voltage select
J14 ....... Predriver tuning capacitance
J24 ........Neutralization leading/lagging select
J30 ....... Neutralization inductance select
J25-29 ....Neutralization capacitance select
J17-22 ....Driver amplitude select
J23 ......... Neutralization amplitude select
S1 .......... Predriver section select
No other tuning should be required once the new board is
installed, but instructions for selecting the proper jumper to use
are included in later parts of this Maintenance Section. Also
instructions for removal and replacement of the Driver Combiner/Motherboard are given.
5-4
The offset control is normally set during factory testing of the
board, but it can be adjusted if needed. The most significant
effect the Offset adjustment has on transmitter operation is to the
modulation tracking or in other words for a set level of audio
input, how equal is the modulation percentage at all power levels.
To initially check the setting of the Offset control, operate the
transmitter at 10kW and modulate it with a 100Hz tone at 95%
modulation. Now operate the transmitter at 1kW and measure
the percent of modulation. If it is within 1% no further adjust-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
ments are necessary to the Offset control. If the modulation
tracking is not acceptable the Offset control R7 can be adjusted
to allow the transmitter to modulate equally at all power levels.
Normally this adjustment will have the most effect on LOW
power (1kW) and therefore should be adjusted while modulating
at 1kW. Normally satisfactory modulation tracking should be
obtained within two turns of where the control was previously
set. Also note that it is normal for the power output to change on
all power level settings if the Offset control is adjusted.
5.6.2 Analog Input Board A35
The Analog Input board has five adjustments that are normally
preset during factory tests but it is normally advisable to recheck
these settings using the procedures given here. It may be necessary to install the board quickly and therefore return the transmitter to the air without spending time to perform these tests. In
this case the controls could be set to the same resistance values
as the board to be replaced to get the transmitter back on the air
assuming that the controls on the board to be replaced have not
been changed from their correct settings. The controls to be
preset, and the most convenient convenient measurement points
given are as follows:
Note the Dither Frequency adjustment is always factory set and
should not need any further adjustment. If the dither frequency
needs to be changed, connect a frequency counter to TP10 and
adjust R41 for a nominal frequency of 72kHz. This is not a
critical frequency and can vary anywhere from 70kHz to 74kHz.
The remainder of the controls can be set in the following order
5.6.2.1 Maximum Power Adjust A35R27
To set the Maximum Power Adjust, turn on the transmitter to
LOW power with no audio modulation. If the transmitter LOW
power was preset to 1 kW for example, the transmitter should
now be operating at around 1 kW if the Maximum Power control
was preset properly on the new board. If the power is not near 1
kW adjust A35R27 for 1 kW power output. Now depress the
HIGH power button. If the HIGH power was preset for 10 kW,
the transmitter output should now be approximately 10 kW. Now
depress the Power RAISE button until the power output reaches
12 kW or stops raising. If the power output stops raising before
reaching 12 kW, adjust the Maximum Power adjust A35R27 to
12 kW output power. If the power output exceeds 12 kW adjust
R27 down to 10 kW. Hold the raise button again until the power
reaches 12 kW or stops increasing. Set A35R27 so that the
transmitter power will not exceed 12 kW.
5.6.2.2 Modulated B- Adjustments A35R85 (Gain) and
A35R84 (Offset)
The Gain control adjustment A35R85 is normally set maximum
clockwise (max. resistance) and should require no further adjustment. Normally once the Offset control is preset, there is no need
for readjustment, but if it is desired to check the Offset control,
connect a scope from the DC regulator board A30TP7, which is
the modulated B- output. Operate the transmitter at 1 kW and
modulate it with a sine wave at 100% modulation. Set up the
scope to measure an audio wave form DC coupled, 1V per
division. At this point you will see a distorted audio sine wave
of approximately 2Vp-p on a negative DC offset of around
03/16/2009
3VDC. See Figure 5-13. Adjust The Offset control A35R84 such
that the positive peak of this wave form just begins to clip, then
back off the control slightly. Note that the wave form will reach
the clip point as it moves more positive. Also note that this
positive peak of audio actually corresponds to the modulation
envelope negative peak. For more information concerning the
Modulated B- setup, see “Overall Modulated B-Adjustment”.
5.6.2.3 Audio Gain Adjust A35R15
The Audio Gain Adjust is normally factory preset to 100%
modulate the transmitter with an audio input level of +10dBm.
It can however be reset to allow 100% modulation with audio
input levels from -10dBm to +10dBm. To adjust this control
operate the transmitter at the desired output power and slowly
increase the audio output of the audio generator to the desired
output level. If the transmitter reaches 100% modulation before
this point, adjust A35R15 to lower the modulation. Once the
desired generator output level is achieved, adjust A35R15 to
obtain 100% modulation. Note that some change in transmitter
output level may occur when this control is varied so once the
Audio Gain control is set, the transmitter power output may need
to be reset to the desired output using the RAISE and LOWER
buttons.
5.6.2.4 Dither Level Adjust A35R43
Normally if the Dither control is properly preset, there should be
no need for readjustment. If it is desired to check the setting of
the control, then the following procedure is used. Operate the
transmitter at approximately 200W output and modulate it with
a 100Hz tone at 95% modulation. On a scope display one cycle
of the demodulated audio out of the modulation monitor. Expand
the vertical sensitivity of the scope to display only a portion of
the wave form. Adjust the Dither Level control A35R43 to
maximum counterclockwise. At this point it should be possible
to see some of the individual voltage steps that make up the
modulated envelope using the Digital Modulation technique. It
may be possible to see the steps better at a lower modulation
level, but it may also be necessary to sync the scope externally
using the audio generator. Now while observing the individual
steps, adjust the Dither Level Adjust A35R43 clockwise until the
individual steps can no longer be distinguished. This should
occur within two turns of the control R43. Additional turns
clockwise of the control may appear to smooth out the steps
further but at this time additional noise will appear on the wave
form. Again only increase the Dither Level to just smooth out
the small step transitions. Other slightly larger steps or glitches
will be seen at these low power and modulation levels, but the
Dither Level should not be used to smooth out these. Never use
more than 3 turns clockwise of Dither.
5.6.3 Oscillator A17
The oscillator contains jumpers, one four section DIP switch, one
variable inductance, and the frequency trimmer capacitors, all of
which must be properly set up when a new board is installed. To
preset the replacement board before installation, place the following jumpers in the same positions as in the board to be
replaced.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-5
Locate S1, a four section DIP switch, and set each section to the
same setting as the board to be replaced. Locate L4 and using a
non-inductive tuning tool set the slug in the coil for approximately the same amount of penetration into the coil. Lastly, set
the two variable trimmer capacitors (C2 and C4) to about the
same position as on the board to be replaced. Carefully remove
the crystals Y1 and Y2 from their holders by first removing the
heater assemblies from the crystals. An angle bracket that bolts
to the PC board holds the crystal heaters in place. Carefully
remove the crystals and reinstall them on the new board. Place
the crystal heater assemblies over each crystal and replace the
mounting brackets.
NOTE
When replacing the old oscillator board, note in which direction
the plug P3 attaches to J3 on the oscillator board. This connector can be reversed from the wiring diagram to allow proper
phasing of the Oscillator Sync circuit. Possible damage to the RF
Amplifiers could result during a VSWR condition if the plug is
not installed properly.
Two adjustments are now required once the new board has been
installed and made operational.
5.6.3.1 Carrier Frequency Adjust A17C1 and A17C3
Select crystal oscillator Y1 by moving jumpers J1 and J6 to
position 1-2. This also selects crystal heater Y1. Allow the
transmitter to operate with at least the low voltage on for 15 to
20 minutes. Now connect a frequency counter to the BNC
connector J5. Adjust C2 using a non-inductive tool to set the
carrier frequency for the correct indication on the frequency
counter. To set the output frequency of crystal Y2, turn off the
low voltage and now move the jumpers J1 and J6 to positions
1-3. Apply the low voltage and allow 5 to 10 minutes for the
crystal to stabilize in temperature. Now the frequency can be
measured and adjusted using C4.
5.6.3.2 Oscillator Sync Adjustment A17S1 and A17L4
The Oscillator Sync adjustment is critical to the proper operation
of the VSWR circuitry in the transmitter. If this circuit is not set
properly, damage to the RF Amplifiers could result during a
VSWR condition.
Using a dual trace scope connect channel 1 to TP5 on the
oscillator board and channel 2 to TP4 on the oscillator board.
Sync the scope to channel 1. Apply the low voltage and note a
5Vp-p square ware at the RF carrier frequency on scope channel
1. Set the sweep speed on the scope to display one or two cycles
of RF. Operate the transmitter at 10 kW with no modulation. At
this time note that channel 2 will also have a 5Vp-p square wave
displayed. If the positive going edges of the two wave forms are
lined up, no further adjustments are required. If the trace on
channel two is not aligned in phase, (Figure 5-15) adjust L4 to
make them line up as seen in Figure 5-16.
If by adjusting L4 the two wave forms will not line up, then
different combinations of capacitance as selected by S1 can be
switched in to provide various amounts of phase shift. If it
appears that the two signals are 180 degrees apart then the plug
P3 can be reversed at J3. This should not be the case if the board
is simply being replaced assuming the plug position was noted
before removal. Note that when switching in different values of
5-6
capacitance, try to use the least amount of capacitance (S1-1,2
and 3) to achieve phase alignment of the two signals. If too much
capacitance is used there may not be enough signal input to
produce a signal at TP4. Operate the transmitter at 1 kW and note
that the two signals may not be as well aligned as at 10 kW but
make sure there is still a signal at TP4.
5.6.4 Driver Supply Regulator A22
The Driver Supply regulator has two controls and one switch that
should be preset and then checked when replacing this board.
These two controls set the proper drive level to the RF Amplifiers
and should be set properly for the best transmitter operation. Also
if the Driver Supply Regulator is still operational and the drive
level is known to be correct, note down the RF DRIVER SECT
1A and SECT. 1B voltage reading on the multimeter inside the
center compartment. If the Regulator is not operational then note
the Driver Section 1A voltage on the factory test data sheet.
5.6.4.1 Open Loop Adjust A22R2, Closed Loop Adjust
A22R12, Loop Select A22S1
To prevent unnecessary drive overloads, it is recommended that
the two adjustments be preset by measuring the resistance of the
controls on the board to be tested. The controls and the most
convenient measurement locations are as follows.
Set S1 to the OPEN LOOP position and install the replacement
Regulator. On the Controller Board A38 switch the PA TURNOFF switch to the PA-OFF position. Apply the low voltage to
the transmitter and depress the LOW power pushbutton. At this
point high voltage will be on but no power output or PA current
should be noted. On the RF Multimeter on the inside right center
compartment wall note the DRIVER SECT.1A voltage. If the
voltage measured is close to the previously measured voltage or
that which is on the factory test data sheet, then no further
adjustment of the Open Loop control is necessary. If adjustment
is necessary, use an insulated tuning tool to adjust A22R2 to the
voltage noted in the test data. This can be done through the access
holes located just below the oscillator board on the right side
wall. Now using these same access holes, use the tool to switch
S1 to the closed loop position. Adjust A22R12 (Closed Loop
Adjust) so that the DRIVER SECT 1A voltage is the same as
what was set with the Open Loop Adjust A22R2. Return the PA
TURN-OFF switch to the PA-ON position and readjust A22R12
to the correct reading with normal power output from the transmitter if the reading has changed.
It is recommended that the drive level be measured at the RF
Amplifiers to ensure that the Driver section is working properly.
For Drive Level and Phasing measurement procedures see
“MEASURING RF DRIVE LEVEL,” and “MEASURING RF
DRIVE PHASING,” in the Troubleshooting section of the manual.
5.6.5 DC Regulator A30
The DC Regulator has two adjustments which should be preset
before the transmitter high voltage is turned on. To do this simply
measure the resistance of each control on the board to be replaced
assuming these controls have not been tampered with and set the
controls on the new board to these values. The setup procedure
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
on these controls once the new board has been preset and
installed is as follows.
5.6.5.1 Modulated B- Level A30R38, and Clip Adjust
A30R39
Turn on only the low voltage on the transmitter. Connect a scope
to TP7 on the DC Regulator A30. Set the scope to DC coupled,
1V per division, and move the trace so that 0.0V is at the top line
of the scope. Set the timebase to measure audio frequencies.
With just the low voltage on, you should be measuring from -2.0
to -2.3 VDC. If the voltage is not in this range adjust the B- Level
control A30R38 to a nominal -2.1VDC. Now operate the transmitter at 1 kW modulated 100% with a 100Hz sine wave. The
display on the scope will be a distorted sine wave similar to the
one in Figure 5-13. The negative peak of the wave form should
extend down to between -3.0 and-4.5VDC. If it doesn’t, adjust
the Clip Adjust A30R39 to set the negative peak of the wave
form to approximately -4.0VDC. Now operate the transmitter at
10 kW output at 100% modulation at 100Hz. The negative peak
of the wave form should now be between -4.5 and -5.0VDC, with
-4.5VDC being typical. In no case should the negative peak of
this wave form exceed -5.0VDC at 140% positive peak modulation. Voltages greater that -5.0VDC could cause RF Amplifier
failures.
5.6.6 Output Monitor A27
The Output Monitor performs three main functions:
• Forward and reflected power metering
• VSWR overload sensing
• Modulation monitor sample level adjustment
All of these functions must be calibrated for proper transmitter
operation. Set all jumpers and switches to the same position as
on the board to be replaced.
Since all of these circuits require adjustment while the transmitter output network is set to 50 + j0 Ohms, it is preferred that the
transmitter be operated into a 50 Ohm load. This procedure can
be performed into the antenna, but operating the transmitter into
a load will make measurements easier due to the lack of interference, compared to that existing on the antenna system.
5.6.6.1 DETECTOR NULL (Antenna) Adjustment
a. Set the PA TURN-OFF switch S2 on the Controller to the
OFF (up) position.
b. Depress the LOW power button. The PA Supply voltage
should be present but no power should be indicated on the
Forward Power meter.
c. Depress and hold the LOWER button for approximately
30 seconds.
d. Set the PA TURN-OFF switch S2 on the Controller to the
ON (down) position and hold the RAISE button until the
transmitter output power is approximately 500 W.
e. Using a Dual trace scope, connect a 10x probe on channel
1 to TP6 and a 10x probe on channel 2 to TP5. A signal
should be visible at both TP6 and TP5.
03/16/2009
f. While depressing momentary button switch S5, set the
Normal/Calibrate switch S8 to the Calibrate position. Note
that the signal at TP5 has dropped in amplitude.
g. Adjust capacitor C29 for minimum signal at TP5. This
signal will contain mostly harmonics of the carrier frequency. It may be necessary to add additional capacitance
with S9-1 and S9-3 at the low end of the band or additional
inductance with S9-2 and S9-4 at the high end of the band
to achieve a minimum signal.
h. Set the Normal/Calibrate switch S8 to the Normal position
and release momentary pushbutton switch S5. Make sure
that the vertical sensitivity of both channels of the scope
are the same.
i. Connect both scope probes to TP6 to ensure that both
traces are the same amplitude. Return the other probe to
TP5.
j. Set the time base on the scope to display 2 to 3 cycles of
RF.
k. Adjust C15 to make the signal at TP6 the same amplitude
as TP5. Note that the two signals are probably not in phase
with each other. See Figure 5-12.
l. Using a non-inductive tuning tool, adjust L12 to phase
align the two signals. It may be necessary to readjust C15
to make the two signals equal in amplitude. Note that it
may not be possible to get both signals equal in amplitude
using C15 until some adjustment of L12 is made.
m. If, by adjusting L12, it is not possible to align the two
signals in phase, select a different value of capacitance
across L12 by switching in one or more sections of S6 then
readjusting L12 for an in phase signal.
n. Note that as the amplitude and phase of the two signals
are matched, the meter reading in the DETECTOR NULL
(Antenna) position will null. Fine adjustments of these
controls will be made at full power once the Bandpass
Filter controls are set.
5.6.6.2 DETECTOR NULL (Bandpass Filter) Adjustment
a. Using a Dual trace scope connect a 10x probe from channel 1 to TP10 on the Output Monitor. Connect a 10x probe
from channel 2 to TP1. A signal should be visible at both
TP1 and TP10.
b. While depressing the momentary pushbutton switch S5,
set the Normal/Calibrate switch S8 to the Calibrate position. Note that the signal at TP10 has dropped in amplitude.
c. Adjust capacitor C21 for minimum signal at TP10. Also
note that the minimum residual signal will contain mostly
harmonics of the carrier frequency.
d. If a minimum cannot be achieved due to the capacitor C21
running out of range, use S1 to select a different value of
capacitance (C3 or C5), or a different value of inductance
(L2 or L3) to null out the signal at TP1. Note that some
frequencies may not require any added reactance. Normally capacitance is added at the low end of the frequency
band and inductance is added at the high end of the band.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-7
e. Set the Normal/Calibrate switch S8 to the Normal position,
and release momentary pushbutton switch S5. Make sure
that the vertical sensitivity of both channels of the scope
is the same.
f. Set the time base on the scope to display 2 to 3 cycles of
RF.
g. Adjust C16 to make the signal at TP1 the same amplitude
as TP10, and also note that it may not be possible to get
both signals equal in amplitude using C16 until some
adjustment of L5 through L8 (selected by S7) is made.
Capacitance can be added with S2 if the signal cannot by
nulled with C16.
h. Note that the two signals are probably not in phase with
each other. See Figure 5-12.
i. Using a non-inductive tuning tool, adjust L5 through L8,
depending on which one is selected by the DIP switch S7,
to phase align the two signals. It may be necessary to
readjust C16 to make the two signals equal in amplitude.
j. If, by adjusting the selected variable inductor L5-L8, is not
possible to align the two signals in phase, select another
value of variable inductance with S7. Note that as the
amplitude and phase of the two signals are matched the
DETECTOR NULL (Filter) position on the Multimeter
will also null.
5.6.6.3 Fine Tuning
a. With the transmitter operating at 500 W, both the DETECTOR NULL (Antenna) and the DETECTOR NULL (Filter) positions on the front panel multimeter should indicate
near zero.
b. To prevent possible modulation monitor damage, turn
both the MEDIUM and HIGH power modulation monitor
adjustment controls R7 and R8 full CCW.
c. Bring the transmitter to 10 kW (15 kW on the DX15) and
note the DETECTOR NULL (Antenna) position on the
multimeter. If the reading is now above zero, null this
reading using both C15 and L12.
d. Note the DETECTOR NULL (Filter) indication on the
multimeter. If it is above zero, null it using C16 and L5
through L8, depending on what was selected by S7. The
final adjustments will be made into the antenna at full
operating power.
e. Modulate the transmitter with a 10 kHz tone, or one which
causes the greatest upward deflection on the DETECTOR
NULL (Antenna) meter reading, and recheck nulls.
f. Use a digital voltmeter or a dc coupled oscilloscope and
adjust for minimum voltage at TP8 and TP9 with reference
to ground.
5.6.6.4 Trip Threshold Adjustment
The overload settings for the Antenna and Bandpass circuit are
listed in the Factory Test Data sheet. After the replacement board
has been installed, set the overload settings as follows;
5.6.6.4.1
c. Adjust R24 until the voltage matches the Factory Test Data
sheet.
If the Factory Test Data sheet is unavailable or if it is necessary
to verify the original overload setting, use the following procedure:
a. Verify that the DETECTOR NULL (Antenna) reading on
the front panel multimeter is nulled (zero) at full power.
b. Press LOW power, and adjust the RF output for 600 W on
the DX10 or 900 W on the DX15.
c. Depress the OFF button.
WARNING
ENSURE ALL PRIMARY AC VOLTAGE HAS BEEN REMOVED
FROM TRANSMITTER AND A GROUNDING STICK IS USED TO
GROUND ALL POINTS WHERE AC OR RF POWER HAS BEEN
APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
d. Remove the rear panels from the Output Network Compartment.
e. Reverse the Antenna VSWR current sample by placing P1
from 1-2 and P2 from 2-3 on the Output Sample Board.
f. Replace the rear panels on the Output Network Compartment.
g. Restore primary ac voltage at the main breaker.
h. Depress the LOW power button.
i. Switch the front panel multimeter to the DETECTOR
NULL (Antenna) position. Note that the meter reads upscale.
j. Adjust R24 until the transmitter indicates an ANTENNA
VSWR fault condition on the ColorStatÔ panel.
k. Turn the transmitter OFF.
WARNING
ENSURE ALL PRIMARY AC VOLTAGE HAS BEEN REMOVED
FROM TRANSMITTER AND A GROUNDING STICK IS USED TO
GROUND ALL POINTS WHERE AC OR RF POWER HAS BEEN
APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
l. Remove the rear panels from the Output Network Compartment.
m. Place P1 and P2 on the Output Sample Board in the Normal
position.
n. Replace the rear panels on the Output Network Compartment.
5.6.6.4.2
Bandpass VSWR Overload
a. Turn on the Low Voltage at CB1 and CB2.
b. Connect a voltmeter to TP3.
c. Adjust R23 until the voltage matches the factory test data
sheet.
Antenna VSWR overload
a. Turn on the Low Voltage at CB1 and CB2.
b. Connect a voltmeter to TP4.
5-8
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
5.6.6.5 Forward/Reflected Power Adjustments C6 and C40
a. With the transmitter operating at 10 kW (15 kW on the
DX15) and no modulation, read the Reflected power indication on the front panel meter.
b. Adjust C40, Reflected Balance control, to null the meter
indication. Note that C30 is added by P2 at the low end of
the band to allow the meter indication to null.
c. Depress the OFF button.
d. Locate P1 and P3 on the Output Monitor. Move both
jumper plugs from position 1-2 to position 1-3.
e. Turn the transmitter back on at full power. Note that the
Reflected meter position now indicates forward power and
the Forward meter position now indicates reflected power.
f. Operate the Forward/Reflected meter switch to the Forward power position. Adjust C6 to null this indication.
g. Depress the Off button and move jumpers P1 and P2 to
position 1-2.
5.6.6.6 Modulation Monitor Sample Adjustments
Refer to the Initial Turn-On procedure in SECTION II, Installation/Initial Turn-On, for the procedure to set the Modulation
monitor sample adjustments.
5.6.7 LED Board Replacements A32
The LED board contains 7 controls which can be preset to the
same resistance value or reference voltage as on the board to be
replaced assuming that these controls have not been tampered
with. Therefore it is possible to preset the board before high
voltage is applied and be assured the overloads are set at their
previous operational setting. The procedures for setting each of
these overloads will be given here in case the original settings of
the overload controls are not known to be correct.
Presetting the LED Board Controls. With low voltage still applied to the board to be replaced measure the voltages at the
following test points and record them below. These are the
reference voltages for some of the overloads and will be used to
preset the replacement board.
Disconnect power from the transmitter and remove the LED
board. Now measure the resistance of the following points on the
just removed LED board to allow presetting of the replacement
board.
Note that on U25, when looking from the top, Pin 1 is the first
pin counter-clockwise from the TAB (pin 10). Count the pins
counter-clockwise from pin 1.
Now preset the replacement board controls to the same resistances as noted earlier. Install the replacement board into the
transmitter making sure all connectors are attached to the correct
jacks on the LED board. Apply the main power to the transmitter
and verify that only the low voltage is on. At this time all the
fault indicators on the LED board should indicate green. If any
indicator is red, depress the reset button on the front panel to
clear the fault. If any fault remains red then refer to the troubleshooting section to isolate the problem. Measure the voltages
at the test points listed earlier and adjust the appropriate control
03/16/2009
to measure the same voltage. The transmitter is now ready for
application of high voltage.
5.6.8 Overload Adjustment Procedures
The following are the procedures used to set the individual
overloads on the LED board. These overloads should be checked
when a board is replaced, or when a part failure occurs in the
transmitter especially in the PA or power supply sections.
5.6.8.1 Under drive Overload A32R92 and Overdrive Overload A32R88.
The drive overloads function to protect the RF Amplifiers from
drive levels which could cause damage to the RF Amps. Typically the RF Amplifiers should not be operated at drive levels
below 20Vp-p or above 27Vp-p. The nominal drive level is 23
to 24Vp-p. These levels are measured at the gate of the MOSFET’s on the RF Amps. The first step in setting the drive
overloads is to remove the supply voltage from all the RF Amps
so that no Damage will occur while the drive level is varied. Next
the drive level will be varied to the overload limits and the
overloads will be set.
WARNING
ENSURE ALL POWER IS REMOVED FROM THE TRANSMITTER
AND THAT GROUNDING STICK HAS BEEN USED TO DISCHARGE ANY RESIDUAL POTENTIAL WHERE POWER HAS
BEEN APPLIED BEFORE PERFORMING THE FOLLOWING
STEPS.
To remove the Supply voltage from the RF Amps first remove
all primary power from the transmitter. Open the front door to
the Power Supply cabinet and locate the Fuse Board A24 on the
left hand wall of the Power Supply compartment. Now remove
fuses F2 through F7. Note that F3 is not the same value as the
others. Close the Power Supply cabinet and now open the inner
front door exposing the RF Amplifiers. Locate RF Amplifier
Step 1 (bottom left RF Amp). Connect a X10 scope probe to the
left hand side of CR3 which is located in front of the heat sink.
Connect the probe such that the lead can be safely routed out the
interlocked door once it is shut, and the probe will not interfere
with the closing of the inner door. Connect the ground clip of the
probe to the edge of the front of the RF amp card on either side
of the round hole in the front middle of the card. Note that this
is the ground plane for the RF Amplifier. Connect the probe to
the scope set up to measure an RF wave form at approximately
24Vp-p. Close the inner front door of the RF compartment and
apply primary power. NOTE: A X10 SCOPE PROBE MUST
BE USED. ALSO ENSURE THAT THE SCOPE CASE IS
PROPERLY GROUNDED.
Depress the LOW power on button and note that the high voltage
comes up as indicated on the front panel multimeter but no RF
power or PA current is indicated. With the scope DC coupled
note that an RF sine wave is now displayed on the scope. The
wave form should measure from 22 to 25Vp-p and it should be
centered on the 0.0VDC line of the scope. If the wave form falls
totally below the 0.0VDC line of the scope, the Step 1 amplifier
is turned off. See Figures 5-10 and 5-11 for drive wave forms.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-9
NOTE
When measuring RF Amplifier drive amplitudes or phasing, the
amplifier to be measured must be turned on to give a correct
drive measurement. The drive wave form of an “OFF” amplifier
will be below 0.0VDC and the peaks will probably be clipped.
To turn on an amplifier first make sure that the PA TURN-OFF
switch on the Controller board is set to the PA-ON position. Next
depress the RAISE button until the desired amplifier turns on as
indicated by the correct drive wave form. Note that at 0 kW
output no big step amps are on. As the power is raised the big
steps will successively turn on to increase the power output.
There are 42 Big Step Amplifiers, but even at 11 kW of carrier
power only Big Step Amplifiers 1 through 19 will be turned on.
Therefore holding the raise button will only turn on up to Step
18. To turn on any higher steps these must be manually turned
on using the FlexPatch™ feature on the Modulation Encoder
board A36. For information on performing this procedure see
“MEASURING STEPS 18-42,” in the Troubleshooting section
of the manual.
Measure the peak to peak drive level on the scope monitoring
the drive at Step 1. Also record the reading on the RF Multimeter
position for DRIVER SECT.1A. The drive will be set back to
this voltage once the overloads are set. Now locate the access
holes for the Drive Supply regulator A22 Closed Loop adjustment control A22R12. These are located just above the oscillator
board. Using a non-metallic tool, adjust R12 CCW noting that
the p-p drive level is decreasing along with the voltage on the
RF Multimeter for DRIVER SECT.1A. Turn this control until
the drive level on the scope reaches 20Vp-p. Now adjust A32R92
on the LED board until the transmitter turns off. It will try to
restart, but will again turn off and display a red LED on the
Mimic panel Under drive fault. Turn the closed loop adjustment
back a few turns CW to allow the transmitter to restart. If by
turning the Closed Loop control, the drive level does not drop to
20Vp-p, note the voltage on DRIVER SECT. 1A. If it is now 0V
then the drive cannot be reduced any further. If the drive level is
between 20 and 22Vp-p the Under drive overload can be set at
this level and should not cause nuisance under drive overloads.
Now adjust the Closed Loop control R12 CW until the drive level
reaches 26Vp-p. Adjust the Overdrive overload A32R88 until
the transmitter overloads and recycles. Note that a Overdrive
overload is indicated on the front Mimic panel. Turn the Closed
Loop adjustment R12 few turns CCW to restart the transmitter.
Now readjust R12 to the same voltage as earlier recorded on the
multimeter DRIVER SECT 1A. This should also correspond to
the same RF drive level first noted.
WARNING
ENSURE ALL POWER IS REMOVED FROM TRANSMITTER AND
THAT GROUNDING STICK HAS BEEN USED TO DISCHARGE
ANY RESIDUAL POTENTIAL WHERE POWER HAS BEEN APPLIED BEFORE PERFORMING THE FOLLOWING STEPS.
Depress the OFF button and remove primary AC power. Open
the front door to the Power Supply compartment and replace
fuses F2 through F7 on the Fuse Board A24. Again F3 is a
different value fuse.
5-10
5.6.8.2 Average PA Current Overload Set A32R102
Operate the transmitter at 10 kW output power. Modulate it with
a 20Hz square wave to 100% modulation. Increase the audio
modulation until the PA current on the meter indicates 97A
+/-1A. Adjust R102 CW until the transmitter turns off. It will
attempt to start again but will overload and remain off. Note that
the Supply Current overload LED will be illuminated red. Remove the audio modulation and depress the Reset button on the
Mimic panel. The Fault indicator should turn green and the
transmitter should be able to be turned on again.
5.6.8.3 Peak PA Current Overload Set A32R98
Operate the transmitter at 10 kW output power. Apply a 20Hz
triangle or asymmetrical sine wave modulation to allow the
transmitter to modulate to the positive peak clip level as seen on
the RF envelope displayed on a scope. Now while the transmitter
is modulating adjust A32R98 clockwise until the transmitter
begins to trip off on a Supply current overload. Adjust the control
counterclockwise 1 turn from the trip point. Now apply a relatively dense program material. Set up the audio processor such
that the modulation level and density would be the slightly above
the highest expected during normal programming. Ensure that
this type of programming does not cause Supply current overloads on modulation positive peaks. Turn A32R98 counterclockwise if required to prevent false trips due to modulation. Return
the transmitter to normal power output and modulation levels.
5.6.8.4 Power Supply Protection Overload A32R23
Operate the transmitter at 11 kW output power. Modulate the
transmitter with 120Hz at 100% modulation. Increase the audio
modulation 0.5dB (6%). Note: Use 100Hz modulation if operating at 50Hz AC line frequency. Adjust A32R23 clockwise until
the transmitter turns off. Adjust the control 1/4 turn counterclockwise. Note that the transmitter will not recycle for this fault.
Note that the Supply Fault LED in the Mimic panel is illuminated
RED. Depress the reset button to reset the fault indicator to
green.
NOTE
It is not required that the Reset button on the Mimic panel be
reset to restart the transmitter.
5.6.8.5 Envelope Error Fault Indicator A32R65 (Level) and
A32R68 (Offset)
Set the LOW, MEDIUM, and HIGH power levels to 1 kW, 5 kW
and 10 kW respectively. Using a meter capable of measuring
100mV full scale, connect the + lead of the meter to TP14 on the
LED board A32. Connect the - lead to TP13 on A32. Depress
the LOW power button with no modulation. Adjust the Offset
control A32R68 for and indication of 130mV on the meter.
A32R65 can also be adjusted if the offset adjustment alone will
not achieve this voltage. Now depress the HIGH power button
and adjust the Level control A32R65 until the voltage indicates
130mV. Repeat these steps until both high and LOW power
indicate 130mV on the meter. Also measure the voltage when
operating at 5 kW output to ensure that it is also 130mV +-5mV.
Both controls interact but typically the level control R65 affects
the HIGH power and the Offset control affects the LOW power.
To verify operation of this circuit, locate the gold jumper plugs
on the Modulation Encoder board for Big Steps 4 and 5. Remove
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
these two jumpers. At all operating powers note that the power
output is now 10 to 20% lower than normal and that the Envelope
Error LED is now illuminated RED. This should occur at all
power levels.
NOTE
The operation the the Envelope Error detection circuitry is load
dependent. Therefore these adjustments should be performed
while the transmitter is operating into the normal load (antenna),
and the Loading and Tuning controls have been set for a minimum indication on the Antenna Null position of the multimeter.
Once the adjustments are made, if the transmitter is operated into
a different load without retuning it is possible for the envelope
error LED to illuminate RED when no fault exists in the transmitter.
5.7 Board Replacement Instructions
The following will give specific instructions designed to assist
in the removal and replacement of a few of the boards that require
more than just the removal of a few screws. Instructions on
replacing the blower motor are also given.
5.7.1 Main Combiner/Motherboard Replacement
A19 and A20
The Main Combiner/Motherboards will most likely not require
any service through the life of the transmitter, but if service or
replacement is required the following procedure can be used.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
The two Main Combiner/Motherboards are the center and bottom boards in the RF compartment. If only removal of the center
board is required, only that board needs to be removed. If the
bottom Main Combiner/Motherboard needs to be removed, then
both the middle and the bottom board must be removed. Remove
the middle Main Combiner/Motherboard as follows.
Open the front middle door and the front inner door exposing the
RF Amplifier modules. Remove RF Amplifiers Step 5 through
Step 12 and Step 29 through Step 36. Even though it is not
necessary, it is recommended that the modules be labeled or kept
in an order such that they can be replaced in their original slots.
From where the modules were removed, locate and disconnect
J21 through J26. Also in the front remove the #4 screw that is
located in the center partition, at the center of the motherboard.
Look for the long aluminum standoff coming from the center of
the PC board. From the rear of the transmitter remove the four
drive cable assemblies that attach to the sides of the motherboard
at J17 through J20.
At this time remove the Combiner cover by removing the #4
screws that attach the cover to all three motherboards, the four
#6 screws that attach the brackets to the top of the cover, the four
#6 screws that attach to the lower Combiner cover, and the four
03/16/2009
#6 and one #8 screws that are located on the Combiner cover at
the Driver Combiner/Motherboard. Lastly remove wire #151
that connects R38 to the Binary Combiner/Motherboard at J29.
The Combiner cover should now be able to be removed. It may
be necessary to move some of the drive cable assemblies to the
side at the drive splitter to get the cover out.
At this time the Combiner toroids will be visible with the single
turn secondary copper rod running through the middle of the
toroids. Locate the point where the copper rod connects to the
upper and lower Combiner/Motherboards. Use a 3/16" allen
wrench to remove the screws that bolt the rods together. Lastly,
remove the six #6 screws that mount the Motherboard to the side
rails. The whole assembly can now be removed from the transmitter.
CAUTION
CARE SHOULD BE TAKEN WHEN INSTALLING, REMOVING AND
SERVICING THE COMBINER/MOTHERBOARDS. THE LARGE AIR
CORE COILS CAN BE DAMAGED DURING HANDLING. ALWAYS
CHECK TO MAKE SURE THAT NO TURNS OF THE COILS HAVE
BEEN INADVERTENTLY SHORTED OR THE TAPS ON THE COILS
ARE MOVED SUCH AS TO SHORT TURNS.
5.7.2 Replacement of the Main Combiner/Mother-
boards
Replacement of the Main Combiner/Motherboards is essentially
the reverse of the removal procedure. During installation of the
motherboard, it may not appear it fit in as easily as it came out.
This is due to the blue card guides not fitting back in their slots
at the same time. It is recommended that the board be installed
and just a few of the screws be installed that mount the board to
the supports. Then from the front of the center compartment,
place the card guides into their respective slots. Once the motherboard has been fully mounted insert the allen screws that bolt
the Combiner rods together in place but do not fully tighten.
Loosen the two set screws that are on the fiberglass supports on
the motherboard that hold the rod in place. Now tighten the Allen
screws on the copper rod to 85 inch/lbs. Retighten the set screws
on the motherboard. Replace the Combiner cover, RF Amplifier
modules, and the interconnection plugs.
5.7.3 Lower Main Combiner/Motherboard Replace-
ment
As noted earlier the middle Combiner/Motherboard must be
removed first using the preceding procedure. This same procedure can be used to assist in removal of the bottom board with
the addition of the removal of RF Amplifiers Big Steps 13
through 28, and a small cover on the top of the bottom Combiner
cover. This will assist in removal and replacement of the two
allen screws that bolt the bottom of the copper rod. The bottom
Combiner/Motherboard must then slide upward into the area
where the middle Combiner/Motherboard was before being able
to pull it straight out.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-11
5.7.4 Binary Combiner/Motherboard Removal and
Replacement A18
The Binary Combiner/Motherboard is replaced in the same
manner as the Main Combiner/Motherboards. The only differences being that the RF Amplifiers to be removed are Big Steps
1 through 8 and Steps 41 and 42. Also Binary amps B-7 through
B-12 need to be removed. Two additional plugs P27(Modulation
Encoder cable) and P28 (Step 41 and 42 B+) also need to be
disconnected before the motherboard can be removed.
5.7.5 Driver Combiner/Motherboard A14 Removal
and Replacement
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Open the front middle door and the front inner door exposing the
RF Amplifier modules. Remove the RF Driver modules A41A43, the Predriver module A10, and the Buffer Amplifier A16.
Even though it is not necessary, it is recommended that the
modules be labeled or kept in an order such that they can be
replaced in their original slots. From where the modules were
removed, locate and disconnect J1-J5 and J11-J12. Some of these
connectors may be more accessible from the rear. Also in the
front remove the #4 screw that is located in the center partition,
at the center of the motherboard. Look for the long aluminum
standoff coming from the center of the PC board.
At this time remove the Combiner cover by removing the #4
screws that attach the cover to all three motherboards and the
Driver Combiner Motherboards, the four #6 screws that attach
the brackets to the top of the cover, the four #6 screws that attach
to the lower Combiner cover, and the four #6 and one #8 screws
that are located on the Combiner cover at the Driver Combiner/Motherboard. Lastly remove wire #151 that connects R38
to the Binary Combiner/Motherboard. The Combiner cover
should now be able to be removed. It may be necessary to move
some of the drive cable assemblies to the side at the drive splitter
to get the cover out.
Now the Combiner toroids will be visible with the single turn
secondary copper rod running through the middle of the toroids.
Locate the point where the copper rod connects to the Binary
Combiner/Motherboard. Use a 3/16" allen wrench to remove the
screw that bolts the rods together. From the top of the transmitter,
locate the access plate that is in the center of the top of the
transmitter. Remove this cover to expose the Predriver and
Driver tuning coils. Between these coils there will be an access
hole to allow a 9/16" socket wrench to remove the bolt that
connects the top of the Driver Combiner output rod to the RF
Drive Splitter. It will also be necessary to loosen the set screw
that secures the rod to the copper plate in the middle of the
Combiner board. The screws attaching this plate to the motherboard may also have to be removed to allow the Driver Combiner/Motherboard to be removed. Lastly, remove the six #6
5-12
screws that mount the Motherboard to the side rails. The whole
assembly can now be removed from the transmitter.
5.7.6 Replacement of the Driver Combiner/Mother-
board
Replacement of the Driver Combiner/Motherboard is essentially
the reverse of the removal procedure. During installation of the
motherboard, it may not appear it fit in as easily as it came out.
This is due to the blue card guides not fitting back in their slots
at the same time. It is recommended that the board be installed
and just a few of the screws be installed that mount the board to
the supports. Then from the front of the center compartment,
place the card guides into their respective slots. Once the motherboard has been fully mounted insert the allen screw that bolts
the Combiner rods together in place but do not fully tighten.
Loosen the set screw on the copper plate that mounts on the
motherboard. Now replace the bolt that attaches the top of the
Combiner pipe to the Drive Splitter board but do not tighten.
Now tighten the Allen screws on the copper rod to 85 inch/lbs.
Retighten the bolt on the Drive Splitter and the set screw in the
copper plate on the motherboard. Replace the Combiner cover,
Amplifier modules, and the interconnection plugs.
5.7.7 RF Driver Splitter A15, Removal and Replace-
ment
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Open the front middle door and the front inner door exposing the
RF Amplifier modules. Remove the RF Driver modules A41A43, the Predriver module A10, and the Buffer Amplifier A16.
Even though it is not necessary, it is recommended that the
modules be labeled or kept in an order such that they can be
replaced in their original slots.
At this time remove the Combiner cover by removing the #4
screws that attach the cover to all three motherboards and the
Driver Combiner Motherboards, the four #6 screws that attach
the brackets to the top of the cover, the four #6 screws that attach
to the lower Combiner cover, and the four #6 and one #8 screws
that are located on the Combiner cover at the Driver Combiner/Motherboard. The Combiner cover should now be able to
be removed. It may be necessary to move some of the drive cable
assemblies to the side at the drive splitter to get the cover out.
Remove the two brackets that attached to the Combiner cover
and are underneath the Splitter board.
Now the Combiner toroids will be visible with the single turn
secondary copper rod running through the middle of the toroids.
Locate the point where the copper rod connects to the Binary
Combiner/Motherboard. Use a 3/16" allen wrench to remove the
screw that bolts the rods together. From to top of the transmitter,
locate the access plate that is in the center of the top of the
transmitter. Remove this cover to expose the Predriver and
Driver tuning coils. Between these coils there will be an access
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
hole to allow a 9/16" socket wrench to remove the bolt that
connects the top of the Driver Combiner output rod to the RF
Drive Splitter. It will also be necessary to loosen the set screw
that secures the rod to the copper plate in the middle of the
Combiner board. The screws attaching this plate to the motherboard may also have to be removed from the front side to allow
the Combiner rod to slide downward far enough to allow the
splitter board to be removed.
Remove all 12 RF drive cable assemblies from the splitter board.
It is not necessary that the cables be replaced in the same location
as they were removed but it is recommended. Remove the four
screws that mount the Drive Splitter to the top of the RF compartment. At this time the Splitter should be able to be removed.
Replacement of the Drive Splitter is the reverse of the removal
process.
5.7.8 Blower Motor B1 Replacement
WARNING
ALL VOLTAGE HAS BEEN REMOVED FORM TRANSMITTER
AND GROUNDING STICK IS USED TO GROUND ALL POINTS
WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Remove both the rear panels on the RF Compartment (center),
and the Output Network compartment (left). From the RF compartment locate the blower motor in the lower right side of the
compartment. Remove the access cover on the motor and remove
the three wires #46,47 and 48, noting to which set of wires each
on was connected to by wire nuts. From the Output Network
compartment locate and remove the 6 bolts that mount the
blower assembly to the side wall. Remove the 2 screws that bolt
the assembly to the floor of the compartment. Remove the 4 bolts
that mount the combiner pipe insulating plate to the side wall.
Move this plate along the combiner pipe towards L101 far
enough to allow the blower assembly to be removed for servicing.
5.8 Other Transmitter Circuit Checks
5.8.1 Airflow Switch S7 Adjustment
Air switch testing procedure:
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FORM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
a. With the transmitter off, and with all power disconnected,
remove the panel from the power supply section. This is
the far left panel as you are facing the rear of the transmitter.
b. Use the shorting stick to discharge any residual voltages.
03/16/2009
c. Remove fuses F1-F7 from Fuse board, A24. Note the
various amperage fuses as they are removed.
d. Put the rear panel back in place.
e. Remove the center panel. Rotate the air switch adjusting
screw fully counterclockwise.
f. Apply power to the transmitter and depress LOW, MED,
or HIGH. The blower should start running, and there
should be no AIR interlock condition.
g. Rotate the air switch adjusting screw clockwise just far
enough to cause an AIR interlock condition.
h. Put the rear center panel back on the transmitter. The AIR
interlock LED should go out.
i. Open the center door on the front of the transmitter. An
AIR interlock should not occur. If it does, the air switch
adjusting screw will need to be turned counterclockwise
until this condition can be met.
j. Remove AC power, and access the A24 fuse board. Re-install the F1-F7 fuses in their correct order.
5.9 Tuning/Frequency Change Procedure
The following is a step by step procedure on changing the
frequency of the DX-10 Transmitter. If a complete frequency
change is desired this procedure can be followed in order. If a
specific tuning procedure is only desired (ex. RF Driver tuning)
then only that section needs to be looked at. In some cases time
is a consideration in changing frequency of the transmitter. To
allow a faster frequency change, procedures which are performed to achieve optimum transmitter performance, yet are not
critical to the transmitters reliable operation are covered after the
section on “BASIC FREQUENCY CHANGE.”
5.9.1 Test Equipment Required for Frequency
Change
The following is a list of the test equipment required to perform
a frequency change on the DX-10 transmitter. A frequency
change should not be attempted unless the proper equipment is
used.
1.
2.
3.
4.
Audio Generator and Distortion Analyzer
Oscilloscope
Frequency Counter
Modulation Monitor (with a very low residual distortion)
5. Digital Multimeter (preferred)
6. ** Spectrum Analyzer
7. ** Tracking Generator
8. ** Vector Impedance meter
9. Frequency programmable RF Generator (must operate
up to 3 times carrier frequency)
10.Impedance bridge
11.RF Load, 40 kW dissipation
12.Function Generator (optional)
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-13
NOTE: Items 6,7, and 8 are the preferred equipment for setting
up the output network. Items 9 and 10 are substitute equipment.
Procedures for using both are given.
5.9.2 Installation of Frequency Determined Compo-
3f trap
nents
Using the frequency determined components chart in Section 9,
install all the proper parts listed for the new desired frequency.
There are numerous jumpers that are changed but the only
PARTS that need to change or be checked for proper value are
the following:
Note that the Frequency Determining chart for the output network components also lists the mounting hardware required for
each combination of capacitors. When installing these components make sure all connections are tight and use special care
when handling vacuum capacitors.
5.9.3 Setting of Frequency Determined Jumpers and
Switches
Many of the frequency determined components on the DX-10
are permanently installed and are simply changed by moving the
desired jumper, coil tap or switch position. The Frequency
Tuning chart lists all jumpers, taps, and switches that need to be
set per frequency. Some of these settings are considered presets
and may need to change during a specific procedure. A list of
the boards with frequency determined jumpers, taps, preset
adjustments, and switches are as follows.
Probing the third
Harmonic trap
Impedance meter probe
Figure 5-1
Third Harmonic Filter set up.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FORM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
C103 tap
3f trap
5.9.4 DX10/15 Output Network Tuning
1. Dummy load
Connect a suitable 50 ohm non-reactive dummy load to the
output terminal of the transmitter. This can be a small resister,
such as a 1/2 watt to a 2 watt type. Do not use a wire wound
resistor, even if it “non-inductive” and do not use long leads.
2. Third Harmonic Trap Adjustment
Disconnect L105 from L103 and L104. Adjust the tap on L105
for minimum impedance at the third harmonic of the carrier
frequency. This is a very sharp adjustment, so small adjustments
make a considerable difference. Reconnect L105. See figure
5-1.
Probing the 50 ohm point (input
to the TEE network).
3. Tee Network Adjustment
Disconnect the strap from the sand-off below the Output Sample
Board. Connect the impedance meter probe tip to the tubing, and
the probe case to the bracket below the Output Sample toroid.
Adjust the Tuning and Loading controls for 50 ohms, 0 degrees.
Leave the strap disconnected from the standoff below the Output
Sample board for the next step. See figure 5-2.
4. Tank Circuit Resonance
5-14
Figure 5-2
Tee Network set up.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Disconnect L101 from C101. Connect the impedance meter
probe to C103. Use the L102 tap that connects to C103 for this
adjustment. Adjust it to bring the impedance near resonance.
This will be at least 1000 ohms. It is desirable to have the
impedance at a phase angle of about -50 degrees. Experience has
shown that when the back boor is installed, the L102/C103
combination will then be at resonance. This also is a fairly sharp
adjustment. See figure 5-3.
Probing the Tank Circuit
resonance and the Z @ C103
5. Setting the Z @ C103
Reconnect the strap to the standoff below the Output Sample
board. Use the L102 tap that connects to this standoff for this
adjsutment. Connect the impedance meter probe to C103, and
adjust the L102 tap to acheive the figure specified for “Z @
C103.” The phase angle should be close to zero degrees.
Adjust here.
Measure here.
3f trap
6. C101/C102 Adjustment
With L101 Still disconnected from C101, connect the impedance
mater probe across C101. The probe case should be held against
the C101 strap, and the probe tip should be touching the upper
body of C101. Adjust C101. Adjust C101 to achieve the specific
value for Xc101/102. Since you are measuring a pure capacitance, the phase angle should be -90 degrees. See figure 5-4.
7. Setting the Z IN, the PA Combinet Load Impedance
Reconnect L101 to C101. Disconnect the strap from the combiner tubing, and connect the impedance meter to the strap. Hold
Figure 5-3
Tank Circuit set up.
Probing C102/C103
Figure 5-5
Z In measuring point.
3f trap
Adjust for the specified Z In
Figure 5-4
Probing C102
03/16/2009
the case of the impedance meter probe against the shelf. Do not
use clip leads becasue they will alter the impedance measurement. Adjust the C101 tap on L102 and the L101 tap to obtain
the specified impedance designated as “Z In.” This can be a little
tricky because both adjustments will affect both readings on a
vector impedance meter.
8. Restore All Connections
Reconnect the strap to the combiner tubing.
9. Check Voltage Clearances
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-15
C101 adjustment, however be sure to return C101 to it’s earlier
setting. If you find that the network was not already tuned to the
peak, then a small adjustment of L101 should be made. This will
maintain the desired bandpass characteristics and at the same
time present the PA modules with the desired tuning. Based on
experience with this procedure, the final adjustment should not
involve more than an inch of movement on the coil.
Make sure there is
clearance here.
Figure 5-6
Tubing clearance gap.
5.9.5 RF Circuits Checkout
Before the main power is restored to the transmitter, make sure
all FD components have been properly installed. All FD jumpers,
coil taps, and switches have been properly set. Check all connections in the output network for proper tightness, and that all
panels that have been removed have been installed. Remove the
Buffer Amplifier board at this time, and turn the Predriver Level
control R1 (located above the inner front door) maximum counterclockwise.
5.9.5.1 Oscillator A17
Connect a frequency counter to A17J5 (frequency monitor sample). Apply main power to the transmitter and turn on the low
voltage. Allow the transmitter to warm up for approximately 10
minutes, then adjust the trimmer A17C1 for the exact carrier
frequency. If a second crystal is installed in Y2 then set the
jumpers P1 and P6 to positions 1-3. After a short warm-up, adjust
A17C3 to the carrier frequency.
NOTE
Set the frequency close at this point and recheck it later after at
least a 30 minute on time. This must be repeated for both crystals.
5.9.5.2 Buffer A16
Shape this strap away from C101 and C102.
Figure 5-7
Strap clearance.
The top end of C101/102 is be far the highest voltage in the
transmitter. It is very important to check to make sure the
connections around C101 maintain safe distances. This includes
the L101 tubing, which passes by the lower part of C101 on it’s
way to the top. There should be a 1.2" space between the L101
tubing and the nearest surface at the bottom end of C101. If any
reshaping is necessary, avoid putting any physical stress on C101
while doing so. Also check that the L102 strap that runs from the
lower connection plate for C101/102 is shaped away from the
upper part of the capacitors. See figures 5-6 and 5-7.
10.Install the back panel.
11.Final Adjustments.
Be sure that a load with a suitable power rating is connected to
the transmitter output terminal. Gradually increase the power
output of the transmitter from zero. The power output should
already be at or near it’s peak. This can be checked by using the
5-16
Turn off the low voltage to the transmitter by switching S11 off.
Locate the Predriver behind the inner front door, and attach the
scope to the left hand side of CR3. Reapply the low voltage by
turning S11 on. Verify that the drive level to the Predriver is
between 10Vp-p and 20Vp-p. If no signal exists check the right
hand side of CR4. Since only half of the Predriver is used at one
time only the selected half of the Predriver will have drive
applied. The Predriver selection is set by the position of S1 on
the Driver Combiner Motherboard A14. Also note that the drive
wave form to the Predriver will have ringing on it and not be a
clean sine wave. See Figure 5-8.
5.9.5.3 Predriver Adjustment A10
Turn off the low voltage by switching off S11, and open the inner
front door exposing the RF modules. Locate the Driver modules
A41-A43 (Section 1-3). Connect a scope to the left hand side of
CR3 on Driver section 1 (top module). Now turn on the low
voltage using S11. The drive voltage that should be at this point
should normally be between 15Vp-p and 25Vp-p, but it may be
lower at this time. On the RF Multimeter monitor the Predriver
Current. Adjust the Predriver tune control L1 to peak the RF
drive indication as seen on the Gate of the Driver module. The
Predriver current indication on the multimeter should also peak
at the same time as the signal on the scope. Note that the
Predriver tuning is quite broad. Once the peak is found using the
Predriver tune, adjust L1 slightly off the peak on the inductive
side (Counter-clockwise) for more efficient operation. Now
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
adjust the Predriver Level control R1 (near L1) for a scope
reading of 23Vp-p drive signal or as high as it will go. Note that
if the transmitter is at the high end of the band R1 may not be in
circuit if A14J15 on the Driver Combiner/Motherboard is in
position 1-3. It would be advisable to also measure the drive level
at right hand side of CR4 on Driver section 1 along with these
same points on the other two Driver modules. The drive level
should be within +/- 2Vp-p of each other. Note however that the
Driver section 3B drive level (right hand side of CR4) could be
as much as +/-5Vp-p different from the others due to its being
used as a neutralization amp. Its level however should be between 15Vp-p and 25Vp-p. The Predriver tune and Predriver
level should not require any further adjustment so both controls
can now be locked down.
Depress the LOW power on button and note that the high voltage
comes up as indicated on the front panel multimeter but no RF
power or PA current is indicated. With the scope DC coupled
note that an RF sine wave is now displayed on the scope. The
wave form should normally measure from 22 to 25Vp-p and it
should be centered on the 0.0VDC line of the scope. The drive
level may be lower than 20Vp-p at this time. If the wave form
falls totally below the 0.0VDC line of the scope, the Step 1
Amplifier is turned off. See Figures 5-10 and 5-11 for drive
wave forms.
5.9.6 RF Driver Adjustments
The following procedures are used to set the Driver Tuning,
Driver Amplitude, with instructions on measuring Drive amplitude and phasing.
To turn on an amplifier first make sure that the PA TURN-OFF
switch on the Controller board is set to the PA-ON position. Next
depress the RAISE button until the desired amplifier turns on as
indicated by the correct drive wave form. Note that at 0 kW
output no Big Step amps are on. As the power is raised the big
steps will successively turn on to increase the power output.
There are 42 Big Step Amplifiers, but even at 10 kW of carrier
power only Big Step Amplifiers 1 through 18 will be turned on.
Therefore holding the raise button will only turn on up to Step
18. To turn on any higher steps these must be manually turned
on using the FlexPatch feature on the Modulation Encoder
board A36. This feature will be covered later.
WARNING
ENSURE ALL POWER IS REMOVED FROM TRANSMITTER AND
THAT GROUNDING STICK HAS BEEN USED TO DISCHARGE
ANY RESIDUAL POTENTIAL WHERE POWER HAS BEEN APPLIED BEFORE PERFORMING THE FOLLOWING STEPS.
Preset the Driver Supply regulator as follows. Locate the access
holes for the Driver Supply regulator adjustments, which are
located immediately above the Oscillator board. Through these
access holes switch the Loop Select switch A22S1 to the OPEN
position (UP). Adjust both the Open Loop adjustment A22R2
and the Closed Loop adjustment A22R12 fully counter-clockwise. Connect a jumper on the LED board from A32CR10 anode
to A32CR11 anode. This will temporarily defeat the Under drive
and Overdrive overloads.
To remove the Supply voltage from the RF Amps first remove
all primary power from the transmitter. Open the front door to
the Power Supply cabinet and locate the Fuse Board A24 on the
left hand hall of the Power Supply compartment. Now remove
fuses F1 through F7. Note that F1 and F3 are not the same value
as the others. Close the Power Supply cabinet and now open the
inner front door exposing the RF Amplifiers. Locate RF Amplifier Step 1 (bottom left RF Amp). Connect a X10 scope probe to
the left hand side of CR3 which is located in front of the heat
sink. Connect the probe such that the lead can be safely routed
out the interlocked door once it is shut, and the probe will not
interfere with the closing of the inner door. Connect the ground
clip of the probe to the edge of the front of the RF amp card on
either side of the round hole in the front middle of the card. Note
that this is the ground plane for the RF Amplifier. Connect the
probe to the scope set up to measure an RF wave form at
approximately 24Vp-p. Close the inner front door of the RF
compartment and apply primary power. NOTE: A X10 SCOPE
PROBE MUST BE USED. ALSO ENSURE THAT THE
SCOPE CASE IS PROPERLY GROUNDED.
03/16/2009
NOTE
When measuring RF Amplifier drive amplitudes or phasing, the
amplifier to be measured must be turned on to give a correct
drive measurement. The drive wave form of an “OFF” amplifier
will be below 0.0VDC and the peaks will probably be clipped
The RF Multimeter should now indicate from 1 to 3 Amps on
the DRIVER I position and both DRIVER SECT.1A and
DRIVER SECT.1B should indicate 0.0VDC. The scope should
show an RF drive signal from 10 to 25Vp-p on the Step 1
Amplifier. Adjust the DRIVER TUNING control L2 for maximum drive signal as indicated on the scope display. Also note
the DRIVER I current reading will increase as the Drive wave
form increases. The Driver tuning is quite broad and it may take
many turns to obtain resonance as indicated by maximum drive
signal. Peak RF drive may occur during 1 to 5 turns of L2.
Adjust the OPEN LOOP adjustment A22R2 on the Driver Supply Regulator clockwise. Monitor both the drive wave form on
the scope and the DRIVER SECT. 1A voltage on the multimeter.
As A22R2 is adjusted note that the drive will increase along with
the voltage on the multimeter. Adjust A22R2 until the drive level
reaches 24Vp-p on the scope or the DRIVER SECT.1A voltage
reaches 100V. In either case now readjust the Driver Tuning L2
for peak drive signal. If 24Vp-p drive is indicated on the scope
and the DRIVER SECT.1A voltage is between 40 and 95VDC
continue on to “Closed LOOP Adjustment.”
To obtain an RF drive level of 24Vp-p on the RF amp, if the
DRIVER SECT.1A voltage is below 40V or over 95VDC, first
check to make sure that the Driver Tuning is adjusted for a peak
output. It would also be advisable to check the drive level on
another RF amp module such as Step 2 or Step 3. Normally the
drive level from module to module should not vary more than
+/-2Vp-p. If all these conditions are correct then the transformer
outputs of the Driver amplifiers must be changed. If the DRIVER
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-17
SECT.1A voltage is below 40VDC, this indicates that the Driver
outputs must be decreased. Note the settings of the jumpers
J17-J22 on the Driver Combiner/Motherboard. Looking at Figure 5-9, determine which combination which give the next
lowest output from the driver stage. If the DRIVER SECT.1A
voltage is higher than 95VDC, determine which combination of
jumpers would give the next highest output. Note that J17, J19
and J21 must all be set to the same tap settings as well as J18,
J20 and J22. Failure to do this will cause unequal loading of the
RF Driver amplifiers and possible premature failure.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
After changing the jumpers on the Driver Combiner/Motherboard, operate the transmitter again and adjust A22R2 so the RF
drive level on the RF amp is 24Vp-p. The DRIVER SECT.1A
voltage should be within the prescribed ranges.
Closed LOOP Adjustment. With the RF drive level at 24Vp-p,
note the DRIVER SECT. 1A voltage. Set the LOOP select switch
A22S1 on the Driver Supply regulator to the Closed position.
Now adjust A22R12 the Closed Loop adjustment, for the same
reading on the DRIVER SECT. 1A reading. The RF drive level
should again be 24Vp-p. The LOOP select switch is normally
left in the Closed position for normal operation.
WARNING
ENSURE ALL POWER IS REMOVED FROM TRANSMITTER AND
THAT GROUNDING STICK HAS BEEN USED TO DISCHARGE
ANY RESIDUAL POTENTIAL WHERE POWER HAS BEEN APPLIED BEFORE PERFORMING THE FOLLOWING STEPS.
Remove all power from the transmitter. Remove the jumper from
the LED board A32. If it is desired to set the Under drive and
Overdrive overloads see UNDER DRIVE AND OVERDRIVE
OVERLOAD SETTING.
Even though not necessary for a frequency change the RF Drive
phasing and amplitude can be checked. For Drive Level and
Phasing measurement procedures see “MEASURING RF
DRIVE LEVEL,” and “MEASURING RF DRIVE PHASING,”
in the Troubleshooting section of the manual.
Open the door to the Power supply compartment and replace
fuses F1 through F7 on the Fuse Board A24. Note: F1 and F3 is
are different fuses.
5.9.7 Initial Tuning at Low Power (1 kW)
Apply main power to the transmitter. Turn on the low voltage
and verify that all LED’s on the Mimic panel are illuminated
Green. Verify that the transmitter is properly terminated into a
Dummy load. Open the center front door and set the PA TURNOFF Switch to the PA-OFF position.
Depress the LOW power on button and verify that the high
voltage does come up, but no RF output or PA current is
5-18
indicated. Connect the Probe on the RF Multimeter to TP7 on
the Analog input board A35. Operate the multimeter select to the
PROBE +VDC (0-3) position. A half scale reading indicates
approximately an equivalent 10 kW output. Depress and hold the
Fast Power Set switch A38S4 on the Controller board. While
depressing S4 also depress the LOWER button on the front
panel. Note the voltage on the multimeter quickly dropping to
zero. Once it reaches zero release both buttons. The power output
of the transmitter is now set to zero.
Set the PA TURN-OFF switch to the PA-ON position. Depress
the RAISE button and note the power output will begin to
increase along with the PA current indication. Continue to raise
the power until the indicated output on the power meter shows
1000W. On the top of the transmitter above the Output Network
compartment locate the Bandpass Filter tune control. While
looking at the indicated power output on the front panel meter
adjust the Bandpass Tuning control for a peak in RF output
power. This setting is normally within one turn of the control
from where it was preset, using the impdeance values.
NOTE
The front panel TUNING AND LOADING controls should not be
adjusted any time during the frequency change procedure as long
as the same load termination is used.
5.9.8 Output Monitor A27 Adjustments
The Output Monitor performs three main functions:
• Forward and reflected power metering
• VSWR overload sensing
• Modulation monitor sample level adjustment
All of these functions must be calibrated for proper transmitter
operation. Set all jumpers and switches to the same position as
on the board to be replaced.
Since all of these circuits require adjustment while the transmitter output network is set to 50 + j0 Ohms, it is preferred that the
transmitter be operated into a 50 Ohm load. This procedure can
be performed into the antenna, but operating the transmitter into
a load will make measurements easier due to the lack of interference, compared to that existing on the antenna system.
5.9.8.1 DETECTOR NULL (Antenna) Adjustment
a. Set the PA TURN-OFF switch S2 on the Controller to the
OFF (up) position.
b. Depress the LOW power button. The PA Supply voltage
should be present but no power should be indicated on the
Forward Power meter.
c. Depress and hold the LOWER button for approximately
30 seconds.
d. Set the PA TURN-OFF switch S2 on the Controller to the
ON (down) position and hold the RAISE button until the
transmitter output power is approximately 500W.
e. Using a Dual trace scope, connect a 10x probe on channel
1 to TP6 and a 10x probe on channel 2 to TP5. A signal
should be visible at both TP6 and TP5.
f. While depressing momentary button switch S5, set the
Normal/Calibrate switch S8 to the Calibrate position. Note
that the signal at TP5 has dropped in amplitude.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
g. Adjust capacitor C29 for minimum signal at TP5. This
signal will contain mostly harmonics of the carrier frequency. It may be necessary to add additional capacitance
with S9-1 and S9-3 at the low end of the band or additional
inductance with S9-2 and S9-4 at the high end of the band
to achieve a minimum signal.
h. Set the Normal/Calibrate switch S8 to the Normal position
and release momentary pushbutton switch S5. Make sure
that the vertical sensitivity of both channels of the scope
are the same.
i. Connect both scope probes to TP6 to ensure that both
traces are the same amplitude. Return the other probe to
TP5.
j. Set the time base on the scope to display 2 to 3 cycles of
RF.
k. Adjust C15 to make the signal at TP6 the same amplitude
as TP5. Note that the two signals are probably not in phase
with each other. See Figure 5-12.
l. Using a non-inductive tuning tool, adjust L12 to phase
align the two signals. It may be necessary to readjust C15
to make the two signals equal in amplitude. Note that it
may not be possible to get both signals equal in amplitude
using C15 until some adjustment of L12 is made.
m. If, by adjusting L12, it is not possible to align the two
signals in phase, select a different value of capacitance
across L12 by switching in one or more sections of S6 then
readjusting L12 for an in phase signal.
n. Note that as the amplitude and phase of the two signals are
matched, the meter reading in the DETECTOR NULL
(Antenna) position will null. Fine adjustments of these
controls will be made at full power once the Bandpass
Filter controls are set.
5.9.8.2 DETECTOR NULL (Bandpass Filter) Adjustment
a. Using a Dual trace scope connect a 10x probe from channel 1 to TP10 on the Output Monitor. Connect a 10x probe
from channel 2 to TP1. A signal should be visible at both
TP1 and TP10.
b. While depressing the momentary pushbutton switch S5,
set the Normal/Calibrate switch S8 to the Calibrate position. Note that the signal at TP10 has dropped in amplitude.
c. Adjust capacitor C21 for minimum signal at TP10. Also
note that the minimum residual signal will contain mostly
harmonics of the carrier frequency.
d. If a minimum cannot be achieved due to the capacitor C21
running out of range, use S1 to select a different value of
capacitance (C3 or C5), or a different value of inductance
(L2 or L3) to null out the signal at TP1. Note that some
frequencies may not require any added reactance. Normally capacitance is added at the low end of the frequency
band and inductance is added at the high end of the band.
e. Set the Normal/Calibrate switch S8 to the Normal position,
and release momentary pushbutton switch S5. Make sure
that the vertical sensitivity of both channels of the scope
is the same.
03/16/2009
f. Set the time base on the scope to display 2 to 3 cycles of
RF.
g. Adjust C16 to make the signal at TP1 the same amplitude
as TP10, and also note that it may not be possible to get
both signals equal in amplitude using C16 until some
adjustment of L5 through L8 (selected by S7) is made.
Capacitance can be added with S2 if the signal cannot by
nulled with C16.
h. Note that the two signals are probably not in phase with
each other. See Figure 5-12.
i. Using a non-inductive tuning tool, adjust L5 through L8,
depending on which one is selected by the DIP switch S7,
to phase align the two signals. It may be necessary to
readjust C16 to make the two signals equal in amplitude.
j. If, by adjusting the selected variable inductor L5-L8, is not
possible to align the two signals in phase, select another
value of variable inductance with S7. Note that as the
amplitude and phase of the two signals are matched the
DETECTOR NULL (Filter) position on the Multimeter
will also null.
5.9.8.3 Fine Tuning
a. With the transmitter operating at 500W, both the DETECTOR NULL (Antenna) and the DETECTOR NULL (Filter) positions on the front panel multimeter should indicate
near zero.
b. To prevent possible modulation monitor damage, turn
both the MEDIUM and HIGH power modulation monitor
adjustment controls R7 and R8 full CCW.
c. Bring the transmitter to 10 kW and note the DETECTOR
NULL (Antenna) position on the multimeter. If the reading
is now above zero, null this reading using both C15 and
L12.
d. Note the DETECTOR NULL (Filter) indication on the
multimeter. If it is above zero, null it using C16 and L5
through L8, depending on what was selected by S7. The
final adjustments will be made into the antenna at full
operating power.
e. Modulate the transmitter with a 10 kHz tone, or one which
causes the greatest upward deflection on the DETECTOR
NULL (Antenna) meter reading, and recheck nulls.
f. Use a digital voltmeter or a dc coupled oscilloscope and
adjust for minimum voltage at TP8 and TP9 with reference
to ground.
5.9.8.4 Trip Threshold Adjustment
The overload settings for the Antenna and Bandpass circuit are
listed in the Factory Test Data sheet. After the replacement board
has been installed, set the overload settings as follows:
5.9.8.4.1
Antenna VSWR overload
a. Turn on the Low Voltage at CB1 and CB2.
b. Connect a voltmeter to TP4.
c. Adjust R24 until the voltage matches the Factory Test Data
sheet.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-19
If the Factory Test Data sheet is unavailable or if it is necessary
to verify the original overload setting, use the following procedure:
a. Verify that the DETECTOR NULL (Antenna) reading on
the front panel multimeter is nulled (zero) at full power.
b. Press LOW power, and adjust the RF output for 600W on
DX-10 or 900W on DX-15.
c. Depress the OFF button.
WARNING
ENSURE ALL PRIMARY AC VOLTAGE HAS BEEN REMOVED
FROM TRANSMITTER AND A GROUNDING STICK IS USED TO
GROUND ALL POINTS WHERE AC OR RF POWER HAS BEEN
APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
d. Remove the rear panels from the Output Network Compartment.
e. Reverse the Antenna VSWR current sample by placing P1
from 1-2 and P2 from 2-3 on the Output Sample Board.
f. Replace the rear panels on the Output Network Compartment.
g. Restore primary ac voltage at the main breaker.
h. Depress the LOW power button.
i. Switch the front panel multimeter to the DETECTOR
NULL (Antenna) position. Note that the meter reads upscale.
j. Adjust R24 until the transmitter indicates an ANTENNA
VSWR fault condition on the ColorStat panel.
k. Turn the transmitter OFF.
WARNING
ENSURE ALL PRIMARY AC VOLTAGE HAS BEEN REMOVED
FROM TRANSMITTER AND A GROUNDING STICK IS USED TO
GROUND ALL POINTS WHERE AC OR RF POWER HAS BEEN
APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
l. Remove the rear panels from the Output Network Compartment.
m. Place P1 and P2 on the Output Sample Board in the Normal
position.
n. Replace the rear panels on the Output Network Compartment.
5.9.8.4.2
Bandpass VSWR Overload
a. Turn on the Low Voltage at CB1 and CB2.
b. Connect a voltmeter to TP3.
c. Adjust R23 until the voltage matches the factory test data.
5.9.8.5 Forward/Reflected Power Adjustments C6 and C40
a. With the transmitter operating at 10 kW and no modulation, read the Reflected power indication on the front panel
meter.
5-20
b. Adjust C40, Reflected Balance control, to null the meter
indication. Note that C30 is added by P2 at the low end of
the band to allow the meter indication to null.
c. Depress the OFF button.
d. Locate P1 and P3 on the Output Monitor. Move both
jumper plugs from position 1-2 to position 1-3.
e. Turn the transmitter back on at full power. Note that the
Reflected meter position now indicates forward power and
the Forward meter position now indicates reflected power.
f. Operate the Forward/Reflected meter switch to the Forward power position. Adjust C6 to null this indication.
g. Depress the Off button and move jumpers P1 and P2 to
position 1-2.
5.9.8.6 Modulation Monitor Sample Adjustments
Refer to the Initial Turn-On procedure in SECTION II, Installation/Initial Turn-On, for the procedure to set the Modulation
monitor sample adjustments.
5.9.9 Final Initial tuning at low Power
Depress the transmitter RAISE button until the transmitter output power indicates 1000W. Adjust the Bandpass Tuning control
C101 for peak output power. Peak output may occur at as many
as 5 turns at the low end of the band and as little as 1 turn at the
high end. It is preferred to leave the tuning slightly on the
inductive side of resonance for optimum efficiency and performance. The inductive side of resonance is indicated by a faster
drop in PA current than power output when tuning the Bandpass
Tuning C101 off the power peak. Inductive side of resonance is
achieved by turning C101 counter clockwise from the point
where the power peak is found. The capacitive side of resonance
is normally indicated by a PA current that does not drop as fast
as the power when C101 is tuned off the peak. Also on the
capacitive side of resonance the RF amp temperatures will tend
to increase and PA efficiency will decrease.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Depress the OFF button, quickly remove power and open the
inner front door. Starting with RF Amplifier Step 1, feel the cases
of the two exposed MOSFET’s checking for any module that
appears to be running excessively warm. Only check modules
Steps 1-7 at this time. If any module is running hot, the Drive
amplitude and phasing of that module should be checked. For
Drive Level and Phasing measurement procedures see “MEASURING RF DRIVE LEVEL,” and “MEASURING RF DRIVE
PHASING,” in the Troubleshooting section of the manual.
5.9.9.1 Modulated B-Check
Modulate the transmitter at 1 kW with a 100Hz sine wave at
100% modulation. Connect a scope to A30TP7 on the DC
Regulator board. Displayed will be the Modulated B-wave form
similar to the one in Figure 5-13. Set the scope for 1V per
division, DC coupled and the 0.0VDC line on the top graticule,
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
since this is a wave form at a negative voltage. The positive peak
of this wave form should be from -2.2 to -2.3VDC. The negative
peak should occur between -3.0 and -4.5VDC. If the wave form
is not within these tolerances then the modulated B- adjustments
should be reset using the procedure “MODULATED B-ADJUSTMENTS.”
5.9.9.2 A to D Phasing Check
Make sure that the switches and jumpers are preset according to
the Frequency Tuning chart. Leave the transmitter at 1 kW,
modulated at 100% with the 100Hz tone. Feed the demodulated
output of the Modulation monitor in the scope. Adjust the scope
to display one cycle of audio. It may be necessary to sync the
scope to the audio generator. Expand the vertical display to view
more closely at the audio wave form. If the A to D phasing is not
set optimally then glitches or small notches may be visible in the
demodulated wave form. These glitches are normally evident
throughout the modulation cycle and can be reduced by selecting
different combinations of capacitance on the A to D board using
the selector switch A34S1. Note that the capacitor values are in
binary weighted steps therefore different combinations of capacitance can be selected. Glitches that appear on the positive
peak of audio should be concentrated on since these glitches
indicate the amount of stress on an RF amplifier and the most
amount of current is flowing through the amplifier at the modulation peaks. Note that some amount of glitching is going to be
visible at all times on the negative peak and is normal especially
at the lower power levels.
NOTE
If by adjusting the A to D phasing glitches are not removed then
they may be caused by improper Modulated B-adjustment. Return
the A to D phasing switches on the A to D board S1 to their
original positions and see paragraph entitled “MODULATED BADJUSTMENTS.”
5.9.10 Initial Tuning at High Power (10 kW)
With the transmitter operating at 1 kW unmodulated depress the
RAISE button and increase the power until 5 kW is indicated.
The PA current should be between 25 and 30 Amps. Readjust
the Bandpass tuning C101 for peak power output. If the PA
current is within the above limits again depress the RAISE button
until the transmitter power output reaches 10 kW. Adjust the
Bandpass tune again for peak power output then turn the control
slightly on the inductive side (CCW) to the point where the
power output just starts to come off the peak. The Supply Voltage
should be between 220VDC and 235VDC, with the PA current
being between 50 and 55Amps. Allow the transmitter to operate
here for 5 minutes while meter readings are taken.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Depress the OFF button, quickly remove power and open the
inner front door. Starting with RF Amplifier Step 1, feel the cases
of the two exposed MOSFET’s checking for any module that
03/16/2009
appears to be running excessively warm. Only check modules
Steps 1-20 at this time. If any module is running hot, the Drive
amplitude and phasing of that module should be checked. For
Drive Level and Phasing measurement procedures see “MEASURING RF DRIVE LEVEL,” and “MEASURING RF DRIVE
PHASING,” in the Troubleshooting section of the manual. Open
the rear panel on the Output Network compartment and feel all
connections and components for excessive heating. The most
heat will be normally felt at the low impedance, high current
points in the network which includes the output connection of
the Combiner at L101 and the front of L102 at the
L102/C101,C102 connection. If any high temperature connections are noted check those connections for proper tightness and
surface mating.
5.9.10.1 Modulated B-Check
Modulate the transmitter at 10 kW with a 100Hz sine wave at
100% modulation. Connect a scope to A30TP7 on the DC
Regulator board. Displayed will be the Modulated B-wave form
similar to the one in Figure 5-14. Set the scope for 1V per
division, DC coupled and the 0.0VDC line on the top graticule,
since this is a wave form at a negative voltage. The positive peak
of this wave form should be from -2.0 to -2.3VDC. The negative
peak should occur between -4.5 and -5.0VDC. If the wave form
is not within these tolerances then the modulated B-Adjustments
should be reset using the procedure in paragraph entitled
“MODULATED B- ADJUSTMENTS.”
5.9.10.2 A to D Phasing Check
Leave the transmitter at 10 kW modulated between 20 and 40%
with the 100Hz tone. Feed the demodulated output of the Modulation monitor to the scope. Adjust the scope to display one cycle
of audio and adjust the trigger level, horizontal position, and
vertical gain to expand the display to view the positive modulation peak. It may be necessary to sync the scope to the audio
generator. Expand the vertical display to view more closely the
audio wave form. If the A to D phasing is not set optimally then
glitches or small notches may be visible in the demodulated wave
form. If these glitches are evident throughout the modulation
cycle select different combinations of capacitance on the A to D
board using the selector switch A34S1 Glitches that appear on
the positive peak of audio should be concentrated on since these
glitches indicate the amount of stress on an RF Amplifier and the
most amount of current is flowing through the amps at the
modulation peaks. Note that some amount of glitching is going
to be visible at all times on the negative peak and is normal
especially at the lower power levels. It should not be necessary
to make large changes in capacitance from the original switch
settings. If no improvement is visible return the switches to their
original positions. Also, if too much capacitance is added it is
possible to obtain a “Conversion Error” fault.
5.9.11 Final Output Network Tap Settings
To determine the amount of loading the RF Amplifiers are
receiving, the number of amplifiers that are turned on to produce
10 kW will be measured. Normally to allow the transmitter to
operate at 11 kW with 125% positive peak modulation, Big Step
Amplifiers 1-17 must be turned on
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-21
and loaded to produce 9.07 kW of carrier power. If Steps 1-20
are turned on then the transmitter will not be able to produce
sufficient positive peak modulation for 11 kW. If only Steps 1-15
are required for 10 kW carrier then all the modules are loaded
more than originally designed for.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE MAKING ADJUSTMENTS IN THE OUTPUT NETWORK.
On the Modulation Encoder board A36 set all the switches on
S1 to the off position. Note that the power level may have
changed due to the Binary Amplifiers now being off. Hold the
RAISE or LOWER button until Big steps 1-17 are on and steps
18-42 are off. This can be determined by measuring the voltage
on the gold jumpers for each step on the Modulation Encoder
board. An “ON” Amplifier will have a +5VDC encoder signal,
while an “OFF” amplifier will have a 0VDC signal. Note that
because the binary’s are off the power output will only jump in
BIG STEPS. Only the Big Step amplifiers are on at this time.
Connect a scope set to measure 5VDC to the gold jumper P3 1-2
on the Modulation Encoder board A36. This is the jumper for
Step 9. The scope should now indicate 5VDC which means that
Big Step 9 is being told to turn on. Now connect the scope to the
jumpers for Big Steps 15-19. Note at which step the DC voltage
is zero. This indicates an off amplifier. Depress the RAISE or
LOWER button until Step 17 is on and Step 18 is off. The power
output at this time should be approximately 9 kW. If the power
is lower then the RF Amplifiers need to be loaded heavier by
moving the L102/C101,C102 tap towards the grounded end of
L102 (front). If the power output is higher than 9 kW, then the
loading must be decreased by moving the tap away from ground
on L102. Note that the tap on the coil should only be moved in
1/2" increments at a time, checking the loading each time by
raising and lowering the power and seeing which step produces
approximately 10 kW output.
5.9.11.1 Bandpass Filter Response
The L102/L103 tap determines the response of the Bandpass
filter. If the response was set during the initial output network
tune-up it should not require readjustment. To check the response, operate the transmitter at 1 kW and modulate 50% with
a 1 kHz sine wave, to set a reference for audio frequency
response. Now modulate the transmitter at 10 kHz and 20 kHz
and measure the audio frequency response. Response should be
-0.6 +/-0.2 dB at 10 kHz and -2.2 dB +/-0.2 dB at 20 kHz. If the
audio frequency response is down more than 2.4 dB at 20 kHz,
the filter response is too narrow and the L102/L103 tap should
be moved closer to the L102/C101-C102 tap. If the response is
less than 2.0 dB down at 20 kHz the filter response is too broad
and the L102/L103 tap should be moved away from the
L012/C101-C102 tap. Move the tap in 1/2" increments, checking
the performance each time.
5-22
5.9.12 Output Monitor A27 Final Adjustments
5.9.12.1 Antenna and Bandpass Filter Final Adjustments
Now with the transmitter operating at 10 kW forward power,
note that both the Antenna Null and Bandpass Filter Null positions on the front panel multimeter should indicate near zero. If
the Antenna Null reading is above zero, null this reading using
both A27C15 and A27L4 on the Output Monitor board. Now
note the Bandpass Filter Null indication on the multimeter. If it
is not zero, null it using A27C29 and A27L12 through A27L15,
depending on what was selected by S6.
5.9.12.2 Forward and Reflected Power Null Adjustments
A27C3 and A27C4
With the transmitter operating at 10 kW with no modulation,
select the Reflected power indication on the front panel meter
switch S8. Adjust A27C4 Reflected Balance control to null the
meter indication to zero. Note that A27C49 is added at the low
end of the band to allow the meter indication to null. Depress the
front panel OFF button to turn off the transmitter high voltage.
Locate P1 and P2 on the Output Monitor board. Move the jumper
plugs from position 1-2 to position 1-3 on both plugs. Turn the
transmitter back on to 10 kW output. Note that the Reflected
power meter position indicates forward power. Operate the
Forward/Reflected meter switch to the Forward power position.
Note that it now indicates reflected power. Adjust A27C3 to null
out this indication to zero. Depress the OFF button and move the
jumpers on P1 and P2 to position 1-2.
5.9.12.3 Modulation Monitor Sample Adjustments
For the setup procedure on setting the Modulation monitor
sample adjustments, see the Output Monitor board, Section H.
5.9.12.4 Oscillator Sync Adjustment A17S1 and A17L4
The Oscillator Sync adjustment is critical to the proper operation
of the VSWR circuitry in the transmitter. If this circuit is not set
properly, damage to the RF Amplifiers could result during a
VSWR condition.
Using a dual trace scope connect channel 1 to TP5 on the
oscillator board and channel 2 to TP4 on the oscillator board.
Sync the scope to channel 1. Apply the low voltage and note a
5Vp-p square wave at the RF carrier frequency on scope channel
1. Set the sweep speed on the scope to display one or two cycles
of RF. Operate the transmitter at 10 kW with no modulation. At
this time note that channel 2 will also have a 5Vp-p square wave
displayed. If the positive going edges of the two wave forms are
lined up, no further adjustments are required. If the trace on
channel two is not aligned in phase, adjust L4 to make them line
up as seen in Figure 5-16.
If by adjusting L4 the two wave forms will not line up, then
different combinations of capacitance as selected by S1 can be
switched in to provide various amounts of phase shift. If it
appears that the two signals are 180 degrees apart then the plug
P3 can be reversed at J3. This should not be the case if the board
is simply being replaced assuming the plug position was noted
before removal. Note that when switching in different values of
capacitance, try to use the least amount of capacitance (S1-1, 2,
and 3) to achieve phase alignment of the two signals. If too much
capacitance is used there may not be enough signal input to
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
produce a signal at TP4. Operate the transmitter at 1 kW and note
that the two signals may not be as well aligned as at 10 kW but
make sure there is still a signal at TP4.
RF Amplifier transition occurs at the first large division on the
right, this amplifier is operating at 4 degrees lagging from the
reference.
5.9.13 Completion of Basic Frequency Change of
Check the drain of Q3 on Big Step 1-3 to verify that they are all
within 2 degrees of each other. Check the drain of Q3 on the
Binary Amplifier B-7 (top left module). Note that Q3 is now the
right hand MOSFET when viewing the module from the front.
Operate the transmitter again at 5 kW. If no wave form appears,
then depress the RAISE or LOWER button until this step turns
on. Remember as the power is changed the Binary’s are turning
on and off at different rates. The vertical sensitivity of the scope
can be increased to view the Binary’s since B-7 through B10
operate at 1/2 the supply voltage. If the Phasing of B-7 is within
2 to 3 degrees move to B-8. If it is greater, then the tap on L1 can
be changed to put the B-7 amplifier in phase. Note that typically
more of the inductor will be shorted out for the Binary’s than for
the Big Steps. Do not reduce Efficiency coil turns to less than
1/2 of the given Frequency determined value.
DX-10
This completes all the basic requirements in changing the frequency of the DX-10. At this time the transmitter adjustments
critical to reliability and basic performance have been addressed.
The following procedures are given to allow the transmitter to
be checked and adjusted for optimum performance.
5.9.13.1 Binary Amplifier Phase Alignment
The Binary RF Amplifiers B7-B12 are designed to produce
output RF voltages less that that of the big step amplifiers. This
is performed by reducing their supply voltage and changing their
output transformer turns ratio. This causes the Binary amplifiers
to not always operate at the same output phase of RF as the Big
Steps. This phase difference can be anywhere from 0 to 30
degrees. Because the Binary’s operate at lower powers this
situation does not affect reliability but can have an effect on the
amount of IPM products the transmitter produces. Therefore
mainly this Binary Amplifier Phase alignment is performed to
achieve optimum stereo performance. This alignment is performed by measuring the phase difference between the Big Step
Amplifiers and the Binary’s at the output of each amplifier and
adjusting the tap on the Efficiency coil for that amplifier to
within 2 degrees of the big steps.
WARNING
ENSURE ALL POWER IS REMOVED FROM TRANSMITTER AND
THAT GROUNDING STICK HAS BEEN USED TO DISCHARGE
ANY RESIDUAL POTENTIAL WHERE POWER HAS BEEN APPLIED ANY TIME THE INNER FRONT DOOR IS OPENED TO
ACCESS THE RF AMPLIFIER MODULES.
Normally the taps on the Efficiency coils for the Binary amps
should already be preset to some value per the frequency tuning
chart. Open the inner front door of the transmitter and connect a
X10 scope probe to the drain of Q3 on the Step 1 RF amp. The
drain is the center pin of Q3 which is the left hand MOSFET
front the heat sink. Route the X10 probe and cable on the scope
such that the inner front door can be closed. NOTE: A X10
SCOPE PROBE MUST BE USED. ALSO ENSURE THAT
THE SCOPE CASE IS PROPERLY GROUNDED. Set the
scope on AC coupled, 50V per division with trace centered on
the screen. Connect the external sync of the scope to J5 on the
oscillator board and make sure the scope sync is set to External.
Operate the transmitter at 5 kW with no modulation. Adjust the
Horizontal vernier on the scope so that one full RF cycle occupies 9 divisions on the screen. Each division now equals 40
degrees of phase shift. Using the Horizontal positioning and
triggering level on the scope place the transition time of the scope
on the center vertical line of the screen. Increase the vertical
sensitivity of the scope to expand the wave form. Switch the
scope to the X10 position and readjust the horizontal position so
that the RF transition again crosses the center line of the scope.
This will be the reference for the phase measurements. If another
03/16/2009
Continue to check the phasing on the remaining binary’s. Note
that the amount of active turns on the Efficiency coils will tend
to be less on the smaller binary steps. B-11 and B-12 only operate
on a 30VDC supply and therefore will not be able to phase align
to 0 degrees as the other binary’s would. For B-11 and B-12 set
the coil taps for 1/2 of the normal FD value on the Big Steps and
accept the amount of drive phase error (typically 5 to 15 degrees).
This error is not critical since these two steps operate at 1/32 and
1/64th of the amplitude of a big step.
5.9.14 Binary Amplitude Alignment
The output of the Binary Amplifiers can very from frequency to
frequency. To optimize the linearity of the modulation signal,
the output amplitude of the Binary amplifiers can be varied in
5% increments. To check the Binary alignment, operate the
transmitter at 1 kW output with 100Hz triangle modulation.
Triangle or ramp modulation must be used for this procedure.
On the scope display the demodulated output of the modulation
monitor. Use the external sync on the scope connected to the
output of the generator. Expand the vertical and horizontal
display to view the positive going portion of the ramp. Connect
the other channel of the scope to the Modulation Encoder gold
jumper for Step 5. Raise or lower the modulation until a transition from 0V to 5V can be seen on the Step 5 display. From this
display it is possible to see at which point in the modulation ramp
Step 5 is being turned on. Now look at the Modulation Encoder
signal for Step 6. Raise and lower the modulation until it can be
seen turning on. It may also be noted where a big step turns on
by a small glitch that may appear in the demodulated wave form.
See Figure 5-17. By both making small changes in power level
and modulation level it should be possible to display the demodulated ramp between two big steps. This is the area to look
at for binary alignment. If the binary alignment is proper, the
transitions between big steps will be smooth. If, for instance, the
1/2 Step B-7 amplitude was too low you will see a glitch halfway
between Step 5 and Step 6. This is the half step transition. You
may also see that there is now a glitch at Step 5 and Step 6 also.
See Figure 5-18.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-23
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Determining which binary step amplitude is not lining up with
the others can take some trial and error. To change the binary
amplitude for the 1/2 Step for example, open the inner front door
and remove the 1/2 Step Amplifier B-7 and the Big Step Amplifier 1. Looking through the slots of the removed amps J30 can
be seen on the motherboard in the center. Move the plug to the
next desired position. Reinsert the modules and check the ramp
linearity. Repeat for all Binary Steps B-7 through B-10 if necessary. B-11 and B-12 do not have amplitude adjustments. Note
that the ramp may not appear to be perfect even at what appears
to be optimum binary alignment, but remember that the displayed ramp is at LOW power at around 10% modulation.
5.9.15 Neutralization Adjustment
The purpose of the neutralization circuit is to cancel out any
feed-through signal that occurs due to the gate to drain capacitance that exists in the RF Amplifier MOSFET’s. Normally this
feed through signal does not affect transmitter operation, except
when the transmitter is to be operated as a stereo transmitter.
Excessive feed through will tend to degrade the stereo performance in terms of Incidental Phase Modulation (IPM). Again this
procedure is not required but is recommended for stereo operation. If the transmitter frequency determined jumpers were set
properly on the Driver Combiner board, the neutralization is
probably very close.
Operate the transmitter at about 500W RF output. Modulate to
110% with a 100Hz sine wave. Expand the negative modulation
cut-off area on the scope in both horizontal and vertical directions to observe the amount of carrier feed-through. Note the
amplitude of this feed through. Depress the OFF button; remove
the low voltage with switch S11.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Connect a scope lead to the right hand side of CR4 on the
neutralization amplifier which is Driver Section 3B. Apply low
voltage by switching S11 and measure the amount of drive to
this amplifier. It should be between 20 and 30Vp-p.
Again remove all power and open the center rear door. Jumpers
J25 through J29 will change the amount of capacitance in the
neutralization circuit. These values are binary weighted and
therefore different combinations of jumpers will make small
jumps in capacitance. J30 will change the amount of inductance
in the neutralizing circuit depending on how much coil is put in
circuit. J23 selects the amount of neutralization signal to be fed
into the Combiner.
5-24
Whenever any jumper changes are made to the Neutralization
circuit, the drive level on the neutralization amplifier should be
checked to ensure that it is between 20 and 30Vp-p. If it is not
in this range do not apply high voltage to the transmitter or
damage to the neutralization amplifier could occur. Choose the
neutralization jumpers such as to produce minimum feed
through signal
5.9.16 Overall Modulated B- Adjustment
This procedure assumes that the Modulated B- circuit is currently working but may be outside the limits mentioned in the
paragraph “Modulated B-Check”. If either the Analog Input A35
or DC Regulator board A30 has been changed, first perform the
initial setup on the board as indicated in the REPLACING
BOARDS paragraph of this section.
The end result of the Modulated B- adjustments is to produce a
demodulated audio signal with as minimum amount of glitching
as possible. To do this the following controls are used. Note that
when setting up these controls the transmitter is operated at 10
kW with a 100Hz sine wave modulating at 100%.
5.9.16.1 Gain Adjust A35R85
Normally this is set up for maximum gain which is fully Clockwise.
5.9.16.2 Offset Adjustment A35R84
This adjustment will affect the positive peak of the Modulated
B- signal. This control is set just to the point where the wave
form will clip and then is backed off so that clipping doesn’t
occur. If too much offset is used then glitching can occur on the
Negative peak of the demodulated audio wave form.
NOTE
Remember that the POSITIVE PEAK of the MODULATED Bwave form actually corresponds to the NEGATIVE PEAK of the
MODULATION ENVELOPE. If an adjustment is made to the
Positive going B- wave form at TP7 then look at the Negative
demodulated audio peak for glitches.
5.9.16.3 Modulated B- Level A30R38 DC Regulator board
With just the low voltage on this control is adjusted for a DC
voltage at A30TP7 of -2.0 to -2.3VDC. This control works in
conjunction with the Offset control to reduce glitches on the
modulation negative peaks. This control will however affect the
glitches on the positive peaks if set too low.
NOTE
When looking at the demodulated audio negative peaks, some
glitches will be noticed especially at the lower power levels.
Some of this is normal and cannot be removed by Modulated Badjustments.
5.9.16.4 Clip Adjustment A30R39 DC Regulator
This control is normally set for a maximum negative excursion
of -5.0VDC of the Modulated B-wave form while the transmitter
is at 10 kW with 140% positive modulation at 100Hz. Typically
this voltage is less than -5.0VDC at 100% modulation. Any
further negative excursion could cause amplifier damage due to
the peak RF amps not being able to turn off properly.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
5.9.17 Other Adjustments
These adjustments should normally not change during a frequency change, but it is advisable to check their setting for
optimum transmitter performance.
This sets the proper audio modulation level into the transmitter.
See paragraph on the Analog Input board replacement.
5.10.1 Interfacing For Stereo
Connect the RF output of the stereo exciter through a BNC cable
to A17J2 on the Oscillator board. Move Jumper P3 to position
1-2. This enables the external drive input. Move A17P5 to
position 1-2 for most TTL exciter RF outputs. This a 20k Ohm
termination. Move A17P5 to 1-3 for a 50 Ohm termination
needed for higher level exciter RF outputs.
5.9.17.2 Offset Adjust A34R75
5.10.2 Adjustments that affect IPM:
5.9.17.1 Audio Gain Adjust A35R15
This control adjusts the Modulation tracking of the transmitter
or in other words how equally it will modulate at different power
levels. See paragraph on the A to D board replacement procedure.
5.10.2.1 RF Driver Tune L2
This control smooths out the small modulation steps caused by
the Digital Modulation process. See paragraph on the Analog
Input board replacement.
This control is normally set for a dip in the DRIVER SECT.1A
voltage on the RF Multimeter when the Driver regulator is in the
CLOSED LOOP position. The best IPM also occurs in this
region. Normally the Driver tune is very broad and normally will
not cause any problems if adjusted though a reasonable range.
Adjusting the control on the capacitive side of resonance (CW)
will cause the Drivers to operate less efficiently.
5.9.17.4 Envelope Error Fault Adjusts A32R65 and A32R68
5.10.2.2 Bandpass Tuning C101
These two controls set up the error detection circuitry for indicating when an RF Amplifier fails. See paragraph on the LED
board replacement.
The Bandpass tuning is the only other control that will have any
noticeable effect on the IPM of the DX-10. Normally the Bandpass tuning is adjusted for Peak RF output out of the transmitter
as indicated on the power meter. From there the control is
adjusted slightly off the peak on the inductive side. This is the
same as turning the control counterclockwise. This setting is
typically optimum for Efficiency, IPM and Mono THD and
IMD. The Bandpass tune can be adjusted while the transmitter
is on and modulating.
5.9.17.3 Dither Adjust A35R43
5.10 AM Stereo Installation and Tuning
Hints
The DX-10 is a stereo ready transmitter in terms of interfacing
the stereo exciter into it. The most difficult part of making a
transmitter stereo ready is the adjustments for minimizing the
IQM, increasing RF bandwidth, and reducing L-R noise. All
these were taken into consideration in the design of the DX-10
thus producing a transmitter which essentially requires NO
compromise of Efficiency, Tuning, or Mono performance to
Obtain the best stereo performance. In fact when most controls
are set for best stereo performance, the other performance areas
are also optimized.
03/16/2009
CAUTION
THE BANDPASS TUNING CONTROL SHOULD NOT BE ADJUSTED
MORE THAN 500W OFF OF THE POWER PEAK. MOST EFFICIENT
OPERATION OCCURS AT OR NEAR THE POWER PEAK. TUNING
OFF THE POWER PEAK IN THE CAPACITIVE DIRECTION COULD
CAUSE EXCESSIVE OVERHEATING OF THE RF AMPLIFIER
MODULES.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-25
Figure 5-8
Predriver Input drive wave form, measured at the Anode of CR7 or CR8
on Predriver Module.(5 Vp-p per division)
Figure 5-9
Driver Transformer tap setting diagram
A14T7, T10 and T11.
5-26
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 5-10
RF Drive wave form at RF Amplifier, gate of Q3 (Anode of CR7).
RF Amplifier turned “OFF”. (5 Vp-p per division)
Figure 5-11
RF Drive wave form at RF Amplifier, Gate of Q3 (Anode of CR7).
RF Amplifier turned “ON”. (5 Vp-p per division)
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-27
Figure 5-12
Antenna VSWR Detector voltage and current samples as measured at Output Monitor
A27TP1 and TP2. Also typical of Bandpass filter samples.
5-28
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 5-13
Modulated B- wave form at DC Regulator A30TP7. 1kw operation with 100 Hz
100% modulation. 1 V per division, 0.0 VDC at top line.
Figure 5-14
Modulated B- wave form at DC Regulator A30TP7. 10kw operation with 100 Hz,
100% modulation. 1 V per division, 0.0 VDC at top line.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-29
Figure 5-15
Oscillator sync samples at Oscillator A17TP4 and TP5. Transmitter operating at
10kw with no modulation. The two samples are not in phase. (1V per division)
Figure 5-16
Oscillator sync samples at Oscillator A17TP4 and TP5. Transmitter operating at
10kw with no modulation. The two samples are in phase. (1 V per division)
5-30
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 5-17
Demodulated audio. Transmitter operating at 1kw with 100 Hz, approximately 10% triangle modulation.
Top trace-demodulated audio.
Bottom trace-Modulation Encoder wave form of Step 6.
Good Binary alignment shown.
Figure 5-18
Demodulated audio. Transmitter operating at 1kw with 100Hz, approximately 10% triangle modulation.
Top trace-Demodulated audio.
Bottom trace-Modulation Encoder wave form of Step 6.
Insufficient 1/2 Binary Step output shown.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
5-31
5-32
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section VI
Troubleshooting
6.1 Introduction
This section of the technical manual will contain troubleshooting
procedures for the DX-10 AM TRANSMITTER.
This troubleshooting section will be sectioned such that the most
likely problems that could cause an OFF AIR situation will be
covered first. This will include a listing of possible situations and
the possible problems. The front panel FAULT indicators including overloads and interlocks will also be discussed. This
section is a troubleshooting guide for the transmitter as a system.
If the problem is isolated to a particular board then the troubleshooting for that board will be covered in the section of the
manual for that particular board.
In general this section contains techniques and guidelines to
assist the engineer in isolating the problem more quickly. It is
assumed that the engineer using this section of the manual has
the proper test equipment available and has a good working
knowledge of the DX-10 Transmitter obtained by careful study
of the Theory of Operation.
The following is a table of contents for the Troubleshooting
section to allow quicker access to a particular area of information
on a certain problem.
6.2 Initial Troubleshooting, Critical OFF-
AIR Situations
The following paragraphs are a guide to the most basic problems
and will hopefully guide the technician to more extensive levels
of troubleshooting as it become necessary.
6.2.1 Symptom: Transmitter will Not Turn On-No
Front Panel Indicators are Illuminated
Possible Causes
6.2.1.1 Loss of AC Power
If no indicators on the front panel of the transmitter are illuminated, open the front door and see if any LED’s are illuminated
on the A to D board or the Modulation Encoder Board. If these
are not on this indicates that the Low voltage supply is inoperative. On the front panel multimeter check for proper indications
on the +22V and +8V supply positions. Make sure that the Low
voltage power switch S11 (located below the Oscillator board)
is set to the ON position. Check the Low voltage supply circuit
breakers CB1 and CB2 next to S11. The white button will
protrude out on an open breaker. Finally check the AC main
power to the transmitter to ensure that the Fuses or Circuit
breaker has not opened.
6.2.1.2 Loss of +5V Supply on LED board
If the front panel LED’s are not illuminated and the LED’s on
the A to D Converter and Modulation Encoder are illuminated,
then this indicates a problem with the Controller/LED board. The
03/16/2009
+5V supply for the LED board is developed on the controller
board. Check for +5V at the Controller board on TP1. DS1 on
the Controller board will illuminate any time any of the three
regulators on the controller fails.
6.2.1.3 Loose Ribbon or Amp Connectors
Check for loose or improperly installed connectors on both the
LED and Controller boards. Also check the connectors on the
Power Distribution board A39.
NOTE
Do not remove any plugs with the power on.
6.2.2 Symptom: Transmitter Will Not Turn ON-All
Front Panel Indicators Are Illuminated Green.
Possible Causes
Any time the transmitter will not turn on and all the front panel
indicators are Green, this indicates a problem specifically with
the contactor turn on logic, contactor drive circuits, or the
contactors themselves.
6.2.2.1 +5V “B” Circuit Not Up To Operating Voltage
If the +5B supply which uses the 1F capacitor backup is not
operational then the transmitter will not turn on. If the transmitter
does not have a good set of backup batteries installed BT1-BT3,
and the transmitter has been off for more than two hours, the
backup capacitor C94 requires approximately 1 minute to recharge which keeps the transmitter from turning on. Measure
TP4 on the Controller board and verify that the +5B voltage is
present. If it is not, troubleshoot the +5B supply.
6.2.2.2 Contactor Turn On Logic
On The Controller Board, measure the voltage at the collector of
Q5 on the Controller board. It should be approximately
+15VDC. While monitoring this voltage, depress the LOW
power on button. The voltage should drop to near 0VDC for
approximately 1 second. If it doesn’t, troubleshoot the Controller
contactor drive logic. If the voltage does drop down but the step
start contactor does not energize, the problem is in the contactor
drive circuits discussed next.
6.2.2.3 Contactor Drive Circuitry
On The DC Regulator Board, measure the AC voltage from the
DC Regulator A30F2 and Wire 42 on the contactor K1. The
voltage should be approximately 24VAC. Check F2 for an open.
Check U2 and Q3 on the DC Regulator, which are the drive
components for the step start contactor K1.
6.2.2.4 Open Contactor Coil On K1 or K2
Measure the resistance of each contactor coil. The nominal
resistance should be approximately 6-10 ohms for K1 and 1-4
ohms for K2.
NOTE
If the contactor circuit for K1 (step start contactor) is inoperative, no sound from the power supply compartment will be heard
when the LOW, MEDIUM, or HIGH button is depressed. If the
contactor circuit for K2 (run contactor) is inoperative, two clicks
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-1
will be heard when the transmitter LOW, MEDIUM, or HIGH
button is depressed. This is the step start contactor energizing
and de-energizing.
6.2.3 Symptom: Transmitter Will Not Turn ON-
One or More of the Front Panel Indicators is
Illuminated Red.
Possible Causes
Many of the transmitter fault circuits that appear on the front
panel will turn off the High voltage and not allow it to be turned
back on until the fault is cleared. The first step is to see if any of
the faults can be cleared by depressing the Reset button on the
front panel. Any indicator that cannot be cleared will remain
indicating RED. The fault still exists and therefore must be
repaired before the transmitter will become operational. See the
“Troubleshooting Front Panel Indicator Faults” paragraph of this
section.
6.2.4 Symptom: Transmitter Will Turn ON but Im-
mediately Turns OFF
One of More of the Front Panel Indicators is Illuminated Red.
The Transmitter May try to Turn ON twice and a Fault Indication
Illuminates Red.
Possible Causes
6.2.4.1 Transmitter Faults
Many of the transmitter fault circuits that appear on the front
panel will turn off the High voltage and allow it to be restarted
again because the fault does not exist until the high voltage is
applied. At that point the transmitter will fault again. First reset
the fault indicator by depressing the Reset button on the front
panel. If a fault still exists and the transmitter is restarted the
transmitter will turn on and then shut off with the appropriate
indicator showing RED. In the case of the Overcurrent, Overdrive and Underdrive overloads, the transmitter will try to restart
an additional time by itself before indicating the fault. The fault
still exists and therefore must be repaired before the transmitter
will become operational. See the “Troubleshooting Front Panel
Indicator Faults” paragraph of this section.
6.2.5 Symptom: Transmitter Turns ON but there is
NO Power Output.
Low, Medium or High Pushbuttons Illuminate but No Forward
Power or PA Current is Indicated but supply Voltage is Indicated
on the Multimeter.
Possible Causes
6.2.5.1 PA Turn-Off Command Given To Transmitter
The PA Turn-Off command in the transmitter will allow the high
voltage to be on but will not allow any of the RF Amps to be
turned on to produce power output. To check for a PA Turn-Off
command open the front center door and look for DS3 near the
bottom of the Modulation Encoder board A36. If transmitter high
voltage is on and DS3 is illuminated a PA Turn-Off command is
6-2
being given to the transmitter. Check the following items which
will generate a PA Turn-Off command.
6.2.5.2 PA Turn-Off Switch Set to the PA OFF Position
The PA Turn-Off switch is located on the Controller board.
Check to make sure this switch S5 is set to the PA-ON position.
6.2.5.3 External PA Turn-Off Circuit Activated
The External Interface board allows the use of the External PA
Turn-OFF command for customer applications such as
Day/Night switching on a Phasor. If this feature is connected,
make sure that the device associated with the PA Turn-Off is not
at fault. To check this simply remove the wire connected to the
Customer Remote control terminal strip at TB1 terminal 22. If
the PA Turn-Off is removed then the the transmitter is not at
fault.
6.2.5.4 Transmitter Type 4 and Type 5 Faults
Regulator faults that occur on the A to D board and the Analog
Input board will generate a Type 4 fault which will generate a
PA Turn-Off command. A Type 5 fault is generated by the A to
D board Conversion Error fault circuit and will also produce a
PA Turn-Off command. If any of these fault indicators are
illuminated on the front panel then refer to the “Troubleshooting
Front Panel Indicator Faults” paragraph of this section.
6.2.5.5 Power Output Of Transmitter Is Lowered To Zero
If the transmitter output is zero yet the PA Turn-Off LED on the
Modulation Encoder Board is not illuminated, This indicates that
the power output may be lowered to zero. First verify that the
PA ON LED A36DS4 is illuminated on the Modulation Encoder
Board. Connect the probe on the right hand side of the center
compartment to A35TP7 on the Analog Input board. Operate the
multimeter switch to the PROBE +VDC (0-3) position and
measure the voltage. If the voltage is zero that indicates that no
DC voltage relative to the power output is being produced. Hold
the RAISE button on the transmitter and note if the DC voltage
does start to raise. If it does the transmitter power output should
also be increasing at this time. Hold the RAISE button until the
desired output power is reached. Reset the other power levels to
the desired output power. A resetting of the power output latches
to the Zero position normally only occurs when the backup
memory power supply fails when the transmitter AC power is
off. Check the +5V “B” supply on the controller if this is a
common occurrence.
If the voltage on TP7 on the Analog input board is zero and
cannot be raised by the raise and lower control then the Power
control circuitry on the Analog input board and the Controller
board must be investigated. See the specific section for each of
these boards for individual troubleshooting information.
6.2.6 Symptom: Transmitter Turns ON but Trans-
mitter Output is Lower than Normal
Low, Medium or High Push-button Indicators Illuminate
Antenna and/or Bandpass VSWR Fault LED is Illuminated and
Power may Not be able to be Raised without the Lower Indicator
Reducing the Power Automatically.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Possible Causes
6.2.6.1 Antenna VSWR Caused By An Impedance Change
In The Transmitter Load
If the transmitter load changes sufficiently enough to cause a
VSWR overload the transmitter will automatically lower the
power until the VSWR is cleared. If the mismatch is severe
enough the power output could go below 500W. If the problem
still exists and the RAISE button is depressed the transmitter will
raise until the VSWR threshold is exceeded then it will lower.
Select the Antenna Null position on the Multimeter. It will
probably read upscale. If the Bandpass Filter Null also reads
upscale it indicates an antenna problem. See the “Emergency
Operating Procedures” section of the manual on operating the
transmitter in this condition until the antenna can be repaired.
If the power output of the transmitter did not lower significantly,
and now can be raised back to normal by depressing the RAISE
button, this indicates an intermittent VSWR condition caused by
any one of numerous items, typically arcing of a failed component or lighting strikes. The transmitter power can be increased
and if the problem occurs again the transmitter will protect itself.
For more information on the VSWR circuit operation and problem identification see “ Troubleshooting Front Panel Indicator
Faults.”
6.2.6.2 Bandpass Filter VSWR Caused By Problems In The
Output Network
If a problem occurs in the output network of the transmitter due
to a failing component then the Bandpass Filter VSWR circuit
will protect the transmitter. If the power output has lowered and
and cannot be raised any higher without the transmitter automatically lowering the power, check the Bandpass Filter Null indication on the front panel multimeter. If it indicates upscale and
Antenna Null indication indicates near zero then a problem has
occurred in the output network and should be attended to as soon
as possible. Until the transmitter can be repaired:
1. Do NOT attempt to further raise Power.
2. Do NOT change Tuning or Loading controls.
For further information on Troubleshooting the Bandpass filter
circuit and Output network, see the “Troubleshooting Front
Panel Indicator Faults.”
NOTE
During normal operation if a VSWR occurs on the antenna system both the Antenna and Bandpass filter indicators may flash
but normally the antenna VSWR is set to trip slightly before the
Bandpass filter. If just the Bandpass Filter indicator flashes this
indicates a problem in the output network.
6.2.7 Symptom: Transmitter Turns ON but Trans-
mitter will Not Modulate
Low, Medium or High Push-button Indicators Illuminate
Possible Causes
It should be noted that because the transmitter audio is added to
a DC voltage which is relative to the power output level, any
problem that would affect this DC + Audio would also affect the
power level. This DC is added to the audio very early in the
03/16/2009
analog input circuitry, therefore if the transmitter power output
control functions normally yet there is not modulation then the
problem is either occurring before it enters the transmitter or is
occurring in the first few stages of the analog input board.
6.2.7.1 Modulation Not Reaching Transmitter
Verify that the modulating audio is reaching the transmitter
audio input terminals on the External interface board.
6.2.7.2 Analog Input Board
Only the circuitry associated with the Analog input board active
components A35 U6, U9, and U7 would affect the modulation
but not the power control. Higher THD can occur in the transmitter due to failed RF Amps and this is discussed in paragraph
“Higher Than Normal Audio Distortion.”
6.3 Troubleshooting Front Panel Indica-
tor Faults
The following is a list of all the transmitter faults that appear on
the front mimic panel of the transmitter. They are grouped in
order of the Type of faults they are. The Type of fault refers to
the Type of transmitter action that occurs when when that
particular fault is detected. For a more detailed description of the
transmitter action of each fault type, see Section 7, System
Operation, in this Technical Manual.
6.4 Overloads- Intermittent or Continu-
ous (indicator RED or AMBER)
6.4.1 Main Power Supply Overcurrent Fault
The DX-10 Overcurrent fault monitors the actual supply current
of the high voltage supply and will generate a type 1 fault any
time the PA current reaches a preset overload level. Two Supply
current overloads are actually combined into the fault called
Overcurrent. Both the Average and Peak supply currents are
monitored.
Possible causes for Overcurrent Overloads
6.4.1.1 Random Faults With Audio
If the transmitter incurs random faults with audio, this indicates
that the peak overload current is being exceeded. This is most
commonly caused by over modulating the transmitter or by sub
audible signals. Check you modulation level. It may be wise to
check the calibration of the modulation monitor if it has not been
calibrated recently. It is possible the monitor is reading low and
in fact the transmitter is being overmodulated.
If the modulation level is proper, then there may be sub audible
signals getting to the transmitter. The DX-10 transmitter and
some modern day audio equipment can pass sub audible signals.
Take note of when the overloads occur. It may be possible to
relate the overloads to a particular source. Turntable rumble
especially START-UP RUMBLE can be of such level to cause
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-3
Table 6-1
Fault Types
I. TYPE 1 — TURN TRANSMITTER OFF.
a. a. External Interlock.
b. b. Door Interlock.
c. c. Air Supply Fault (Air Flow Switch).
d. d. High Voltage Supply Failure (High Voltage Supply Protection Circuit).
e. e. High Voltage Supply Overvoltage.
f. f. Modulation Encoder Cable Interlock Fault.
g. g. Output Monitor, +5 Volt Supply Fault.
h. h. Output Monitor, -5 Volt Supply Fault.
i. i. DC Regulator, +5 Volt Supply Fault.
j. j. DC Regulator, B- Supply Fault.
II. TYPE 2 — RECYCLES TRANSMITTER OFF/ON ONE TIME.
a. a. RF Underdrive.
b. b. RF Overdrive.
c. c. Supply Current Overload.
III. TYPE 3 — LOWERS TRANSMITTER OUTPUT POWER.
a. a. Successive VSWRs (either Bandpass Filter or Antenna VSWRs).
IV. TYPE 4 — APPLY PA TURNOFF.
a. b. A/D Converter Board, +15 volt supply fault.
b. c. A/D Converter Board, -15 volt supply fault.
c. d. A/D Converter Board, +5 volt supply fault.
d. e. Analog Input Board, +15 volt supply fault.
e. f. Analog Input Board, -15 volt supply fault.
V. TYPE 5 — CLEAR MODULATOR DIGITAL AUDIO DATA, APPLIES PA TURN-OFF.
a. a. Conversion Error.
VI. TYPE 6 — ONLY DISPLAYS FAULT.
a. a. Envelope Error.
VII. TYPE 7 — TRANSMITTER INHIBITED FROM TURN-ON.
a. a. Primary power contactor K1 does not close.
Overcurrent overloads. The solution may be to install a filter in
the program line. Some audio processors have switchable low
frequency cut-off filters. These will filter out the sub audible
signals without degrading the ON AIR sound of the transmitter.
Some audio processors have a DC offset which can shift with
modulation, at either a subaudible or audio rate. This shifting
offset voltage will generate carrier shift, and if the “offset” shifts
in a positive direction at the same time as positive modulation
peaks occur, a DC overload would occur. The most common
cause of this type of problem is an unacceptable amount of
shifting “DC” offset from the program source driving the transmitter. Another indication of shifting dc offset is excessive
movement of the power output meter with modulation. Even as
little as 10MV of DC shift can cause significant carrier shift.
If the setting of the Overcurrent overloads needs to be checked,
see the Maintenance section of the manual.
6-4
CAUTION
DO NOT MAKE ANY ADJUSTMENTS TO THE OVERCURRENT
OVERLOAD SETTINGS UNTIL ALL OF THE PRECEDING CHECKS
LISTED ABOVE HAVE BEEN PERFORMED. TRANSMITTER DAMAGE COULD OCCUR IF THE OVERCURRENT OVERLOADS ARE
IMPROPERLY SET.
6.4.1.2 Faults With Tone Modulation
If the transmitter is being tested with tone modulation it is
possible to generate Overcurrent overloads with high level low
frequency modulation. Second, many audio test generators will
also have a DC offset voltage in their output when they are
switched from one frequency range to another; this offset can
cause an overload. Third, if the transmitter is turned ON with a
high level, low frequency tone at the audio input, overloads may
occur due to the surge current produced as the transmitter is
ramping up to power with full modulation.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
6.4.1.3 Supply Current Overloads on Turn On
Normally if the transmitter indicates a Overcurrent overload on
turn on, the first most likely cause is the transmitter has low
frequency, high level modulation applied. Lower the modulation
level before turning on the transmitter. The other possible cause
would be a problem with the power control circuit such that when
the transmitter high voltage is coming up the PA Turn-Off
command is being released prematurely and therefore the transmitter is attempting to produce power at the same time as the
power supply capacitance is still charging up. This problem
would most likely be on the Controller board or Analog Input
board. An indication of this problem would also be the PA
Current meter moving upscale faster than normal before overloading.
If the transmitter will not stay on because of the overload, set the
PA Turn-Off switch to the PA-Off position. If PA current still
continues to move upscale when the high voltage is turned on,
then the problem is most likely due to a problem in the power
supply. Note that the power supply can be isolated from the RF
Amplifiers by removing F1 through F7 on the Fuse board A24.
F8 cannot be removed because this is the supply for the RF
Drivers and an Underdrive overload would occur on turn on.
NOTE
The transmitter may not indicate an OVERCURRENT overload if
a direct short exists on the high voltage supply such as in the
case of a defective HV shorting switch. The overload indicated
would be an UNDERDRIVE fault. This is because if the HV does
not come up due to a short then the Driver supply will also not
reach the proper voltage and an Underdrive condition will be
sensed FIRST.
6.5 Main Power Supply-Overvoltage
Fault
Possible Causes
6.5.0.1 Supply Voltage Too High
If the transmitter will remain on the air long enough to measure
the Supply voltage on the front panel multimeter, compare this
reading to that recorded on the factory test data sheet. If the
reading is significantly higher, the tapping on the high voltage
transformer must be changed. If the transmitter will not stay on
long enough for a measurement, then tap the transformer down
to obtain the next lowest supply voltage. If the AC input line
voltage is not known then it should be measured and both the
high and low voltage transformers set to the proper setting.
voltage power supply transformer to the next highest primary
number. If the transformer is presently tapped to 240/0, change
the tapping to 240/+11 to reduce the supply voltage.
If the transmitter has been operating with the proper supply
voltage for some time, and only recently increased, check to see
if the power line voltage has increased for the normal operating
voltage.
NOTE
The worst case condition for incurring Overvoltage overloads
will be when the high voltage is on and the power output is at
zero. The supply voltage will be at its highest. The transmitter
should not incur an overload in this condition.
6.5.1 Main Power Supply-Supply Fault
The main function of the Main Power Supply Fault is to not allow
the transmitter to operate if an imbalance exists in the 3-phase
high voltage supply such as to cause excessive heating of the
high voltage transformer. Imbalances of the high voltage supply
transformer can cause overheating of the windings and therefore
a shortened life of the transformer or other potential problems.
Note that if the overload occurs only intermittently, the power
supply balance is marginal and is probably faulting on low
frequency modulation peaks. If the fault occurs consistently even
without modulation, the problem is more serious and should be
attended to immediately.
Possible Causes
6.5.1.1 Input AC 3 Phase Line Imbalance
Measure the 3 phase line voltages. They should be within 5% of
each other to prevent excessive heating of the windings of the
high voltage transformer. If the line voltages are not in balance,
the power company should be contacted to rectify the problem.
Note that line imbalance not only affects the transformer heating,
but excessive line imbalance will also degrade the Transmitter
performance is terms of AM signal to noise.
WARNING
ENSURE ALL POWER IS REMOVED FROM THE TRANSMITTER
AND THAT THE GROUNDING STICK HAS BEEN USED TO DISCHARGE ANY RESIDUAL VOLTAGE WHERE POWER HAS
BEEN APPLIED BEFORE PERFORMING THE FOLLOWING
STEPS.
6.5.1.2 Open High Voltage Rectifier(s)
If one or more of the high voltage rectifiers were to open, this
would create an imbalance in the HV supply enough to cause
Supply faults. Ohmmeter the HV supply rectifiers for an open.
6.5.1.3 Failed High Voltage Transformer
WARNING
ENSURE ALL POWER IS REMOVED FROM TRANSMITTER AND
THAT GROUNDING STICK HAS BEEN USED TO DISCHARGE
ANY RESIDUAL VOLTAGE WHERE POWER HAS BEEN APPLIED BEFORE THE TAPS ON THE HIGH VOLTAGE AND/OR
LOW VOLTAGE TRANSFORMERS ARE CHANGED.
For example if the supply voltage reading is too high, remove all
AC power being supplied to the transmitter and retap the high
03/16/2009
If the rectifiers check good and the AC line voltage balance is
within specifications, then the High voltage transformer may
have failed windings in one of the sections. If the transmitter will
operate at some power level and modulation, allow it to run for
a short time. Shut the transmitter down and remove all AC
power. open the power supply compartment and feel each set of
windings of the High voltage transformer. If one set is hotter than
the other this indicates an imbalance in the transformer. Again
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-5
if the Line voltage is balanced and the HV rectifiers are good
then the transformer must be suspect.
6.5.1.4 Low Frequency, High Level Modulation
The sensing circuit for the Supply overload fault determines the
amount of full wave power supply ripple on the high voltage
supply. This 100Hz/120Hz component will be the greatest when
the transmitter is modulated at this audio frequency range. If the
audio modulation is overmodulated with frequencies from 90140Hz, this could be sensed as a fault and cause a false trip. This
condition should normally not occur if the three phase line
voltages are well balanced. If the balance is marginal, then
Supply fault overloads could occur.
If the setting of the Supply Fault overload needs to be checked,
see “Power Supply Protection Overload,” in the Maintenance
section of the manual.
6.5.2.2 Failed Driver Supply
If the main supply voltage does deflect upward, but the DRIVER
+VDC indication does not this indicates a problem in the driver
supply voltage circuit. Check F8 on the Fuse board A24. Also
check L3, C13 through C15 and R13 through R15.
6.5.2.3 No Drive To The Driver Stage
The Driver modules require a minimum of 20Vp-p of drive to
each module. This drive is generated on the Oscillator board,
and amplified by the Buffer and Predriver. If any of these stages
is inoperative an Underdrive fault will occur. With only the low
voltage ON the Oscillator, Buffer, and Predriver Indicator LEDs
should all be GREEN. If any of them are RED, troubleshoot that
particular stage using the procedures listed in this Troubleshooting section. To measure the drive to the Driver stage see the
Maintenance Section on Predriver checkout.
6.5.2.4 RF Driver Module Failure
CAUTION
DO NOT MAKE ANY ADJUSTMENTS TO THE OVERCURRENT
OVERLOAD SETTINGS UNTIL ALL OF THE PRECEDING CHECKS
LISTED ABOVE HAVE BEEN PERFORMED. TRANSMITTER DAMAGE COULD OCCUR IF THE OVERCURRENT OVERLOADS ARE
IMPROPERLY SET.
6.5.2 RF Driver-Underdrive Fault
Typically because the DX-10 uses a Gain controlled driver stage,
the chances of incurring intermittent underdrive faults is low
compared with a drive system that relies on the stability of a fixed
power supply. If Underdrive faults occur, they will most likely
be of a consistent nature, in other words the fault will be there at
all times. The only times nuisance faults would occur is when
the regulator circuit was producing marginal drive levels thus
causing the Underdrive fault to occur on positive modulation
peaks. In either case the following are possible causes for Underdrive faults.
6.5.2.1 High Voltage Supply Short
The RF Driver stage operates at 1/2 (115\VDC) of the main
supply high voltage (230VDC). Therefore if the high voltage
supply is not present, the Driver supply will also not be up. The
control circuitry allows 1.1 seconds for the driver supply to reach
full drive level after the step start contactor engages. This assumes that there is no other load on the high voltage supply. If
there is a higher load on the supply which would be the case with
a defective High voltage shorting switch, then the drive would
not be proper and the Underdrive overload would shut off the
transmitter before the main contactor pulled in and cause possible damage to the supply.
Operate the RF Multimeter select on the DX-10 to the DRIVER
+VDC (0-3) X100 position. Depress the LOW power on button
while watching the meter. Normally the meter should reach near
the 100VDC mark within 1 second of the step start contactor
energizing (first click). If it does not deflect upscale, then note
the supply voltage on the front panel multimeter. It normally
should deflect upwards toward the 220VDC mark within the first
second of turn on. If it does not then troubleshoot the high voltage
supply for a short or no supply voltage.
6-6
The DX-10 transmitter is designed with a Gain Controlled driver
stage with redundant Driver modules such that 1/2 of a driver
module can fail yet the same drive level will be maintained. If
more than 1/2 of a section of a Driver fails it may not be possible
for the driver stage to keep the drive level within limits. To check
for a Driver Module failure, open the center front door and
through the holes in the inner front door, view the LEDs on each
of the Driver modules. Depress the LOW Power button and note
if any of the LEDs illuminate before the transmitter shuts back
off. If any of the LEDs illuminate, remove all power from the
transmitter and replace that module. If a spare module is not
available, exchange the bad module with RF Amp Step #42.
6.5.2.5 Excessive RF Amplifier Failure
Even though very highly unlikely in the DX-10 transmitter, a
failure of a number of RF Amplifiers could load the drive level
down sufficiently enough to use all the reserve output available
in the Driver stage. To check for this type of failure, open the
center front door, and observe the RF Amplifier LEDs through
the holes in the inner front door. Depress the LOW power on
button and note any LEDs that illuminate when the high voltage
is applied. If more than 5 LEDs are lit on any combination of
modules, these modules should be repaired before proceeding
with further attempts to troubleshoot the Underdrive problem.
6.5.2.6 Driver Supply Regulator Failure
Once it has been verified that the Driver power supply is present,
(DRIVER +VDC deflecting towards 110VDC), the Driver Supply regulator can now be checked. Operate the RF Multimeter
switch to the DRIVER SECT 1A position. Depress the LOW
power on button. The meter indication should deflect upward
before the transmitter shuts back down. How high it deflects
depends on the original operating voltage recorded in the test
data sheet. If the reading does not deflect upward the Driver
Supply regulator is at fault and should be serviced. For more
information on Driver Supply Regulator troubleshooting see
Section E in the manual.
6.5.2.7 Driver Supply Regulator Loop Select
If it is determined that the Driver Supply Regulator is the
problem, it may be possible to get the transmitter operational by
switching the regulator loop select to the OPEN LOOP position.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
This switch is set through an access hole in the right side wall of
the center compartment. With only the low voltage on, locate the
Loop select switch A22S1 through the access hole above the
Oscillator board. Set it to the OPEN position. If the
transmitter will now operate, the problem is in the Closed Loop
regulator section of the Driver Supply Regulator. The transmitter
will operate normally with the loop set in the OPEN position, but
it will not have the Automatic gain control feature enabled.
6.5.2.8 Severe Driver Mistuning
The DX-10 Driver Gain controlled circuit normally will compensate for slight mistuning errors by increasing the output of
the driver stage itself. If the mistuning is more severe then the
regulator will not be able to keep the Drive level in range. To
check the RF driver tuning see “RF DRIVER ADJUSTMENTS”
in the Maintenance section. Note that this procedure describes
how to tune the Driver from scratch. The Driver stage should
have already been operating in this case. It is possible for one of
the Driver tuning capacitors A14C12-C14 to have failed and
therefore change the tuning. Failed capacitors can sometimes be
identified by checking for abnormal heating on a capacitor once
it been operated for a short time. If the setting of the Driver tuning
coil L2 has been tampered with, it can normally be preset back
to the setting listed in the factory test data sheet.
6.5.2.9 Drive Sensing Circuit Failure
This problem assumes the drive level to be proper but a false
Overload is being generated. See “RF UNDERDRIVE OVERLOAD ADJUSTMENT” procedure in the Maintenance section
for more information on measuring drive levels and checking the
overload setting.
6.6 RF Driver-Overdrive Fault
Possible Causes
6.6.0.1 Driver Supply Regulator Failure
The DX-10 uses the Gain Controlling regulator for the driver
supply so the only time an Overdrive fault would occur is if a
fault occurred in the regulator itself. If the transmitter incurs an
Overdrive fault as soon as the high voltage is applied it is still
possible to see if the regulator has a problem before the transmitter turns off. Operate the RF Multimeter to the DRIVER
SECT. 1A position. Monitor the meter reading while depressing
the LOW power on button. As soon as the transmitter begins to
turn on note the meter deflection. It will probably deflect near
the 115V mark. Now operate the RF Multimeter switch to the
DRIVER SECT.1B position. Again depress the LOW power
button and note the meter deflection. If the meter deflects upward
toward the 110VDC mark, this indicates that the Driver Supply
regulator is turned fully on due to some malfunction. See the
Troubleshooting section of the Driver Supply Regulator, Section
E.
6.6.0.2 Driver Supply Regulator Loop Select
If it is determined that the Driver Supply Regulator is the
problem, it may be possible to get the transmitter operational by
03/16/2009
switching the regulator loop select to the OPEN LOOP position.
This switch is set through an access hole in the right side wall of
the center compartment. With only the low voltage on, locate the
Loop select switch A22S1 through the access hole above the
Oscillator board. Set it to the OPEN position. If the transmitter
will now operate, the problem is in the Closed Loop regulator
section of the Driver Supply Regulator. The transmitter will
operate normally with the loop set in the OPEN position, but it
will not have the Automatic gain control feature enabled.
If it is desired to measure the drive level or if it is suspected that
the drive level setting or overload has been tampered with, see
“Overdrive Overload Adjustment” in the Maintenance section
of the manual.
6.6.0.3 Drive Sensing Circuit Failure
This problem assumes the drive level to be proper but a false
Overload is being generated. See “RF UNDERDRIVE OVERLOAD ADJUSTMENT” procedure in the Maintenance section
for more information on measuring drive levels and checking the
overload setting.
6.7 Interlocks
6.7.1 Door Interlock
There are only two door interlock circuits in the transmitter. One
is for the front door of the power supply compartment and the
second is for the inner front door of the center RF compartment.
If a Door Interlock fault is indicated check to make sure both
doors are securely closed especially where the plunger contacts
the interlock switch itself.
WARNING
ENSURE ALL POWER IS REMOVED FROM TRANSMITTER AND
THAT GROUNDING STICK HAS BEEN USED TO DISCHARGE
ANY RESIDUAL POTENTIAL WHERE POWER HAS BEEN APPLIED BEFORE PERFORMING THE FOLLOWING STEPS.
If the doors appear to be closing properly then remove all power
and ohmmeter each half of each switch for continuity when the
switch plunger is depressed.
6.7.2 External Interlock
If the External Interlock indicator is illuminated RED check the
following:
6.7.2.1 External Interlock Terminals Open
If the external interlock feature was not utilized in the transmitter
a jumper should be located between the remote control terminals
TB1-1 and TB1-2. Ensure that the jumper wire is properly
connected. If a device requiring an external interlock is connected to these terminals, (Phasor door interlock, dummy load,
etc.) make sure that this device is providing closed contacts in
the normal operating condition.
6.7.2.2 External Interlock Fuse F6
The external interlock terminals TB1-1 and TB1-2 are protected
by a fuse in case these terminals are accidentally shorted to
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-7
ground. Check F6 for an open and replace if failed. Make sure
that there are no shorts on the External interlock line. F6 is
located by the contactor K2 under the metal cover in the Power
Supply compartment, see Figure 3-4.
6.7.2.3 External Interlock Relay K4
If the F6 is good and the external interlock connections are
closed, then verify that K4 is energized when the low voltage is
on and the external interlock is closed. If it is not suspect an open
coil of K4.
6.7.3 Air Interlock
Air interlock problems will be either of an intermittent nature
such as would occur as an air filter becomes blocked, or consistent a during a blower failure. Possible causes of an Air Interlock
fault are as follows:
6.7.3.1 Blower Not Operating Properly, Failed/Running
Backward
The transmitter will turn on momentarily with high voltage and
power output even with NO air flow. There is a delay of approximately 0.3 seconds before an air interlock will turn off the
transmitter after detecting a loss of air, once the Run contactor
K2 energizes. Open the center front door and depress the LOW
power on pushbutton. Feel the airflow coming through the holes
from the inner front door. A steady stream of air should be felt
coming out of the holes. If it is not, first verify that the blower is
running. To verify that it is operating in the proper direction, turn
the transmitter on and as soon as it shuts off on the Air interlock,
remove all AC power, and quickly remove the rear center panel.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Locate the blower fan in the lower right corner of the RF
compartment. Note in which direction the blades of the blower
are rotating. The blades should be rotating CCW, such as to blow
air into the RF compartment. Note that the blower will rotate at
a slow rate for approximately 30 seconds after power is removed.
WARNING
KEEP AWAY FROM ROTATING BLADES EVEN WITH THE
POWER REMOVED.
NOTE
Temporarily remove the air filters from the rear panel of the Output Network compartment. If the transmitter now operates with
the filters removed, clean or replace the filters.
NOTE
The Air interlock switch has built in hysteresis which requires
that more air pressure be required to set the switch to the ON
position (sufficient airflow), than what is required to keep it on.
Therefore it is possible to turn on the transmitter without the filters and then replace the filters while it is running and still not
generate an AIR interlock.
6-8
6.7.3.2 Top Air Exhaust Restricted
If ductwork is installed to the top of the transmitter for exhausting
the air, and a restriction is present in the exhaust, it is possible to
generate an Air Interlock. If an exhaust restriction is suspected,
operate the transmitter with the front center door open. Because
the exhaust is no longer going through the top, the transmitter
should not incur an Air interlock.
6.7.3.3 Center Rear Panel Open
The Transmitter will not operate with the rear center panel open
or partially open due to the loss of air pressure in the RF
compartment.
6.7.3.4 Air Interlock Sensing Circuitry
The Air interlock sensing circuitry consists of U12-U17 on the
LED board. Measure the DC voltage at J5-1 on the LED board.
Depress the LOW power on button. If the voltage at this point
goes to approximately +8VDC before the transmitter turns off,
then the air interlock switch is operating and the LED board
circuitry is suspect.
6.7.3.5 Air Interlock Switch S7
If +8VDC does not appear at J5-1 on the LED board, and all the
above checks have been made, then the Air interlock switch itself
is suspect.
6.7.3.5.1
Air Switch Adjustment
If all the above tests have been performed,then it may be possible
that the switch may need readjustment. This would be definitely
the case if the transmitter is operated at a higher altitudes or if
the transmitter was originally tested at 60Hz AC input operation
and is now operating at 50Hz AC input frequency. If the setting
of the air switch needs to be checked, see “AIRFLOW SWITCH
ADJUSTMENTS” in the Maintenance section of the manual.
6.8 All Other Front Panel Faults
6.8.1 Oscillator Fault
If the transmitter is incurring RF Drive Underdrive faults, and
the Oscillator front panel LED is illuminated RED, the Oscillator
output is not sufficient. To troubleshoot the Oscillator see the
troubleshooting portion of the Oscillator section of the Manual,
Section A. Also see the Emergency Operating Procedures, paragraph “Crystal Failure”
6.8.2 Buffer Fault
If the transmitter is incurring RF Drive Underdrive faults, and
the Buffer front panel LED is illuminated RED, the Buffer output
is not sufficient. To troubleshoot the Buffer, see the troubleshooting portion of the Buffer section of the Manual, Section
B.
6.8.3 Predriver Fault
If the transmitter is incurring RF Drive Underdrive faults, and
the Predriver front panel LED is illuminated RED, the Predriver
output is not sufficient. To troubleshoot the Predriver see the
troubleshooting portions of the RF Amplifier Section C, and the
Driver Combiner/Motherboard Section D.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM TRANSMITTER AND GROUNDING STICK IS USED TO GROUND ALL
POINTS WHERE AC OR RF POWER HAS BEEN APPLIED BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
Only one half of the Predriver module is used at one time. If a
Predriver module failure is indicated by a RED LED illuminated
on the Predriver module, then the other half of the module can
be quickly switched in. To do this remove all AC power from
the transmitter and open the inner front door exposing the RF
Amplifier modules. Locate and remove the Predriver module.
From where the module was removed, locate and set the Predriver select switch A14S1 on the Driver Combiner/Motherboard to the other position to select the other half of the Predriver.
Reinstall the predriver module and close the inner front door.
6.8.4 RF Amp Envelope Error Fault
The function of the Envelope Error fault indicator is to indicate
when the demodulated RF envelope does not match the audio
modulating the transmitter. This will then alert the operator that
an RF Amplifier may have failed. This circuit does no other
function except illuminate the LED and remote output if connected. It will not perform a PA Turn-Off or shut off the high
voltage. It is also important to remember that since this circuit is
sensitive to small changes in power and distortion as when an
RF Amplifier fails,it is also sensitive to transmitter load variations. If the transmitter is not tuned properly for minimum
indications on the Antenna Null position on the multimeter, the
Envelope Error circuit may indicate an Error when none exists.
• Use the following guidelines when evaluating an Envelope
Error Fault.
If No RF Amp module fault LEDs are illuminated, and the
transmitter appears to be tuned properly, then the transmitter
distortion must be looked at to determine if an RF Amp is still
at fault but the LED is not illuminated. See paragraph on “Higher
Than Normal Audio Distortion.” If no RF Amps are at fault and
the Envelope Error LED is RED, then the detector circuit may
need readjustment or is defective. See paragraph entitled “Envelope Error Fault Indicator Adjust,” for adjustment instructions
and the LED board Section Q, for theory and troubleshooting of
the detector circuitry.
6.8.5 Analog Input +15V and -15V Supply Faults
If either of the Analog Input +15V or -15V Fault LED’s are RED,
this indicates that the Supply has failed. The transmitter will
generate a PA Turn-Off command so no power output will be
produced. With the low voltage on, measure the voltage at F2 on
the Analog Input board and verify that it is approximately
+22VDC. Measure the voltage at F3 and verify that it is -22VDC.
Turn off the transmitter and remove all AC power. Check both
F2 (+15V) and F3 (-15V). If one is failed replace the fuse and
try again. If the fuse fails again, troubleshoot the regulator
circuit. See “Troubleshooting the Analog Input board” in Section
J of the Manual.
NOTE
It is sometimes possible for the regulator circuit to lock into a
fault condition if the output of the regulator is accidentally
shorted. If this occurs simply remove all AC power from the
transmitter for approximately 1 minute to allow the power supply
to bleed off. Reapply AC power and note if the regulator is now
reset.
6.8.6 A to D Converter +15V, -15V, and +5V Supply
Faults
If any of the A to D Converter LED’s (+15V, -15V, or +5V) are
RED, this indicates that the Supply has failed. The transmitter
will generate a PA Turn-Off command so no power output will
be produced. With the low voltage on, measure the voltage at F1
ENVELOPE ERROR LED
POWER OUTPUT
POSSIBLE PROBLEM
Steady State RED
Unchanged
False Error, Check antenna for changed
common point impedance, and check transmitter tuning
Steady State RED
Lower than Normal at all powers
RF Amp Failure Check LEDs on RF Amp
Modules from Step 1-18*
Flashing RED with Modulation
OK @ 1kW, LOW
@ 1-kW
RF Amp Failure, Check LEDs on RF
AMP Modules from Step 6-18* Flashing
RED with Modulation
OK @ all Power
Levels
RF Amp Failure, Check LEDs on RF Amp
Modules from Step 18-42*
Flashing RED with Modulation
OK @ all Power
Levels
If NO RF Amp LEDs are lit, suspect load
change, check tuning. Also, decreased antenna bandwidth will cause the LED to
flash with high level, high frequency
modulation.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-9
on the A to D Converter board and verify that it is approximately
+22 VDC. Measure the voltage at F2 and verity that it is
approximately +22 VDC, and measure the voltage at F4 and
verify that it is approximately +8 VDC. Turn off the transmitter
and remove all AC power. Check F1 (-15V supply fuse), F2
(+15V) and F4 (+5V). If one has failed replace the fuse and try
again. If the fuse fails again, troubleshoot the regulator circuit.
See “Troubleshooting the A to D Converter Board,” in Section
K of the Manual.
NOTE
It is sometimes possible for the regulator circuit to lock into a
fault condition if the output of the regulator is accidentally
shorted. If this occurs simply remove all AC power from the
transmitter for approximately 1 minute to allow the power supply
to bleed off. Reapply AC power and note if the regulator is now
reset.
6.8.7 A to D Converter Conversion Error Fault
The A to D Converter requires a sample of the RF drive to
develop the sample frequency for the A to D converter IC. If this
sample is missing or there is a fault in the A to D conversion
process, the transmitter will output a Conversion Error Fault
which will produce a PA Turn-OFF command, thus allowing the
high voltage to remain on. No RF output will be produced. For
additional information on troubleshooting the A to D converter
for a Conversion Error, see “Conversion Error Troubleshooting”
in Section K of the Manual.
6.8.8 Modulation Encoder Cable Interlock
The Cable interlock is designed to prevent the transmitter high
voltage from coming up when an RF Amplifier is is removed
from the circuit. Possible damage could occur to the Combiner/Motherboards if the transmitter puts out power with an
Amp removed. The cable Interlock feature is accomplished
through the individual Modulation Encoder cables #503-#516.
If the transmitter will not turn on and the Cable Interlock LED
is RED, check the following.
6.8.8.1 All RF Amplifier Modules Are In Place
Remove all Power and open the inner front door exposing the
RF Amplifiers. Make sure all RF Amplifier modules are seated
properly. Some resistance is normal when inserting and removing Amps.
6.8.8.2 All Modulation Encoder Ribbon cables Are In Place
Locate the Modulation Encoder ribbon cables on the right side
of the Modulation Encoder board. Make sure all are seated
properly with the black “ears” fitting over the connector. Remove all AC power and open the inner front door exposing the
RF Amplifiers. The Modulation Encoder ribbon cables connect
on to the Combiner/Motherboards with the same type connectors
on the side of the motherboards facing the RF Amps. The
appropriate RF Amp must be removed to allow access to the
ribbon connectors. Check each of these connectors for proper
seating.
6.8.8.3 Isolating a Cable Interlock Problem
If none of the above tests remove the fault, it is possible to isolate
the problem further. With the low voltage on, measure the DC
voltage at the Modulation Encoder A36U63 pins 1-6,11,12, and
6-10
A36U64 pins 1-6,11,12. All these points should measure approximately +5VDC. Any one that is zero indicates an open
cable interlock. Use the Schematic for the Modulation Encoder
board to trace the line back to the appropriate connector. If all
the pins are +5VDC and the cable interlock LED is RED, then
troubleshoot the Cable interlock circuitry on the Modulation
Encoder board. For more information on the Cable interlock
circuitry, see Section L on the Modulation Encoder board.
6.8.9 DC Regulator +5V and B- Supply Faults
If either of the DC Regulator +5V or B- Fault LED’s are RED,
this indicates that the Supply has failed. The transmitter will turn
off and will not be able to be turned on until the fault is cleared.
With the low voltage on, measure the voltage at F1 on the DC
Regulator board and verify that it is approximately +8VDC.
Measure the voltage at F3 and verify that it is approximately
-8VDC. Turn off the transmitter and remove all AC power.
Check both F1 (+8V) and F3 (-8V). If one is failed replace the
fuse and try again. If the fuse fails again, troubleshoot the
regulator circuit. See “Troubleshooting the DC Regulator
board,” Section M of the Manual.
NOTE
It is sometimes possible for the regulator circuit to lock into a
fault condition if the output of the regulator is accidentally
shorted. If this occurs simply remove all AC power from the
transmitter for approximately 1 minute to allow the power supply
to bleed off. Reapply AC power and note if the regulator is now
reset.
6.8.10 Output Monitor +5V and -5V Supply Faults
If either of the Output Monitor +5V or -5V Fault LED’s are RED,
this indicates that the Supply has failed. The transmitter will turn
off and will not be able to be turned on until the fault is cleared.
With the low voltage on, measure the voltage at F1 on the DC
Regulator board and verify that it is approximately +8VDC.
Measure the voltage at F2 and verify that it is approximately
-8VDC. Turn off the transmitter and remove all AC power.
Check both F1 (+8V) and F2 (-8V). If one is failed replace the
fuse and try again. If the fuse fails again, troubleshoot the
regulator circuit. See “Troubleshooting the Output Monitor
board,” Section H of the Manual.
NOTE
It is sometimes possible for the regulator circuit to lock into a
fault condition if the output of the regulator is accidentally
shorted. If this occurs simply remove all AC power from the
transmitter for approximately 1 minute to allow the power supply
to bleed off. Reapply AC power and note if the regulator is now
reset.
6.8.11 Output Monitor VSWR Faults
A discussion of VSWR protection is included here to aid the
station technical and engineering staff in determining when
VSWR overloads may indicate a problem that should be located
and corrected. The VSWR protection built into the DX-10 transmitter is both for the protection of transmitter high power circuitry and the protection of external equipment which might be
installed between the transmitter and the antenna system. Operating at high power with a VSWR condition can result in high
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
voltages or currents in transmitter circuitry, or in circuits and
equipment between the transmitter and the antenna, or in antenna
impedance matching and coupling circuits. High voltages or
currents can result in arcing, overheating of components, or
component failure. In general, the VSWR overloads and limits
set in the transmitter’s protection circuitry should not be bypassed or increased beyond the recommended limits set at the
factory.
CAUTION
VSWR overload limit settings that exceed recommended values may result
in component damage or failure.
The DX-10 uses two nearly identical circuits to generate a
VSWR fault. The only difference between them is that they will
monitor the VSWR from two different locations. The Antenna
VSWR will monitor the the output load of the transmitter though
the Matching network of the transmitter. This VSWR sensor is
used to check the tuning of the transmitter since any change in
the antenna load will reflect back to this sensor. The matching
network (Loading and Tuning controls) can then be adjusted for
minimum VSWR. The Bandpass Filter VSWR circuit is located
such that it will be able to detect a VSWR that occurs anywhere
in the Transmitter Output network. Should any Output network
part fail, the transmitter will be protected. The Bandpass Filter
VSWR circuit will of course sense any antenna load changes
also, but its sensitivity is set lower such that an antenna VSWR
will be detected First by the Antenna VSWR circuit.
The first step in VSWR protection once a fault is detected is to
try to clear the fault. Most VSWR faults can be cleared by simply
causing the transmitter power output to go to zero for a brief
period of time. In the DX-10, this zero power output is accomplished by turning all PA sections off through modulator action.
This occurs so quickly (less than 20 milliseconds) that it may not
even be noticed by listeners, or will be simply a slight “click” or
“pop.” If a VSWR fault cannot be cleared by turning the transmitter off for a short period a number of times, the transmitter
will reduce power. This power reduction might be compared to
the “VSWR Foldback” used in some FM transmitters, where
power is reduced until a power level where safe operation can
continue is reached.
6.8.12 Two Stage VSWR Action
The VSWR circuits for both the Antenna and Bandpass Filter
VSWR protect the transmitter in a two stage process to prevent
undesirable program interruptions during nuisance trips such as
during static discharges, yet it will allow on air operation and
protection of the transmitter during more serious VSWR conditions. Both the Antenna and Bandpass Filter VSWR circuit
actions are identical.
6.8.13 First Stage VSWR Protection:
6.8.13.1.1
Action:
This is the first step in the VSWR protection. The VSWR
detectors act very quickly, in much less than a millisecond, to
detect a VSWR fault and turn off the transmitter RF output for
approximately 20 milliseconds or less. The VSWR status indicator flashes red for approximately one-half second, then returns
to green. If the VSWR condition is no longer present, nothing
else will occur. The VSWR LED will not stay RED since this is
not a serious type of VSWR condition which needs the attention
of an operator. These type of VSWR actions can occur indefinitely, as long as they do not occur for a consistent period of
longer than one second.
6.8.14 Second Stage VSWR Protection:
6.8.14.1 Symptom: The VSWR goes to Red and Remains on.
The Front Panel Lower Button Illuminates and the Transmitter
Front Panel PA current and Power Meters read quite low. Within
10 to 30 Seconds the Lower Indicator Extinguishes and the
Power output and PA Current have obtained a Lower than
Normal Power Level.
6.8.14.1.1
Action:
The transmitters VSWR sensor has detected a serious VSWR.
The first stage of VSWR protection was attempted, but the fault
existed for more than 1 second of continuous recycling. A
LOWER command was give to the transmitter to fold back the
power to a level to which the Transmitter could still operate. The
power level will remain here until given a RAISE command. If
the fault still exists the transmitter will again LOWER the power
and disregard the RAISE command. The source of the VSWR
fault must be repaired before full power operation can continue.
6.8.15 Combination of both Stages of the VSWR Cir-
cuit Action
6.8.15.1 Symptom: The VSWR LED flashes then remains lit
RED.
The Power Output Meter may make quick downward movements. The Lower Indicator flashes and the Power output goes
slightly lower each time. The ON-AIR sound may be interrupted
by numerous dropouts.
6.8.15.1.1
Action:
This problem would be the typical transmitter action during a
condition where sustained arcing was occurring in the output of
the transmitter during modulation peaks. During modulation
peaks an arc occurs and remains for longer than 1 second of
continual 1st stage VSWR actions. At this time a lower command is given during these modulation peaks. The transmitter
Power will progressively lower until the arcing on modulation
peaks will not be of long enough duration to generate a lower
command. The transmitter will operate safely in this condition
but it is recommended to lower the power further to prevent any
more arcing until the cause of the arcing can be determined.
6.8.13.1 Symptom: VSWR LED Flashes Red.
Front Panel Power Output Meter Drops Slightly and Returns to
Normal Power. A Slight “POP OR CLICK” is Heard on the Air.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-11
6.8.16 Antenna VSWR Fault
6.8.16.1 Antenna VSWR Caused By An Impedance Change
In The Transmitter Load
If the transmitter load changes sufficiently enough to cause a
VSWR overload the transmitter will automatically lower the
power until the VSWR is cleared. If the mismatch is severe
enough the power output could go below 500W. If the problem
still exists and the RAISE button is depressed the transmitter will
raise until the VSWR threshold is exceeded then it will lower.
Select the Antenna Null position on the Multimeter. It will
probably read upscale. If the Bandpass Filter Null also reads
upscale it indicates an antenna problem. See the “Emergency
Operating Procedures” section of the manual on operating the
transmitter in this condition until the antenna can be repaired.
6.8.17 Bandpass Filter VSWR Fault
6.8.17.1 Bandpass Filter VSWR Caused By Problems
In The Output Network If a problem occurs in the output network
of the transmitter due to a failing component then the Bandpass
Filter VSWR circuit will protect the transmitter. If the power
output has lowered and and cannot be raised any higher without
the transmitter automatically lowering the power, check the
Bandpass Filter Null indication on the front panel multimeter. If
it indicates upscale and Antenna Null indication indicates near
zero then a problem has occurred in the output network and
should be attended to as soon as possible. Until the transmitter
can be repaired:
1. Do NOT attempt to further raise Power.
2. Do NOT change Tuning or Loading controls
NOTE
During normal operation if a short term VSWR occurs such as
that caused by lighting or static discharge on the antenna system
both the Antenna and Bandpass filter indicators may flash but
normally the antenna VSWR is set to trip slightly before the
Bandpass filter. If just the Bandpass Filter indicator flashes this
indicates a problem in the output network.
For further information on the possible causes of VSWR Overloads see paragraph entitled “POSSIBLE CAUSES OF VSWR
OVERLOADS” in the Emergency Operating Procedures Section of the Manual.
This output power drop would be around 10%. A failure of a
higher step is not noticed as a drop in power at 1 kW for instance.
The audio distortion will also be slightly higher but may not be
noticeable with only one RF Amp failed. To see if an RF Amp
has failed, operate the transmitter at normal power. Open the
center front door and note if any Fault LED’s are illuminated on
any of the RF Amplifier cards. The transmitter will operate fine
in this condition with slightly less power and slightly more
distortion.
The failed module can be changed at any time or if the transmitter
cannot be taken off line the module can be patched into a non
critical position. If the module for instance is Step 6, it has an
active role in power output and modulation. By using the FlexPatch™ feature on the Modulation Encoder board, another good
module in a less active position can be assigned to step 6 while
the transmitter is still on the air. See paragraph entitled “Using
FlexPatch™ for Bypassing a Failed RF Amp.”
In some cases an RF Amp may be failed or a problem may exist
in the Modulation Encoder section for that Amp which does not
cause the LED on the module to illuminate. To find which step
has incurred a failure see paragraph entitled “Finding a Missing
Step” in this section.
6.9.2 Symptom: RF Output and PA Current Lower
than Normal-Antenna and/or Bandpass Filter
VSWR Indicators are RED
Probable Cause
6.9.2.1 Intermittent VSWR Condition Causing Power Foldback
A VSWR fault occurred such that the transmitter automatically
lowered the power output. Typical short term VSWRs such as
static discharges should not produce a lower command. The
power output can be raised back to normal but should the
transmitter intermittently keep lowering the power, then the
cause of the VSWR should be investigated. Paragraph entitled
“OUTPUT MONITOR VSWR FAULTS” in this section will
discuss VSWR faults in more detail. Paragraph entitled “Possible Causes of VSWR Overloads” in Section IV lists many
sources of VSWR problems.
6.9.3 Symptom: Loss of Positive Peak Capability
6.9 Initial Troubleshooting-less Serious,
Not OFF AIR Situations
6.9.1 Symptom: RF Output and PA Current Lower
than Normal-THD may be Higher and RF
Amp Envelope Error LED is Red or Flashing
Red.
Probable Causes
6.9.1.1 Failed RF Amplifier Module
Possible Causes
6.9.3.1 Power Supply Voltage Low
If the supply voltage for the RF Amplifiers is lower than normal,
the positive peak capability will be reduced. Nominal Supply
voltage should be between 220 and 230VDC at 10 kW output
power. Measure the supply voltage on the front panel multimeter. If it is not close to what was indicated on the factory test data
sheet then the high voltage transformer must be retapped. See
the INSTALLATION instructions for more information on selecting the proper transformer taps.
When an RF Amplifier module in positions Step 1-18, the
transmitter output power will drop when a 10 kW output power.
6-12
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
6.9.3.2 Audio Processor Equipment Defective or Incorrectly
Set
a big step failure at around Big Step 40. The modulation Encoder
waveform is also shown for that step.
Many problems with positive peaks are due to defective or
incorrectly setup processing equipment. Check the manual for
that particular piece of equipment for setup and service information.
The failed module should be replaced to obtain full positive peak
capability, but the transmitter will operate fine in this condition
and will only have some distortion on the positive peaks.
6.9.3.3 Incorrect Transmitter Tuning
6.9.4 Symptom: Higher than Normal Audio Distor-
If the transmitter loading and tuning have not been set properly
or a change in the antenna load has occurred then this can affect
the positive peaks. With the transmitter operating at full power
note the reading on the Antenna Null position of the front panel
multimeter. The indication should be near zero. The Loading and
tuning should be adjusted for a minimum indication here.
6.9.3.4 Transmitter Operated In FlexPatch™ Mode
If an RF Amp had failed and another RF Amp was substituted
using the FlexPatch™ feature, then the transmitter will have a
slightly reduced positive peak capability. The defective RF Amp
must be replaced and the the transmitter returned to its normal
mode before full positive peak capability will return.
6.9.3.5 Failed RF Amplifier
If an RF Amplifier fails then the transmitter positive peak
capability will decrease. The power output will also decrease if
one of the lower steps fail. Also distortion will increase slightly.
Check the RF Amp fault LED’s to see if any are illuminated.
6.9.3.6 Loss Of A Big Step
It is possible to have an RF Amplifier not putting out power yet
the Fault LED for that module not be illuminated. It should be
possible to see this problem on the detected audio waveform. If
a Big Step RF Amp is not operating properly an error in the
demodulated audio waveform will be present as seen in Figure
6-1. This kind of error can only be seen with steady state
modulation such as with a sine wave or more preferably a linear
ramp. If an RF Amp failure is suspected, operate the transmitter
at 11 kW at full modulation. Display the demodulated audio
output of a modulation monitor on a dual trace scope. If a big
step amplifier is not working, an error will be noticeable on the
display. To determine which amplifier is at fault, connect the
second channel of the scope to a probe and look at the output of
the modulation Encoder for each big step until the transition from
0 to 5VDC occurs at the same point in time as the error on the
wave form. See Figure 6-1. Since there are 42 big steps it helps
to know where to start to look on the modulation encoder. A good
rule is that the higher the positive peak level where the error
occurs, the higher the step number. An error in the middle of the
100% modulated sine wave at 11 kW is probably occurring
around step 20.
It must be remembered that a 100% modulated signal at 11 kW
is NOT using all the the big steps. In fact Steps 36 through 42
are only ON during positive peaks. To check these steps, a
nonsymetrical audio waveform should be used in order to modulate the transmitter with a steady state tone at 125% positive peak
without causing overmodulation on the negative peak and therefore carrier shift. Figure 6-2 shows a non symmetrical ramp
modulating to 125% positive peak and only 50% negative peak.
An error is also shown near the top of the positive peak indicating
03/16/2009
tion.
Possible Causes
6.9.4.1 Failed RF Amplifier(s)
If audible distortion is heard on the air and the program content
and audio processing equipment has already been verified to not
be the problem, then the next step is to determine if an RF
Amplifier has failed. When an RF Amplifier module in positions
Steps 1-18 fails, the transmitter output power will drop when at
1 kW output power. This output power drop would be around
10% for one module. a failure of a higher step is not noticed as
a drop in power at 1 kW for instance. The audio distortion will
also be slightly higher but may not be noticeable with only one
RF Amp failed. To see if an RF Amp has failed, operate the
transmitter at normal power. Open the center front door and note
if any Fault LEDs are illuminated on any of the RF Amplifier
cards. The transmitter will operate fine with an amplifier failed,
only with slightly less power and slightly more distortion.
The failed module can be changed at any time or if the transmitter
cannot be taken off line the module can be patched into a non
critical position. If the module for instance is Step 6, it has an
active role in power output and modulation. By using the Flex
Patch feature on the Modulation Encoder board, another good
module in a less active position can be assigned to step 6 while
the transmitter is still on the air. See paragraph entitled “Using
FlexPatch™ for Bypassing a Failed RF Amp.”
6.9.4.2 Finding a Missing Step
It is possible to have an RF Amplifier not putting out power yet
the Fault LED for that module is not illuminated. It should be
possible to see this problem on the detected audio waveform. If
a Big Step RF Amp is not operating properly an error in the
demodulated audio waveform will be present as seen in Figure
6-1. This kind of error can only be seen with steady state
modulation such as with a sine wave or more preferably a linear
ramp. If an RF Amp failure is suspected, operate the transmitter
at 11 kW at full modulation. Display the demodulated audio
output of a modulation monitor on a dual trace scope. If a big
step amplifier is not working, an error will be noticeable on the
display. To determine which amplifier is at fault, connect the
second channel of the scope to a probe and look at the output of
the modulation Encoder for each big step until the transition from
0 to 5VDC occurs at the same point in time as the error on the
wave form. See Figure 6-1. Since there are 42 big steps it helps
to know where to start to look on the modulation encoder. A good
rule is that the higher the positive peak level where the error
occurs, the higher the step number. An error in the middle of the
100% modulated sine wave at 11 kW is probably occurring
around step 20.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-13
Figure 6-1
Upper trace-Demodulated audio at 100 Hz, 100% modulation at 10kw, showing missing
step due to failed RF amplifier.
Lower trace-Modulation Encoder signal for missing step 20.
Figure 6-2
Upper trace-Demodulated audio for transmitter operating at 10kw, 125%+peak,
triangle modulation. Showing missing step 39.
Lower trace-Modulation Encoder signal for missing step 39.
6-14
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
It must be remembered that a 100% modulated signal at 11 kW
is NOT using all the the big steps. In fact Steps 36 through 42
are only ON during positive peaks. To check these steps, a
nonsymetrical audio waveform should be used in order to modulate the transmitter with a steady state tone at 125% positive peak
without causing overmodulation on the negative peak and therefore carrier shift. Figure 6-2 shows a non symmetrical ramp
modulating to 125% positive peak and only 50% negative peak.
An error is also shown near the top of the positive peak indicating
a big step failure at around Big Step 40. The modulation Encoder
waveform is also shown for that step.
Once the step causing the error is located the RF Amplifier can
be changed. If substituting the RF Amp does not remove the
error, then the problem may exist on the Modulation Encoder
board.
6.9.5 Transmitter Mistuning
The DX-10 will tune into a wide range of loads and still produce
very good audio performance. It could be possible for the transmitter load to be not optimized and therefore the transmitter will
not optimized into its load. Operate the transmitter at 10 kW into
the antenna system. Monitor the Antenna Null position on the
front panel multimeter. If the meter indication is not near zero,
adjust the Loading and tuning control for a minimum indication.
Operate the meter switch to the Bandpass filter position. The
meter indication should also be near zero. At this time the
transmitter is tuned properly.
6.9.6 Operating Into A Bandwidth Restricted An-
tenna
If the Distortion is poor especially at the higher audio frequencies
even when the transmitter is tuned properly, then the transmitter
may not be seeing a good load at the sidebands. Operate the
transmitter into a know good dummy load and if the higher
frequency distortion is lower, suspect the antenna system.
6.9.7 Mistuning Of The Bandpass Tuning Control
C101
This control is normally factory adjusted and requires no periodic adjustment. If an output network component has been
changed it may be necessary to adjust this. Normally the Bandpass tuning is adjusted for Peak RF output out of the transmitter
as indicated on the power meter. From there the control is
adjusted slightly off the peak in the inductive side. This is the
same as turning the control counterclockwise. This setting is
typically optimum for Efficiency, IPM and Mono THD and
IMD. The Bandpass tune can be adjusted while the transmitter
is on and modulating.
CAUTION
THE BANDPASS TUNING CONTROL SHOULD NOT BE ADJUSTED
MORE THAN 500W OFF OF THE POWER PEAK. MOST EFFICIENT
OPERATION OCCURS AT OR NEAR THE POWER PEAK. TUNING
OFF THE POWER PEAK IN THE CAPACITIVE DIRECTION COULD
CAUSE EXCESSIVE OVERHEATING OF THE RF AMPLIFIER
MODULES.
03/16/2009
6.9.8 Low RF Drive Level To The RF Amps
Low RF drive levels can cause higher than normal distortion.
Typically the RF drive on the RF Amps should be between 22
and 25Vp-p. To check the drive level see “Measuring RF Drive
Levels”
6.9.9 Additional Tips For Troubleshooting Audio
THD
If the Distortion problem cannot be found using the above means,
an excellent way to determine if the distortion is in the Analog
Input/A to D conversion process OR the Digital to Analog RF
Amplifier stages/Output network, is to measure the distortion out
of the Digital to Analog converter circuit for the Envelope Error
detector circuit. This sample is an actual reconstructed audio
sample of the Digital Audio. If any distortion is occurring in the
Analog input board, or in the Analog to Digital conversion
process, it will show up here. Connect a scope if the distortion
is visible on the audio waveform, or a distortion analyzer to J2
on the A to D board A34. Remove the BNC connector connected
to it. If the distortion is present here, troubleshoot the Audio
source, Analog input board, or the A to D converter. If the
distortion is not present, the distortion is occurring in the D to A
process and could be in the Modulation Encoder, RF Amps, or
Output Network.
6.10 Consistent Loss of RF Amplifier
Modules
Consistent loss of RF Amp modules refers to two types of losses.
The first kind would be the loss of different modules in the same
position such as step 6. The other type of consistent loss would
be of random module sections at various times. The DX-10 RF
Amp modules are very rugged and have a very long expected
life. Any type of consistent failure indicates something is wrong
with one of the following items in the transmitter.
6.10.1 Symptom: Consistent Loss of an RF Amp in
one Particular Slot.
Possible Causes
6.10.1.1 Improper RF Drive
The RF drive to the RF Amps must be between 20 and 26Vp-p
for proper operation. The phase of the drive must also be within
5 degrees of the other modules. To measure the drive amplitude
and phase, see “Measuring RF Drive Amplitude” and “Measuring RF Drive Phasing.” Causes of improper drive amplitude and
phasing are defective RF Amp, Defective Drive cable, or poor
motherboard connections.
6.10.1.2 Improper Drain Phasing
Just as the RF Drive must be within 5 degrees of the other
modules, the phasing of the switching waveforms on the drain
of the RF Amp MOSFET’s must also be in phase within 5
degrees. Even if the drive to the MOSFET’s is proper, other
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-15
problems can cause the drain phasing to be off. To measure the
Drain phasing, see “Measuring the RF Amp Drain Phasing.”
Causes of Improper drain phasing are poor connection or wrong
tapping of the efficiency coil for the RF Amp, a different MOSFET device installed compared to the others, or a defective
output toroid for the RF Amp.
6.10.1.3 Defective Output Toroid
The output toroid for each RF Amp must couple the RF output
of the Amp into the combiner. If the toroid is defective the Amp
will not operate efficiently. Check the toroid for cracks or signs
of arcing. Some inspection can be done through the holes in the
combiner cover but a more through inspection requires removal
of the combiner cover. See paragraph in the Maintenance section
on “Main Combiner/Motherboard replacement.
• It should be noted that many times an RF Amplifier that
fails due to wrong phasing will many times operate for a
short time before failure. During this condition the MOSFET devices on the module will operate Hotter than the
other modules. This is a good indication of a module
operating out of phase.
6.10.2 Symptom: Consistent Loss of Modules in Ran-
dom Positions
Possible Causes
6.10.2.1 A to D Phasing Improperly Set
An improperly set A to D phasing circuit will cause random
failures of RF Amps especially at the higher steps. See “A to D
Phasing Check” in the Maintenance section of the Manual.
6.10.2.2 Modulated B- Improperly Set
An improperly set Modulated B- can cause Random RF Amp
failures. See “Overall Modulated B-Adjustment” in the Maintenance section of the manual.
6.10.2.3 Improper VSWR Circuit Operation
If the VSWR protection circuit in not set properly random
failures RF Amps could occur during VSWR conditions. To test
the VSWR circuitry simply depress the front panel VSWR
SENSOR Manual Test Button. At that time both the Bandpass
Filter and Antenna VSWR LED’s should momentarily illuminate red the return to green. To check the threshold settings on
the VSWR Sensors, apply main power to the transmitter and
ensure that the low voltage is on. Measure the voltage at U1-5
(bottom of R12) on the Output Monitor board, and adjust
A27R15 so that the voltage indicates 2.25VDC. This sets the
Antenna VSWR trip threshold. Measure the voltage at U4-5 (top
of R20) on the Output Monitor board, and adjust A27R9 so that
the voltage indicates 2.30VDC. This sets the Bandpass Filter
VSWR trip threshold. The other VSWR circuit adjustments can
be checked by referring to paragraph on “OUTPUT MONITOR”
in the Maintenance section of the Manual.
6.10.2.4 Improper Setting Of The Oscillator Sync Circuit
This circuit is critical to the operation of the VSWR protection
and should be checked by referring to paragraph “OSCILLATOR SYNC ADJUSTMENT” in the Maintenance section of the
Manual.
6-16
6.10.2.5 Improper Overload Settings
If an Overload is improperly set or not working the RF Amplifiers could fail during an overload condition. Refer to paragraph
entitled “Overload Adjustment Procedures” in the Maintenance
section of the Manual.
6.10.2.6 Improper Air Flow
Normally insufficient air flow should be detected by the transmitter and an Air interlock should shut the transmitter off. If the
circuit is defective or defeated, overheating modules could cause
a premature failures.
6.10.2.7 Transmitter Mistuning
Transmitter mistuning could cause the RF Amplifier stage to run
inefficiently and therefore all the modules will run hotter. See
paragraphs “Transmitter Mistuning and Bandpass Tuning” in
this section of the Manual.
6.10.3 Symptom: Excessive Carrier Shift
Normally the DX-10 transmitter does not exhibit any type of
excessive carrier shift due to a specific problem such as power
supply sag. Typical problems with carrier shift are not caused by
the transmitter, but instead they are caused by DC offset and
Subaudible signals. Modulate the transmitter directly from an
audio generator. If the transmitter does not exhibit any carrier
shift with a direct tone look for a source of subaudible signals or
DC offset.
6.10.4 Symptom: Apparent poor Efficiency
The term apparent is used to describe an efficiency problem
because in many cases the apparent low transmitter efficiency is
caused by inaccurate measurement of the parameters used to
measure efficiency. The PA current, Supply Voltage, and Actual
power output should be re-verified before assuming the transmitter is operating inefficiently.
WARNING
ENSURE ALL VOLTAGE HAS BEEN REMOVED FROM THE
TRANSMITTER AND USE THE GROUNDING STICK TO GROUND
ALL POINTS WHERE AC OR RF POWER HAS BEEN APPLIED
BEFORE PROCEEDING WITH THE FOLLOWING PROCEDURE.
The best and quickest way to determine if the transmitter is
operating inefficiently is to feel how warm the RF Amps operate.
Typically the amps only run a couple of degrees above ambient
temperature when everything is operating normally. To check
the RF Amp heating operate the transmitter a 10 kW with normal
program modulation. Depress the Off button, quickly remove
power and open the inner front door. Starting with RF Amp Step
1, feel the cases of the two exposed MOSFET’s checking for any
module that appears to be running excessively warm. Only check
modules Steps 1-20 at this time. If all the modules are running
hot then there is a problem with efficiency. If one or two modules
are running hot the efficiency will be slightly lower. Those
modules that are running hot should be serviced. See “Consistent Loss of RF Amplifier Modules”
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Possible Causes of poor Efficiency
6.10.4.1 Transmitter Mistuning
The DX-10 will tune into a wide range of loads and still operate
very efficient. It could be possible for the transmitter load to be
not optimized and therefore the transmitter will not be optimized
into its load. Operate the transmitter at 10 kW into the antenna
system. Monitor the Antenna Null position on the front panel
multimeter. If the meter indication is not near zero, adjust the
Loading and tuning control for a minimum indication. Operate
the meter switch to the Bandpass filter position. The meter
indication should also be near zero. At this time the transmitter
is tuned properly.
6.10.4.2 Mistuning Of The Bandpass Tuning Control C101
This control is normally factory adjusted and requires no periodic adjustment. If an output network component has been
changed it may be necessary to adjust this. Normally the Bandpass tuning is adjusted for Peak RF output out of the transmitter
as indicated on the power meter. From there the control is
adjusted slightly off the peak, on the inductive side (counterclockwise). The correct amount of CCW (counterclockwise)
adjustment from the power peak is listed in the factory test data
as “C101 final tuning.” This setting is typically optimum for
Efficiency, IPM and Mono THD and IMD. If it is operated on
the capacitive side of resonance, poor efficiency will result. The
Bandpass tune can be adjusted while the transmitter is on and
modulating.
CAUTION
THE BANDPASS TUNING CONTROL SHOULD NOT BE ADJUSTED
MORE THAN 500W OFF OF THE POWER PEAK. MOST EFFICIENT
OPERATION OCCURS AT OR NEAR THE POWER PEAK. TUNING
OFF THE POWER PEAK IN THE CAPACITIVE DIRECTION COULD
CAUSE EXCESSIVE OVERHEATING OF THE RF AMPLIFIER
MODULES.
6.10.4.3 Low RF Drive Level To The RF Amps
Low RF drive levels can cause poor efficiency. Typically the RF
drive on the RF Amps should be between 22 and 25Vp-p. To
check the drive level see “Measuring RF Drive Levels”.
Figure 6-3
Pin identification of the MOSFET.
The MOSFET transistors are shipped in anti static packaging.
The transistors should remain in this packaging until they are to
be used or tested.
6.11.1.1 Testing MOSFET’s
The MOSFET’s used in the DX-10 transmitter may be checked
with an ohmmeter. However there is a requirement which restricts the use of some ohmmeters. If the battery voltage is too
low (under 3V) or too high (over 20V) the ohmmeter cannot be
used. A battery voltage less than 3V will not give an operational
check of the transistor and a battery voltage greater than 20V
may result in damage to the transistor under test. A Simpson 260,
which uses a 9V battery on the Rx10k scale works quite well.
The following test applies to all MOSFET’s used in the transmitter, but is not necessarily applicable to MOSFET’s used in
other equipment.
This test will show how a MOSFET can be switched “on” and
“off” by charging and discharging the gate of the MOSFET.
Refer to Figure 6-3 for the following test. Connect the positive
lead of the ohmmeter to the source of the transistor. Momentarily connect the negative lead to the gate and then connect it to
the source. Then connect the positive lead to the drain (case).
The ohmmeter should read at least 2 Megohms. Remove the
positive lead from the case and momentarily touch it to the gate.
Reconnect the positive lead to the case. The ohmmeter should
read very near zero ohms.
6.11.2 Using FlexPatch™ for Bypassing a Failed RF
Amp
6.11 Other Troubleshooting Techniques
6.11.1 Handling MOSFET’s
Due to the fragile nature of the gate of a MOSFET, special care
in their handling is required. The gate junction may be destroyed
by static electricity if the static electricity is allowed to discharge
through the MOSFET. For example, walking across a carpet to
pick up a MOSFET that is not protected by anti static packaging
could result in the destruction of the MOSFET. A static charge
could build up on a person as they walk across the carpet. This
static charge will eventually have to be discharged. Discharging
to the MOSFET could damage the MOSFET.
NOTE
MOSFET transistors which are in circuit are immune to this
damage.
03/16/2009
FlexPatch™ is a Harris feature to allow the engineer to patch a
failed RF Amplifier from an active step position such as step 6
to a step position that is only used for positive peak modulation
such as step 42. The fully operational module step 42 will now
operate as step 6. This patching is done on a low level basis and
can be done while the transmitter is on the air. If a Module fails
in Step 6 it is contributing to the power output and modulation
cycle of the transmitter. The power output of the transmitter will
drop around 10% and the THD will increase to around 2%. The
transmitter will operate fine in this condition but FlexPatch™
will allow the transmitter full power and optimum modulation
clarity with only a slight loss of positive peak capability.
To use the FlexPatch™ feature to bypass a failed RF AMP, first
determine the RF Amp to be patched. On the Modulation Encoder board, locate the gold jumper in the row of jumpers
running down the center of the board. Pull the jumper associated
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-17
with that step from the plug. Locate P6-3/4, the gold jumper for
step 42. Step 42 is selected because it is only on during the
highest positive peaks. Locate and remove one of the black wire
jumpers from their storage position on P8 on the Modulation
Encoder board. Connect one end of the FlexPatch™ Jumper into
the right hand hole of the jack of the failed RF Amp step. This
is the output drive signal of the modulation encoder for that step.
Next insert the free end of the FlexPatch™ cable into the right
hand side of the jack for step 42. This is the input to the modulator
section of the step 42 RF Amp. This completes the FlexPatch™
operation. If the power level was lower with the failed amp then
it should be normal now.
In conclusion, by using the Modulation Encoder schematic and
with careful thought it is possible to troubleshoot the circuitry
further with FlexPatch™ before attempting time consuming
substitutions or circuit measurements.
CAUTION
To remove the Supply voltage from the RF Amps, first remove
all primary power from the transmitter. Open the front door to
the power supply cabinet and locate the Fuse Board A24 on the
left hand hall of the power supply compartment. Now remove
fuses F1 through F7. Note that F1 and F3 are not the same values
as the others. Close the power supply cabinet and now open the
inner front door exposing the RF Amplifiers. Locate RF Amplifier Step 1 (bottom left RF Amp). Connect a X10 scope probe to
the left hand side of CR3 which is located in front of the heatsink.
Connect the probe such that the lead can be safely routed out the
interlocked door once it is shut, and the probe will not interfere
with the closing of the inner door. Connect the ground clip of the
probe to the edge of the front of the RF Amp card on either side
of the round hole in the front middle of the card. Note that this
is the ground plane for the RF Amp. Connect the probe to the
scope set up to measure an RF waveform at approximately
24Vp-p. Close the inner front door of the RF compartment and
apply primary power NOTE: A X10 SCOPE PROBE MUST BE
USED. ALSO ENSURE THAT THE SCOPE CASE IS PROPERLY GROUNDED.
WHEN USING FlexPatch™ WITH THE TRANSMITTER OPERATING, MAKE SURE THE FlexPatch™ CABLE IS INSERTED FIRST
INTO THE LEFT-HAND JACK OF THE MODULE TO BE SUBSTITUTED. THEN INSERT IT INTO THE JACK OF THE STEP 42 AMP.
THIS WILL PREVENT INADVERTENT TURN-ON AND POSSIBLE
FAILURE OF THE RF AMP SHOULD THE FlexPatch™ JUMPER
INADVERTENTLY TOUCH ANOTHER COMPONENT ON THE
MODULATION ENCODER BOARD.
Note that any number of FlexPatch™ Connections can be made
on the Modulation Encoder board. As more RF Amps need to be
substituted, the next lowest big step is selected. Example: Three
FlexPatch™ substitutions would use steps 40, 41 and 42 as the
substitute amps.
6.11.3 Using FlexPatch™ for Isolating Modulation
Encoder/RF Amp Problems
The FlexPatch™ feature can also be useful in determining where
a fault exists if the fault is not made apparent by an illuminated
LED on an RF Amp. For example during troubleshooting a
higher than normal distortion, it is discovered that on the demodulated audio signal a missing step is noted at step 6. See
paragraph “FINDING A MISSING STEP.” The LED on the Step
6 RF Amp module is not illuminated indicating that it is at fault.
The next step is to physically exchange it with a spare module.
It is found that this did not fix the problem and the fault still exists
at step 6.
The gold jumpers are now removed from the Modulation Encoder board for step 5 and step 6. Jumper the left hand side
(Encoder output) of the step 6 jack to the right hand side (RF
Amp input) of the step 5 jack. Connect the step 5 encoder output
(left) to the step 6 RF Amp input jack (right). See the Modulation
Encoder schematic 839-6208-088 sheet 1. Note on the schematic
that the RF Amp input side of the FlexPatch™ jacks does go
through some driver circuitry on the Modulation Encoder board.
After performing this patching, it is noted that the error on the
envelope now occurs at the step 5 interval and not step 6. This
indicates that the modulation encoder drive signal for step 5 that
is now going to the step 6 RF Amp through the Modulation
Encoder drive circuitry, is not operating. This says that the
Modulation Encoder drive circuitry for step 6 has failed. The
most likely suspect is U5-4.
6-18
6.11.4 Measuring RF Drive Level
This procedure can be used to measure the RF Drive levels on
the RF Amplifier modules. This should be done any time the
frequency is changed, a particular RF Amp is changed, or any
time problems are suspected to be caused by improper RF drive
level. Remember that there are two sections of each RF Amplifier module that have an individual drive signal fed into it.
Measure the RF Drive levels as follows.
Depress the LOW power on button and note that the high voltage
comes up as indicated on the front panel multimeter but no RF
power or PA current is indicated. With the scope DC coupled
note that an RF sine wave is now displayed on the scope. The
waveform should normally measure from 22 to 25Vp-p and it
should be centered on the 0.0VDC line of the scope. The drive
level may be lower than 20Vp-p at this time. If the waveform
falls totally below the 0.0VDC line of the scope, the step 1
amplifier is turned off. See Figures 6-4 and 6-5 for drive waveforms.
NOTE
When measuring RF Amplifier drive amplitudes or phasing, the
amplifier to be measured must be turned on to give a correct
drive measurement. The drive waveform of an “OFF” amplifier
will be below 0.0VDC and the peaks will probably be clipped
To turn on an amplifier first make sure that the PA TURN-OFF
switch on the Controller board is set to the PA-ON position. Next
depress the RAISE button until the desired amplifier turns on as
indicated by the correct drive waveform. Note that at 0 kW
output no Big step amps are on. As the power is raised the big
steps will successively turn on to increase the power output.
There are 42 Big step amplifiers, but even at 11 kW of carrier
power only Big step Amplifiers 1 through 18 will be turned on.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 6-4
RF drive waveform as seen at RF amplifier, Gate of Q3 (anode of CR7).
RF amplifier turned OFF (5V p-p per division).
Figure 6-5
RF drive waveform as seen at RF amplifier, Gate of Q3 (anode of CR7).
RF amplifier turned ON (5V p-p per division).
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-19
Therefore holding the raise button will only turn on up to step
18. To turn on any higher steps these must be manually turned
on using the Flex Patch feature discussed shortly.
Now that a measurement of the RF drive on step 1 has been made,
the RF Drive of any other RF Amp that needs to be measured
can be performed by repeating the above steps. Remember that
the left hand side of CR3 is the RF drive on the “A” side of the
amplifier and the right hand side of CR4 is the RF drive to the
“B” side of the amplifier. Note that to turn on the RF Amps Step
1-18 to measure drive, the transmitter can be operated on High
power and the raise button depressed until the amp turns on.
Remember to LOWER the power back down before turning off
the transmitter otherwise it may come back up at a higher than
expected power when the the fuses for the RF Amps are reinserted.
6.11.4.1 Measuring Steps 18-42
If the RF drive level is to be measured on an RF Amp from step
18 to 42, these must be manually turned on using the flex patch
feature. To do this remove the gold jumper from the FlexPatch™
plug for the desired step. The FlexPatch™ Panel is located on
the Modulation Encoder board. Remove any FlexPatch™
jumper cables from the holes in P8-1 and 2. P8 is located next to
the RF Amp test switch S2 on the Modulation Encoder board.
Now insert one end of a FlexPatch™ cable into P8-1. Connect
the other end of the jumper to the left hand hole of the jack where
the gold jumper was removed. Now operate the transmitter to
measure the drive of that RF Amp. Note that the drive waveform
will be clipped and below the 0VDC line because the RF Amp
is not turned on yet. Depress S2 and note that the drive level is
now turned on as indicated by a clean waveform equally above
and below ground. The drive amplitude of this RF Amp can now
be measured.
6.11.4.2 Measuring Binary RF Amp Drive Amplitude
Because the binary amps switch on at different rates, it is not
always possible to have all the binaries on at one time. To
measure the drive level of the 1/2 step for instance (B-7), the
power RAISE or LOWER can be held in until the module is
turned on as indicated by a drive waveform centered on the
0VDC line. This procedure can be repeated for the other binary
steps except the 1/16th (B10), 1/32nd (B11), and 1/64th (B-12).
These will normally tend to toggle from on to off making the
measurement difficult. These Amps and all the binaries can be
manually turned on with the FlexPatch™ feature described
above. To Manually turn on step B12 (1/64), place a flex patch
jumper from P8-1 to P9 near the top of the Modulation Encoder
board. S1 section 1 must be placed to the Off position otherwise
damage to the Modulation Encoder could occur. This turns off
the Modulation Encoder signal to B-12. Note that the drive signal
on B-12 is now OFF. Depress S2, RF Amp Test and note that the
module is now on as long as the button is depressed. This
procedure can be repeated for any binary amp.
6.11.5 Measuring Drive Phasing
This procedure can be used to measure the RF Drive Phasing on
the RF Amplifier modules. This should be done any time the
frequency is changed, a particular RF Amp is changed, or any
6-20
time problems are suspected to be caused by improper RF drive
phasing. Remember that there are two sections of each RF
Amplifier module and each have an individual drive signal fed
into them. Normally for proper transmitter operation, the drive
phasing on the RF amplifiers should be within +-4 degrees
maximum. Measure the RF Drive phasing as follows.
To remove the Supply voltage from the RF Amps first remove
all primary power from the transmitter. Open the front door to
the power supply cabinet and locate the Fuse Board A24 on the
left hand wall of the power supply compartment. Now remove
fuses F1 through F7. Note that F1 and F3 are not the same values
as the others. Close the power supply cabinet and now open the
inner front door exposing the RF Amplifiers. Locate RF Amplifier Step 1 (bottom left RF Amp). Connect a X10 scope probe to
the left hand side of CR3 which is located in front of the heatsink.
Connect the probe such that the lead can be safely routed out the
interlocked door once it is shut, and the probe will not interfere
with the closing of the inner door. Connect the ground clip of the
probe to the edge of the front of the RF Amp card on either side
of the round hole in the front middle of the card. Note that this
is the ground plane for the RF Amp. Connect the probe to the
scope set up to measure an RF waveform at approximately
24Vp-p. Close the inner front door of the RF compartment and
apply primary power.
NOTE:
A X10 SCOPE PROBE MUST BE USED. ALSO ENSURE THAT
THE SCOPE CASE IS PROPERLY GROUNDED.
Depress the LOW power on button and note that the high voltage
comes up as indicated on the front panel multimeter but no RF
power or PA current is indicated. With the scope DC coupled
note that an RF sine wave is now displayed on the scope. The
waveform should normally measure from 22 to 25Vp-p and it
should be centered on the 0.0VDC line of the scope. The drive
level may be lower than 20Vp-p at this time. If the waveform
falls totally below the 0.0VDC line of the scope, the step 1
amplifier is turned off. See Figures 6-4 and 6-5 for drive waveforms.
NOTE
When measuring RF Amplifier drive amplitudes or phasing, the
amplifier to be measured must be turned on to give a correct
drive measurement. The drive waveform of an “OFF” amplifier
will be below 0.0VDC and the peaks will probably be clipped
To turn on an amplifier first make sure that the PA TURN-OFF
switch on the Controller board is set to the PA-ON position. Next
depress the RAISE button until the desired amplifier turns on as
indicated by the correct drive waveform. Note that at 0 kW
output no Big step amps are on. As the power is raised the big
steps will successively turn on to increase the power output.
There are 42 Big step amplifiers, but even at 11 kW of carrier
power only Big step Amplifiers 1 through 18 will be turned on.
Therefore holding the raise button will only turn on up to step
18. To turn on any higher steps these must be manually turned
on using the Flex Patch feature discussed shortly.
6.11.5.1 Scope Setup
Set the scope on DC coupled, 5V per division, and the trace is at
center of the screen. Connect the external sync of the scope to
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
J5 on the oscillator board and make sure the scope sync is set to
External. Adjust the horizontal vernier on the scope so that one
full RF cycle occupies 9 divisions on the screen. Each division
now equals 40 degrees of phase shift. Using the Horizontal
positioning and triggering level on the scope place the zero
crossing of the waveform on the center crossing of the vertical
and horizontal lines of the scope. Increase the vertical sensitivity
of the scope to expand the waveform. Switch the scope to the
X10 position and readjust the horizontal position so that the RF
transition again crosses the center line of the scope. This will be
the reference for the phase measurements. If another Rf Amp
transition occurs at the first large division on the left, this
amplifier is operating at 4 degrees lagging from the reference.
See Figure 6-6.
Now that a reference phase has been established, without changing any of the scope settings, move the scope probe to the desired
RF Amp to be measured. It is usually a good idea to first measure
the drive phase of the Steps 1-6A then set your reference phase
to the module that is typical of the six. There may be 4 modules
operating at near the same phase and the other two may a few
degrees off. Again set the reference to the most common phase.
Also note that there will be some phase difference between the
A side and B side of the same module, but typically the A sides
of the RF Amps should all line up as well as all the B sides should
be within specifications. Typically there may be 2 to 4 degrees
difference between A and B sides and there should not be more
than +-4 degrees difference between all the A sides when referenced to an A side. +-4 degrees is also maximum phase difference between B sides when referenced to a B side.
6.11.5.2 Excessive Drive Phase Difference
If a module is out of specifications on drive phasing, first
substitute in a new module. If the module is the problem it is
most likely caused by a defective drive transformer, T1 or T2,
or a defective MOSFET Q1-Q4. Substitution is the only way to
troubleshoot this problem. If by changing the module the drive
phase is still not correct, the problem may be the drive cable. The
drive cable can be swapped with another temporarily to determine if it is the cable.
6.11.5.3 Measuring Steps 18-42
If the RF drive phasing is to be measured on an RF Amp from
step 18 to 42, these must be manually turned on using the flex
patch feature. To do this remove the gold jumper from the
FlexPatch™ plug for the desired step. The Flex Patch Panel is
located on the Modulation Encoder board. Remove any FlexPatch™ jumper cables from the holes in P8-1 and 2. P8 is located
next to the RF Amp test switch S2 on the Modulation Encoder
board. Now insert one end of a FlexPatch™ cable into P8-1.
Connect the other end of the jumper to the right hand hole of the
jack where the gold jumper was removed. Now operate the
transmitter to measure the drive of that RF Amp. Note that the
drive waveform zero crossing will not be visible because the RF
Amp is not turned on yet. Depress S2 and note that the drive
level is now turned on as indicated by a a zero crossing now
indicating drive phase. The drive phasing of this RF Amp can
now be measured.
03/16/2009
6.11.5.4 Measuring Binary RF Amp Drive Phasing
Because the binary amps switch on at different rates, it is not
always possible to have all the binaries on at one time. To
measure the drive phasing of the 1/2 step for instance (B-7), the
power RAISE or LOWER can be held in until the module is
turned on as indicated by a zero crossing of the the drive
waveform. This procedure can be repeated for the other binary
steps except the 1/16th (B10), 1/32nd (B11), and 1/64th (B-12).
These will normally tend to toggle from on to off making the
measurement difficult. The drive phase will appear to shift as the
module is toggling on and off. These Amps and all the binaries
can be manually turned on with the FlexPatch™ feature described above. To Manually turn on step B12 (1/64), place a flex
patch jumper from P8-1 to P9 near the top of the Modulation
Encoder board. S1 section 1 must be placed to the Off position
otherwise damage to the Modulation Encoder could occur. This
turns off the Modulation Encoder signal to B-12. Note that the
drive signal on B-12 is now OFF. Depress S2, RF Amp Test and
note that the module is now on as long as the button is depressed.
This procedure can be repeated for any binary amp.
6.11.6 RF Amplifier Drain Phasing
Even though the drive phasing to a particular amp may be within
limits, it is possible for the output phasing of that particular
amplifier to be out of specification and cause problems such as
module overheating and failure. Measurement of the drain phasing is only necessary when isolating a specific module problem.
The drain phasing of the Binary Amplifiers can be adjusted and
this is covered in the Maintenance section of the manual.
RF Amp drain phasing should be within +-4 degrees of each
other. Typical phasing is usually within +-2 degrees. Measure
the Drain phasing as follows.
WARNING
ENSURE ALL POWER IS REMOVED FROM TRANSMITTER AND
THAT GROUNDING STICK HAS BEEN USED TO DISCHARGE
ANY RESIDUAL POTENTIAL WHERE POWER HAS BEEN APPLIED ANY TIME THE INNER FRONT DOOR IS OPENED TO
ACCESS THE RF AMPLIFIER MODULES.
Open the inner front door of the transmitter and connect a X10
scope probe to the drain of Q3 on the Step 1 RF Amp. The drain
is the center pin of Q3 which is the left hand MOSFET on the
heatsink. Route the probe and cable on the scope such that the
inner front door can be closed. NOTE: A X10 SCOPE PROBE
MUST BE USED. ALSO ENSURE THAT THE SCOPE CASE
IS PROPERLY GROUNDED. Set the scope on AC coupled,
50V per division, and the trace to center of the screen. Connect
the external sync of the scope to J5 on the oscillator board and
make sure the scope sync is set to External. Operate the transmitter at 5 kW with no modulation. Adjust the horizontal vernier
on he scope so that on e full RF cycle occupies 9 divisions on
the screen Each division now equals 40 degrees of phase shift.
Using the Horizontal positioning and triggering level on the
scope place the zero crossing of the waveform on the crossing
between the center vertical and horizontal lines on the scope.
Increase the vertical sensitivity of the scope to expand the
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-21
waveform Switch the scope to the X10 position and readjust the
horizontal position so that the RF transition again crosses the
center line of the scope. This will be the reference for the phase
measurements. If another Rf Amp transition occurs at the first
large division on the left, this amplifier is operating at 4 degrees
lagging from the reference. See Figure 6-7.
phasing should be checked. The only other cause of drain phasing problems on a module would be the MOSFET’s themselves.
Substitution is the only way to troubleshoot this problem. If the
problem is not the module check the output toroid for that step
along with the efficiency coil L1 through L16 associated with
that step.
Now that a reference phase has been established, without changing any of the scope settings, move the scope probe to the desired
RF Amp to be measured. It is usually a good idea to first measure
the drain phase of the Steps 1-6A then set your reference phase
to the module that is typical of the six. There may be 4 modules
operating at near the same phase and the other two may a few
degrees off. Again set the reference to the most common phase.
Also note that there will be some phase difference between the
A side and B side of the same module, but typically the A sides
of the RF Amps should all line up as well as all the B sides should
be within specifications. Typically there may be 2 to 4 degrees
difference between A and B sides and there should not be more
than +/-4 degrees difference between all the A sides when
referenced to an A side. +/-4 degrees is also maximum phase
difference between B sides when referenced to a B side.
6.11.6.2 Measuring Steps 18-42
6.11.6.1 Excessive Drive Phase Difference
If a module is out of specifications on drain phasing, first
substitute in a new module. If the module is the problem the drive
6-22
If the RF Amp drain phasing is to be measured on an RF Amp
from step 18 to 42, these must be manually turned on using the
flex patch feature. To do this remove the gold jumper from the
FlexPatch™ plug for the desired step. The Flex Patch Panel is
located on the Modulation Encoder board. Remove any FlexPatch™ jumper cables from the holes in P8-1 and 2. P8 is located
next to the RF Amp test switch S2 on the Modulation Encoder
board. Now insert one end of a FlexPatch™ cable into P8-1.
Connect the other end of the jumper to the right hand hole of the
jack where the gold jumper was removed. Now operate the
transmitter at 5 kW. The reference phase should have already
been set as performed in the above steps. Note that the drive
waveform zero crossing on the module to be measured will not
be visible because the RF Amp is not turned on yet. Depress S2
and note that the drain is now turned on as indicated by a a zero
crossing now indicating drain phase. The drain phasing of this
RF Amp can now be measured.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure 6-6
RF drive waveform as seen at RF amplifier, Gate of Q3 (anode of CR7).
RF amplifier turned ON. Showing zero crossing of reference phase and the measured phase
approximately 1 degree lagging. 1 v p-p per division, X10 MAG.
Figure 6-7
RF drain waveform as seen at RF amplifier drain of Q3, RF amplifier turned ON.
Showing zero crossing of reference phase and measured phase
approximately 2 degrees lagging. 1V p-p per division, X10 MAG.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6-23
6-24
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section VIA
Emergency Operating Procedures
6.1 Introduction
This section of the technical manual contains information on
emergency operating procedures for the DX-10 transmitter.
In typical Broadcasting applications, it is desirable, if possible,
to keep on the air even if operation is at reduced power or with
reduced performance, until troubleshooting and repairs can be
made during a normal off air period.
The DX-10 transmitter has a number of safety and protective
devices and circuits, both for the protection of operating personnel and for protection of the transmitter. In some cases, the
transmitter can determine if continued operation is possible
following a failure. For some failures, the transmitter will remain
on the air; in other cases, it will reduce output power to a safe
level and remain on the air. For certain failures, the technician
or engineer can activate or substitute backup circuits either with
jumper plugs or with switches. This section will discuss some of
the do’s and don’ts of operation that should be followed should
any of the safety/protection devices or circuits be activated. The
Troubleshooting section of this Technical Manual contains information on locating faults; this section contains information
on Emergency action that may be taken once the fault is identified (for certain faults).
6.2 What to do if an Overload Occurs
When an overload occurs, one or more status indicators, on the
Status Indicator Panel on the front door of the transmitter should
indicate RED (instead of the normal green). The steps that should
be taken are:
a. The red status indications should be logged or recorded.
b. Push and release the RESET button on the status indicator
panel. When the RESET button is released, all status
indicators will remain green unless a fault is still present.
If one or more status indicators are still red, either the fault
must be corrected or, in some cases, appropriate emergency action may be taken to continue operation if desired.
Refer to Section VI of this Technical Manual for assistance.
c. If all Status indicators remain green after the RESET
button is released, depress the LOW, MEDIUM, or HIGH
pushbutton switch on the transmitter to turn the transmitter
back on.
d. If no further fault occurs, meter readings should be
checked for possible abnormal readings.
e. If a Power Supply Overcurrent overload, or a VSWR fault
(both indicated by the Status Indicator turning RED) occurs again, try operating the transmitter at reduced power.
Further information is given in paragraphs “High Voltage
Power Supply Overcurrent and VSWR Protection” and
03/16/2009
“Operation under High VSWR Conditions” of this section
for these two faults.
f. If the “RF AMP, ENVELOPE OK” status indicator is
RED, the modulation envelope is probably distorted. The
transmitter normally can continue to be operated on an
emergency basis, until the problem is found, if the distortion is acceptable. If the distortion is due to an RF amplifier
failure, refer to the paragraph on substituting another RF
amplifier section. Also see Troubleshooting, Section VI of
the manual, for more information.
g. If any other fault occurs, do not attempt to turn the transmitter on again. Locate and correct the problem first.
6.3 Power Supply Failure
If the high voltage (230 VDC) power supply, or the low voltage
power supply, or a voltage regulator on one of the PC boards
fails, corrective action will have to be taken before operation can
be restored.
If a power supply rectifier fails, the transmitter can not be
operated by simply removing the failed diode. This can cause
failure of the remaining diodes in the power supply. Removing
a diode will also increase the power supply ripple, causing a
sever degradation in the signal to noise ratio of the transmitter.
Another problem with this procedure will be increased heating
of, and possible damage to, the power transformer due to high
peak currents. Operating with any power supply diode removed
is not recommended, and is strongly discouraged by the manufacturer.
The Driver Supply Regulator utilizes a two stage linear regulator. During normal operation, only the first stage of the Driver
Supply Regulator is turned on. It is possible for that section to
fail and the second section will take over. A dramatic change in
the DRIVER SECT. 1A and DRIVER SECT 1B. readings will
be noted but no other change in the transmitter operation will
occur. If this condition is noted the Driver Supply Regulator
should be serviced as soon as possible. The transmitter will
operate in this Emergency position until then. DO NOT attempt
to adjust the Driver tuning control L2, during a Driver Supply
Regulator fault.
6.4 Crystal Failure
Crystal failures include complete failure to oscillate, low crystal
output, or oscillation off frequency. In case of crystal failure,
operation can be continued by using the other crystal. To accomplish this, use the following procedure:
a. Change crystals by moving the jumper in plug P1 on the
Oscillator board to the other position. (If the P1 jumper is
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6A-1
in position 1-2, change it to position 1-3. If the P1 jumper
is in position 1-3, change it to position 1-2.)
b. The crystal oven jumper P6 must also be changed. On the
oscillator board, change the P6 jumper so that it is in the
SAME position as the crystal jumper on P1. (Both must be
in position 1-2, or both must be in position 1-3).
NOTE
A small frequency shift (less than 50\Hz) may be due to the crystal oven not heating properly. This may be due to crystal oven
failure, failure of the -15 volt supply or regulator on the oscillator board, or having P1 and P6 installed in different positions.
which must be serviced. The transmitter will operate in this
Emergency condition until it can be serviced.
WARNING
DO NOT ATTEMPT TO CHANGE OVERDRIVE OR UNDERDRIVE
LIMIT SETTINGS OR THE OPEN OR CLOSED LOOP DRIVE LEVELS. IMPROPER DRIVE TO POWER AMPLIFIER SECTIONS MAY
CAUSE POWER MOSFET OR OTHER COMPONENT FAILURES.
6.8 VSWR Protection and Operation un-
der High VSWR Conditions
6.5 Predriver Amplifier Failure
The Predriver stage of the DX-10 consists of an RF Amplifier
module identical and completely interchangeable with any of the
Driver or PA RF Amplifiers. The RF Amplifier modules used in
the transmitter consists of two separate RF sections. In the
Predriver position only one half of the module is used to drive
the Driver stage. A toggle switch A14S1 on the Driver Combiner/Motherboard determines which half of the Predriver module is to be used. If the Predriver module fails the other half of
the Predriver can be selected by removing all power from the
transmitter, and removing the Predriver module. The selector
switch for the Predriver is located on the Driver Combiner/Motherboard in the area where the Predriver was removed. It can be
seen by looking into the area vacated by the module. Set the
switch to the other position and replace the Predriver module. If
a spare RF Amplifier is available it can replace the defective
module if desired.
A discussion of VSWR protection is included here to aid the
station technical and engineering staff in determining when
VSWR overloads may indicate a problem that should be located
and corrected. Emergency operating procedures are given first,
then a brief discussion of VSWR protection and possible causes
of VSWR faults is included.
The VSWR protection built into the DX-10 transmitter is both
for the protection of transmitter high power circuitry and the
protection of external equipment which might be installed between the transmitter and the antenna system. Operating at high
power with a VSWR condition can result in high voltages or
currents in transmitter circuitry, or in circuits and equipment
between the transmitter and the antenna, or in antenna impedance matching and coupling circuits. High voltages or currents
can result in arcing, overheating of components, or component
failure. In general, the VSWR overloads and limits set in the
transmitter’s protection circuitry should not be bypassed or
increased beyond the recommended limits set at the factory.
CAUTION
6.6 High Voltage Power Supply Overcur-
rent
If supply overcurrent faults occur with high level modulation,
and supply current is not excessive, then reducing modulation
level and/or reducing transmitter power output may permit continued operation until the transmitter can be shut down to locate
and correct the problem.
6.7 RF Overdrive or Underdrive
If the problem is a Predriver problem, refer to the “Predriver
Failure” paragraph above. If the problem is due to an Underdrive
Overload, note if any of the Driver module faults LED’s illuminate as soon as the high voltage is applied. If this does occur,
then replace that Driver module. If no module fault indicators
illuminate, the problem may be due to a Driver Supply Regulator
problem. Locate the three access holes above the Oscillator
board which allow access to the Driver Supply Regulator Adjustments. With an insulated tool set the LOOP Select switch
A22S1 to the OPEN LOOP position. If the transmitter now
operates, there is a problem with the Closed Loop regulator
6A-2
VSWR overload limit settings that exceed recommended values may result
in component damage or failure.
6.9 Emergencvy Operating Procedures
for Antenna VSWR Overload
If the ANT VSWR status indicator stays RED, and the DX-10
has reduced its power output, but the antenna system is still
radiating a signal and the reflected power meter indicates some
power level, then something has caused an impedance change in
the transmitter load. Emergency Action that may be taken to
continue operation includes the following steps:
a. If possible, reduce the reflected power meter reading with
the TUNING and LOADING controls. If the load impedance change is not too great, it will be possible to compensate for it with these two controls.
b. Depress the Reset button on the front panel to extinguish
the VSWR fault indicator(s). If reflected power can be
reduced with the tuning and loading controls, the transmitter output power may be increased until the VSWR lamp
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
flashes on again (or normal operating power is reached, if
that occurs first). Reduce power output slightly so that the
VSWR lamp does not come on.
c. The transmitter may be operated at reduced power until
the cause of the impedance change is located and corrected.
WARNING
DO NOT BYPASS OR ADJUST VSWR PROTECTION CIRCUITRY.
OPERATION WITH EXCESSIVE REFLECTED POWER MAY RESULT IN COMPONENT FAILURE, OR HIDDEN DAMAGE TO COMPONENTS, IN THE TRANSMITTER OR TO EQUIPMENT BETWEEN
THE TRANSMITTER AND THE ANTENNA.
If only the BANDPASS FILTER VSWR status indicator stays
red, and the DX-10 has reduced its output power, but the Reflected Power meter indication is low, a change in the transmitter
output network or the VSWR phase detector is indicated. To
continue EMERGENCY OPERATION until the fault can be
located and repaired:
a. Do NOT attempt to raise power.
b. Do NOT change tuning or loading controls.
c. The transmitter may be operated at reduced power until
the fault can be located and repaired when programming
schedules permit.
for a short period a number of times, the transmitter will reduce
power. This power reduction might be compared to the “VSWR
Foldback” used in some FM transmitters, where power is reduced until a power level is reached where safe operation can
continue.
The phase detectors act very quickly, in much less than a millisecond, to detect a VSWR fault and turn off the transmitter RF
output for approximately 20 milliseconds or less. The VSWR
status indicator flashes red for approximately one-half second,
then returns to green. If the VSWR condition is still present,
when the transmitter power output returns, this action will be
repeated. If enough VSWR faults occur in succession, in a short
period of time, the transmitter control circuitry will produce an
internal command to reduce power. Power reduction will continue until the reflected power is below the VSWR overload
circuit limit setting.
If power reduction has occurred, as described in the paragraph
above, the VSWR status indicator will remain RED, and a
“TYPE 3 FAULT” remote status output will occur.
When a VSWR condition occurs, high voltages and currents may
occur in RF circuitry. Reducing transmitter power output can
reduce these to safe levels, so that operation can continue temporarily on an emergency basis.
6.11 Possible Causes of VSWR Overloads
6.10 DX-10 VSWR Protection Circuit Ac-
tion
The DX-10 has a factory-tuned output network, following the
PA, which is a bandpass filter and provides impedance matching.
The output of this output network is 50 Ohms. The Forward and
Reflected Power directional couplers, and an Antenna VSWR
Phase detector, are located at this 50 Ohm impedance point. An
additional Bandpass Filter Phase Detector detects changes in the
output network.
Many stations will have a load that is not exactly 50 + j0 Ohms.
Also, antenna impedance may change somewhat with changing
weather conditions at some installations. The DX-10 transmitter
has a built-in impedance matching network between the 50 Ohm
point and the transmitter output terminal, to allow these loads to
be compensated for. This impedance matching network is a
“TEE” network, with two adjustments, which are labeled “Tuning” and “Loading.” Because these adjustments are located after
the directional coupler in the RF signal path, they will also cause
the reflected power meter reading to change, and mistuning may
cause VSWR overloads.
Most VSWR faults can be cleared by simply causing the transmitter power output to go to zero for a brief period of time. In
the DX-10, this zero power output is accomplished by turning
all PA sections off through modulator action. This occurs so
quickly (less than 15 milliseconds) that it may not even be
noticed by listeners, or will be simply a slight “click” or “pop.”
If a VSWR fault cannot be cleared by turning the transmitter off
03/16/2009
VSWR overloads during stormy weather may occur normally,
and may be no cause for concern. Proper installation of static
drain and static discharge equipment in the antenna system can
minimize, but not eliminate, this problem.
Causes of VSWR overloads may be listed in three categories.
They will first be listed, then will be discussed in more detail in
the following paragraphs.
a. Arcing in the impedance matching network, phasor,
switching equipment, transmission line, impedance
matching or tuning equipment, or at the tower ball gaps.
Once an arc occurs, transmitter output power will probably
sustain the arc. When the transmitter power output is
removed, the arc will go out (unless there is some other
voltage source to keep it going).
b. Transients or other signal pickup, fed back into the transmitter output from the antenna system.
c. Component failures causing a change in load impedance
at the transmitter output connector.
6.11.1 Common causes of Arcing
a. Static discharge or discharge due to lightning, across ball
gaps, guy wire insulators, or possibly across components
already operating close to their voltage ratings. Static
charge buildup can occur on towers that do not have
provision made for static discharge, such as static drain
chokes. Charge buildup can also occur on insulated guy
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6A-3
wire segments. Static charge buildup can occur under
conditions of rain, snow, or even blowing dust or sand.
b. Dirt build up or moisture (including condensation) on
insulating surfaces, causing the voltage breakdown rating
to be reduced. VSWR overloads will probably occur on
modulation peaks.
c. Condensation inside a transmission line may cause reduced breakdown voltage of the line. This can occur if
pressurized gas filled lines lose pressure or if the dehydrator in the line pressurization unit fails. VSWR overloads
will probably occur on modulation peaks.
d. In new systems, insufficient voltage rating of components,
such as capacitors or insulators, or spark gaps that are set
too close.
Transient signal pickup may occur during thunderstorms, even
from distant lightning strokes in some cases. Lightning strokes
may induce currents in towers, causing currents on the transmission lines that can reach the phase detectors and give a VSWR
overload indication.
Other nearby stations’ signals can also induce voltages and
currents in antenna systems that are large enough to be detected
by the phase detector and cause VSWR overloads. The solution
in such cases may be a trap or filter in the antenna impedance
matching network or phasor.
6.12 Load Impedance Changes
The Reflected Power reading and Antenna Null position on the
front panel multimeter is the best indication of the antenna
operating impedance once initially tuned into the antenna. If the
Reflected Power and Antenna null indications change this indicates an impedance change of the transmitter load.
If the LOADING and TUNING controls do not have enough
range to tune for a reflected power meter null or minimum, a load
impedance that is substantially different from 50 + j0 Ohms is
indicated.
If an impedance change, as described above, occurs, the load
impedance should be checked with proper impedance measuring
equipment, and the improper load should be corrected if possible.
“Dummy loads” should also be treated with caution. Dummy
load resistance or impedance may change with time, and dummy
load resistance or impedance may also change as the load heats
up when power is applied. If reflected power changes for a time
after power is applied to the load, this is probably the cause.
The impedance matching TEE network contains only three
inductors and two parallel capacitors. Changes in these components is possible, but not likely. The antenna system impedance,
or dummy load impedance, should be carefully checked before
assuming the problem is in the DX-10 impedance matching
network.
6A-4
Changes in component values in the DX-10 directional coupler
or phase detector circuits is also possible, but not likely. These
types of circuits have been very stable and reliable. Checking or
adjusting these circuits requires impedance measuring equipment that is known to be accurately calibrated.
6.13 RF Amplifier Failure (Failure of PA
Sections)
A procedure for bypassing a failed PA RF amplifier section is
given below. Some additional information on PA failures and on
locating faulty sections will be given first.
6.13.1 Power Amplifier Description
The power amplifier consists of 48 identical RF Amplifier
modules. Six of these modules are used as “Binary” Amplifiers,
designated B-7 through B-12. The remaining 42 RF Amplifiers
are referred to as the Big Step amplifiers. The transmitter symptoms will vary depending on the location of the failed RF
Amplifier module. In almost all cases, a failure of an RF Amplifier will produce a higher audio distortion but it may not be
audible or objectionable until more than one RF Amplifier fails.
A failed Big Step amplifier located in a critical position that
produces a lower power output and some distortion can be
actively bypassed for an operating RF Amplifier located in a
non-critical position that would only produce distortion on positive peaks. The Binary Step amplifiers cannot be bypassed, but
failure of a Binary Step will result in a smaller distortion increase.
6.13.2 Indications of PA RF Amplifier Failure
The most likely indication of a PA RF amplifier failure is a RED
indication on the “RF AMP, ENVELOPE OK” status indicator.
PA RF Amplifier failure will cause some increase in audio
distortion, and a small “step” or notch can be observed when a
sine wave modulated RF output waveform is observed on a good
quality oscilloscope. The distortion increase will normally be
under 2% for one failed RF Amplifier. If desired, the faulty
amplifier may be bypassed, without turning the transmitter off,
by using the FlexPatch*TM feature on the Modulation Encoder
board, which is described below.
A failed PA will not cause further damage to the transmitter, if
the failed module and any failed power transistors (power MOSFET’s) are simply left in the transmitter.
WARNING
DO NOT OPERATE THE TRANSMITTER WITH ANY PA MODULES
OR POWER MOSFET DEVICES REMOVED. SUCH OPERATION
MAY DAMAGE FERRITE CORES IN THE COMBINER TOROIDS OR
CAUSE OTHER COMPONENT DAMAGE.
6.13.3 Identifying Failed PA RF Amplifiers
Each RF Amplifier module consists of two half sections, each
with a individually fused supply and fault indicator. When a
power MOSFET shorts, or some other amplifier components
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
fail, a fuse associated with that half (two PA MOSFET’s) will
open (blow), and a red LED fuse indicator will light. These red
LED indicators are visible through the openings in the inner front
door, which is visible once the center front non-interlocked door
is opened. The RF amplifier which has failed may be identified
by noting which amplifier step number is labeled on the inner
front door next to the fault LED. The Big Steps are simply
labeled 1-42 while the Binary amplifiers are labeled B7-B12.
These numbers correspond with numbers next to the jumper
plugs on the Modulation Encoder board.
There are RF amplifier faults which will not cause a fuse to open
(blow). These include failure of the small “modulator” transistors and associated components. In this case, a dual trace oscilloscope may be used to locate the fault. A procedure is described
in the Troubleshooting section of this Technical Manual, and is
summarized in the next paragraph.
To locate a PA RF amplifier failure using an oscilloscope, the
transmitter must be modulated to 100% with a sine wave (100Hz
to 1 kHz). One channel of the oscilloscope is used to observe the
modulated RF output of the transmitter, and the other is used to
observe the pulse outputs present on the jumpers on P1 through
P6 on the Modulation Encoder board. A small step or error
should be observed on the modulated RF waveform when a fault
exists. A pulse with a width that corresponds to, or just “fits in”
the step on the modulated waveform will be found on one of the
jumpers (1 through 42) on P1 through P6. The number of that
jumper corresponds to the number of the Amplifier that has
failed, and when that quad is bypassed using the procedure
below, the “step” in the waveform should disappear. (If it does
not, try bypassing the jumpers immediately above and immediately below, as there may be some uncertainty in reading the
oscilloscope display). Again see the Troubleshooting section of
the manual for more detailed information on “Locating a Missing
Step.”
6.13.4 Substituting for Failed Power Amplifier Sec-
tions
P1 through P6 on the Modulation Encoder Board, A36, may be
used to “bypass” a failed PA RF amplifier. P7 is not used on the
DX-10, and is not installed on the printed circuit board. Positions
43 through 48 on P6 are also not used on the DX-10.
The “RF amplifier turn on” signals to the power amplifier
sections are all routed through the jumpers on P1 through P6.
Numbers printed on the PC board next to each jumper correspond to RF amplifiers 1 through 42. When any jumper is
removed, the corresponding PA RF Amplifier is turned off. If an
RF Amplifier has failed, the turn-on signal for it may be routed,
using a jumper, to another available RF Amplifier. The highest
03/16/2009
numbered amplifiers will be active only on high level positive
modulation peaks, and then only if the maximum transmitter
power of 11 kilowatts is used. By using one of these to substitute
for a faulty amplifier, a slight loss in positive peak capability
could result in some cases (when 11 kW or nearly 11 kW is
required to overcome antenna system losses).
If an RF Amplifier fails, a good rule of thumb to follow when
determining if a failed amp should be substituted is; If the failed
RF Amplifier is located in step 1-20, it probably is causing
slightly reduced power and some distortion. It should be substituted for optimum transmitter operation. If the failed RF Amplifier is located in step 21-42, it is only affecting distortion at
higher modulation and power levels. If the distortion is not
noticeable then the transmitter can operate in this condition until
it can be turned off to replace the module. The failed RF Amplifier can be substituted if desired. If any RF Amplifier fails and
it is desired to substitute it until it can be replaced the following
procedure can be used.
a. Remove the U-shaped jumper for the failed position from
P1 through P6.
b. Remove the U-shaped jumper from position 42 of P6. (If
a wire jumper is already routed to position 42, remove the
U-shaped jumper from position 41, or from the highestnumbered available position.)
c. Install a jumper from the LEFT side of the failed position
(the position where the jumper was removed in step “a”),
to the RIGHT side of position 42 (or the position used in
step “b”). These steps substitute RF amplifier number 42
(or the position used in step “b”) for the one that failed.
d. A long wire jumper is installed between the LEFT side of
position 43 and single jack P15. Remove the end that is
plugged into position 43 and plug it into the LEFT side of
position 42 (or the position used in step “b”).
WARNING
WHEN USING FlexPatch™ WITH THE TRANSMITTER OPERATING, MAKE SURE THE FlexPatch™ CABLE IS INSERTED FIRST
INTO THE LEFTHAND JACK OF THE MODULE TO BE SUBSTITUTED. THEN INSERT IT INTO THE JACK OF THE STEP 42 AMP.
THIS WILL PREVENT INADVERTENT TURN-ON AND POSSIBLE
FAILURE OF THE RF AMP SHOULD THE FlexPatch™ JUMPER
INADVERTENTLY TOUCH ANOTHER COMPONENT ON THE
MODULATION ENCODER BOARD.
e. This completes the procedure. When the faulty RF amplifier has been repaired, the procedure may be reversed to
restore all jumpers to their original positions.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
6A-5
6A-6
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section VII
Parts List
Replaceable Parts List Index
Table 7-1.
Table 7-2.
Table 7-3.
Table 7-4.
Table 7-5.
Table 7-6.
Table 7-7.
Table 7-8.
Table 7-9.
Table 7-10.
Table 7-11.
Table 7-12.
Table 7-13.
Table 7-14.
Table 7-15.
Table 7-16.
Table 7-17.
Table 7-18.
Table 7-19.
Table 7-20.
Table 7-21.
Table 7-22.
Table 7-23.
Table 7-24.
Table 7-25.
Table 7-26.
Table 7-27.
XMTR, DX-10 10KW SS MW . . . . . . . . .
RF MODULE . . . . . . . . . . . . . . . .
MOD KIT FOR 480V CONVERSION . . . .
XMTR, BASIC, DX-10 10KW . . . . . . . . .
THERMAL INTERLOCK . . . . . . . . . .
MODULATION ENCODER . . . . . . . . .
PWA, FUSE
ESD SAFE . . . . . .
*PWA, ANALOG TO DIGITAL CONV . . .
PWA, MULTIMETER/PROBE,ESD SAFE .
DC REGULATOR . . . . . . . . . . . . .
*PWA, DX SWITCH, . . . . . . . . . . . .
PWA, OUTPUT SAMPLE . . . . . . . . .
PWA, EXTERNAL INTERFACE . . . . . .
LED BOARD . . . . . . . . . . . . . . . .
CONTROLLER . . . . . . . . . . . . . . .
PWA, PWR DISTRIBUTION,ESD SAFE . .
PWA, SPLITTER, RF, ESD SAFE . . . . .
BUFFER AMPLIFIER . . . . . . . . . . .
COMB/MOTHERBD DRIVER, ESD SAFE .
COMB/MOTHERBD BINARY, ESD SAFE .
PWA, COMB/MOTHERBD, ESD SAFE
PWB, DRIVER SUPPLY REG . . . . . . .
OSCILLATOR . . . . . . . . . . . . . . .
ANALOG INPUT BOARD . . . . . . . . .
POWER SUPPLY DISCHARGE . . . . . .
OUTPUT MONITOR . . . . . . . . . . . .
XMTR, DX-10 10KW SS MW . . . . . . . . .
Table 7-28
PWA, OSCILLATOR (alternative to 992 8069 002)
12/09/04
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
994 9085 001
992 6967 001
992 9733 001
994 9085 002
917 2165 001
992 6509 002
992 6675 001
992 6730 003
992 6752 005
992 6783 001
992 6784 002
992 6786 001
992 6827 001
992 6828 001
992 6881 001
992 6916 002
992 6958 001
992 6969 001
992 6970 001
992 6971 001
992 6972 001
992 6973 001
992 8069 002
992 8077 002
992 8684 004
992 9298 001
994 9085 003
7-2
7-3
7-4
7-4
7-9
7-9
7-11
7-11
7-14
7-14
7-16
7-17
7-17
7-18
7-21
7-24
7-24
7-24
7-25
7-26
7-26
7-27
7-28
7-29
7-32
7-32
7-34
. . . . . 992 8069 004
7-35
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-1
Table 7-1. XMTR, DX-10 10KW SS MW - 994 9085 001 (X)
Harris PN
0411310013A
300 1977 000
306 0011 000
312 0053 000
500 0452 000
500 0458 000
500 0852 000
500 0911 000
500 1321 000
500 1322 000
500 1323 000
500 1324 000
500 1325 000
504 0353 000
504 0374 000
504 0377 000
504 0378 000
504 0382 000
504 0418 000
504 0419 000
504 0420 000
504 0433 000
504 0435 000
504 0454 000
504 0461 000
504 0462 000
504 0463 000
504 0496 000
504 0497 000
514 0240 000
514 0264 000
514 0266 000
516 0207 000
516 0208 000
516 0209 000
516 0210 000
516 1016 006
516 1016 008
516 1016 014
516 1025 000
540 1167 000
540 1490 000
646 1353 000
813 5611 139
817 0914 253
817 1280 025
829 9009 226
829 9009 227
839 6208 241
839 6208 250
839 6208 251
839 6208 256
839 6208 264
7-2
Description
*RUBBER SPONGE 3/8
SCR, 3/8-24 X 1/2
NUT, STOP 6-32
WASHER, SPLIT-LOCK 3/8
CAP .002UF 10% 2500V
CAP .01UF 10% 1200V
CAP, MICA, 1000PF 500V 5%
CAP, MICA, 750PF 500V 5%
CAP. .001UF 10% 2500V
CAP .005UF 10% 1200V
CAP .02UF 10% 600V
CAP .004UF 10% 2500V
CAP .003UF 10% 2500V
CAP 3000PF 12KV 5% (293)
CAP 2000PF 15KV 5% (293)
CAP 1500PF 15KV 5% (293)
CAP 1200PF 15KV 5% (293)
CAP 2400PF 12KV 5% (293)
CAP 2700 PF 12KV 5% (293)
CAP 3300 PF 12KV 5% (293)
CAP 3900 PF 12KV 5% (293)
CAP 3600PF 12KV 5% (293)
CAP 5600PF 10KV 5% (293)
CAP 1600PF 15KV 5% (293)
CAP 1300PF 15KV 5% (293)
CAP 1800PF 15KV 5% (293)
CAP 2200PF 12KV 5% (293)
CAP 4700PF 10KV 5% (293)
CAP 6200PF 10KV 5% (293)
CAP, VAR 2300PF 15KV TEST
CAP, VAR 1500PF 30KV TEST
CAP, VAR 1500PF 40KV TEST
CAP, RF, 25PF 15KV 10% NPO
CAP, RF, 50PF 15KV 10% NPO
CAP, RF, 100PF 15KV 10% N750
CAP, RF, 200PF 7.5KV 10% N750
CAP HV 1500PF 14 KV 5% CUSTOM
CAP HV 1000PF 14KV 5%
CAP HV 350PF 20KV 5% NP0
CAP HV 500PF 20KV 5%
RES 5.0 OHM 275W 10%
RES 10.0 OHM 275W 10%
NAMEPLATE, XMTR EQUIPMENT
STUD SPEC
STRAP, .020 X 1.0 X 6.4IN
SPEC, 5PPM CRYSTAL, AM RADIO
SHAFT, VAR CAP ADJ
SHAFT, VAR CAP ADJ
SCHEM, OVERALL
CAP CONTACT RING
TWO CAP CONTACT PLATE
QUAD CAP CONTACT PLT
CABINET OUTLINE, DX10
QTY UM
22.0 FT
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
0
EA
1.0
0
0
0
0
0
0
0
0
0
0
Reference Designators
A14C12,C13,C14
C038
A014C003,A014C004 1501 KHZ TO 1600 KHZ
A014C003,A014C004 1601 KHZ TO 1720 KHZ
A14C12,C13,C14
A14C12,C13,C14,C38
C38
A14C12,C13,C14
A14C12,C13,C14
C103,C104
C104
C104
C104
C104
C104
C104
C102,C104
C102,C104
C102
C104
C104
C104
C104
C103
C102
C101
C101
C101
C105
C105
C105
C105
C103
C102,C103
C102
C102
R38
R38
#C102
#C105
#C101
#C101
#C101
#C102
#C103
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
839 6208 285
839 8222 078
917 2131 042
939 8220 296
939 8220 298
939 8220 299
943 5479 110
943 5479 112
943 5479 113
943 5479 114
943 5479 115
988 2247 001
989 0042 001
992 6967 001
992 9733 001
994 9085 002
999 2590 001
CHART, TUNING, DX10
FD CHART, DX-10
CE KIT, DX-10/15
PLATE, CAP CONNECTING
PLATE, CAP MTG.
PLATE, CAP MTG.
CONTACT RING, CAPACITOR
BRACKET, CAP MTG
STRAP, CAPACITOR
BRACKET, -013 CAPACITOR
STRAP, -013 CAPACITOR
DP DX-10 MAINTENANCE
PKG CHECK LIST, DX-10
RF MODULE
MOD KIT FOR 480V CONVERSION
XMTR, BASIC, DX-10 10KW
HARDWARE LIST
Harris PN
000 0000 003
328 0071 000
380 0125 000
380 0126 000
380 0681 000
384 0802 000
384 0803 000
384 0810 000
384 0817 000
398 0449 000
402 0194 000
410 0413 000
494 0214 000
494 0398 000
500 0759 000
500 0784 000
500 0787 000
506 0235 000
508 0412 000
508 0537 000
508 0549 000
516 0419 000
540 1600 203
540 1600 419
546 0295 000
548 2400 130
548 2400 209
548 2400 566
839 6208 246
843 4038 100
929 9009 198
939 6208 289
939 6208 290
Description
FREQUENCY DETERMINED PART
WASHER, STEEL COMPRESSION
XSTR, NPN 2N4401 ESD
XSTR, PNP 2N4403 ESD
XSTR IRFP350 ESD
TRANSZORB, BIPOLAR 18V 5% ESD
RECT MUR-120 200V ESD
LED, RED, T1, RT ANG ESD
RECT, SCHOTTKY, CRSH2-3 ESD
FUSE 1TIME MIDGET 3A 250V
CLIP FUSE BRONZE
THERMAL INTERFACE, TO-247
CHOKE RF 1.8UH
CHOKE RF 10.0UH +/- 10%
CAP, MICA, 100PF 500V 5%
CAP, MICA, 300PF 500V 5%
CAP, MICA, 200PF 500V 5%
CAP .0033UF 100V 5%
CAP .047UF 200V 5%
CAP .047 UF 600WVDC 5%
CAP .33UF 5% 400VDC
CAP .05 UF 500V
RES 120 OHM 3W 5%
RES 56K OHM 3W 5%
RES 50 OHM 3.25W 5%
RES 20 OHM 1/2W 1%
RES 121 OHM 1/2W 1%
RES 475K OHM 1/2W 1%
SCHEM, RF MODULE
PWB, RF MODULE
XFMR
HEATSINK
HEATSINK
0
0
0
0
0
0
0
0
0
0
0
1
0
1.0
0
1.0
1.0
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
#C103
#C103
#C103
#C101
#C102
#C102
#C102
#C102
SPARE
Table 7-2. RF MODULE - 992 6967 001
12/09/04
QTY UM
0.0 EA
4.0 EA
1.0 EA
2.0 EA
4.0 EA
4.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
4.0 EA
4.0 EA
2.0 EA
2.0 EA
0.0 EA
0.0 EA
0.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
2.0 EA
2.0 EA
0.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
Reference Designators (T)
L005
#Q001 #Q002 #Q003 #Q004
Q007
Q005 Q006
Q001 Q002 Q003 Q004
CR001 CR002 CR003 CR004
CR007 CR008
DS001 DS002
CR005 CR006
F001 F002
2#F001 2#F002
#Q001 #Q002 #Q003 #Q004
L001 L002
L003 L004
C009 C010
C009 C010
C009 C010
C005 C006
C007
C008
C001 C002
C003 C004
R003 R004
R001 R002
R005 R006
R009
R007 R008
R010 R011
T001 T002
#Q001 #Q002
#Q003 #Q004
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-3
Table 7-3. MOD KIT FOR 480V CONVERSION - 992 9733 001
Harris PN
472 1764 000
560 0077 000
817 2494 002
839 8118 602
917 2494 001
Description
XFMR POWER, SPEC 843-5293-434
MOV, 275WVAC, 400J, 40MM DISC
MOD INSTR, 440-480 VAC 3PH
SCH, OVERALL, 3PH, DX10, WYE
JUMPERS, MOD KIT
QTY UM
1.0 EA
5.0 EA
0.0 EA
0.0 EA
1.0 EA
Harris PN
007 4060 060
026 6010 003
0311810015A
0416030010A
2960344000A
296 0348 000
302 0551 000
304 0039 000
304 0166 000
354 0894 000
356 0094 000
356 0110 000
357 0067 000
358 0003 000
358 0437 000
358 0498 000
358 0960 000
358 2426 000
358 2511 000
358 2588 000
358 2589 000
358 2598 000
358 2635 000
358 3109 000
358 3121 000
358 3123 000
Description
BRZ, FGR STK OC97-438-04
GROMMET STRIP, 0.125
*GSKT, .125 X .500
*RUBBER CHANNEL X650
*TUBG, POLYETHYLENE 1/4 OD
TUBG,POLYETHYLENE 3/8 OD
SCR, SOC HD SHOULDER
NUT CAP .312-18 BRS
NUT, SQ. BRASS, 1/4-20
LUG, ADAPTER, SPADE, 0.187
ADHESIVE CABLE CLIP
CABLE CLAMP 3/4 D
NUT, ACORN CAP 10-32
BRACKET RESISTOR MTG
BUSHING PANEL .252 ID
CLAMP, HOSE
CPLR, 1/4"X1/4" SHAFT
PLUG, WHITE 2" HOLE
STANDOFF, 10-32 X 3/4
FLAT CABLE MOUNT
FLAT CABLE MOUNT
CABLE TIE MOUNT, 4-WAY
CABLE TIE, PUSH MOUNT SNAP IN
STUD, BRS 8-32 X 1
STUD, BRS 10-32 X 1
STUD, BRS 10-32 X 1-1/2
QTY UM
1.0 FT
4
ME
10.0 FT
1.0 FT
6
FT
0
FT
2.0 EA
2.0 EA
2.0 EA
4
EA
1.0 EA
1
EA
6.0 EA
8.0 EA
2.0 EA
12.0 EA
2.0 EA
4.0 EA
2.0 EA
1.0 EA
10.0 EA
3.0 EA
30.0 EA
4.0 EA
2.0 EA
9.0 EA
358 3134 000
358 3300 000
358 3301 000
358 3660 000
359 1199 000
384 0702 000
384 0839 000
384 0840 000
398 0433 000
398 0440 000
398 0441 000
398 0442 000
398 0470 000
402 0001 000
402 0015 000
402 0107 000
STUD, BRS 1/4-20 X 1-3/4
FLAT CABLE MOUNT - BASE
FLAT CABLE MOUNT - COVER
ALLEN, 5/32 HEX, CUSHION GRIP
ADAPTER 1/4OD COMP X 1/8 MIP
RECT FW BRIDGE 600V 35A ESD
RECT 1000PIV 275A 1N4056 ESD
RECT 1000PIV 275A 1N4056R ESD
FUSE 1 TIME 6A 250VAC
FUSE 1 TIME 15A 250VAC
FUSE, ONE-TIME, 25A 250V
FUSE 1 TIME 1A 250VAC
FUSE TIME DELAY 3A 250VAC
CLIP, FUSE 1.062 60A 600V
FUSE HOLDER, 3 POLE
CLIP, FUSE 9/16
12.0
3
3
1.0
1.0
4.0
6.0
6.0
1.0
5.0
5.0
1.0
3.0
2.0
3.0
6.0
Reference Designators (B)
Table 7-4. XMTR, BASIC, DX-10 10KW - 994 9085 002 (DH)
7-4
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
Reference Designators
#FRT DOOR
#E101
#L105
#C008,#C009
RF DRIVE CABLE CLAMPS
#M001,#M002,#M003
#R008,#R009,#R010,#R011
#L001,#L002
#L001,#L002
#S009
2#T101 2#T102
#C037,#XF006
#C003,E007,E008,E009,E010,E011,E012,E013,
E048
#CR1-12,#E015,#L107 2#A26 2#E014
# USE WITH COVER 358-3301-000
# USE WITH COVER 358-3300-000
#TOOL FOR LATCHES
CR013,CR014,CR015,CR016
CR001,CR003,CR005,CR007,CR009,CR011
CR002,CR004,CR006,CR008,CR010,CR012
A24F1
A24F3,A24F8,F001,F002,F003
A24F2,A24F4,A24F5,A24F6,A24F7
F006
F007,F008,F009
#R038
XF1-3,XF4-6,XF7-9
2(#358-3660)
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
402 0189 000
410 0012 000
410 0013 000
410 0018 000
410 0023 000
410 0025 000
410 0027 000
424 0007 000
424 0023 000
424 0026 000
424 0667 000
430 0212 000
436 0289 000
448 0224 000
448 0319 000
448 0729 000
448 0871 000
448 0882 000
464 0169 000
472 1598 000
472 1604 000
476 0416 000
484 0504 000
492 0309 000
492 0743 000
494 0424 000
524 0219 000
524 0341 000
524 0342 000
524 0380 000
530 0092 000
540 1600 308
540 1600 422
CLIP, ADJ COIL 12AWG MAX
INSULATOR ROUND NS5W 0212
INSULATOR ROUND NS5W 0216
INSULATOR ROUND NS5W 0312
INSULATOR ROUND NS5W 0410
INSULATOR ROUND NS5W 0416
INSULATOR ROUND NS5W 0424
GROMMET 13/16 MTG DI
GROMMET 1 IN MTG DIA
GROMMET 3/8 MTG DIA
GROMMET, 5/8 (0.625) MTG DIA
FAN BLADE 14" DIA 30 DEG
MOTOR, 1/3HP 50/60 HZ 3PH
HANDLE ALUM
CATCH MAGNETIC
STRIKE MAGNETIC CATCH
AIR FILTER 16 X 25 X .88
* BRACKET MAGNETIC CATCH
TOOL, TRIMMER ADJUSTMENT
XFMR, RECT 829-9009-074
XFMR, PWR, 843-4038-032
CHOKE, FLTR 10MHY 12.5ADC
SNUBBER NETWK, 0.5UF, 100 OHM
INDUCTOR VAR 28UH
COIL, AIR-WOUND 125UH
CHOKE RF 8.8UH
CAP 5500 UF 200V -10, +50%
CAP 5100 UF 350WVDC -10, +50%
CAP 76000UF 40WVDC -10, +75%
CAP 120,000UF 50WVDC -10, +75%
BRACKET, CAP, 3" ID
RES 2K OHM 3W 5%
RES 75K OHM 3W 5%
1.0
2.0
2.0
6.0
3.0
8.0
2.0
4.0
1.0
3.0
2.0
1.0
1.0
6.0
2.0
2.0
2.0
2.0
1.0
1.0
1.0
1.0
2
2.0
1.0
2.0
3.0
6.0
4
2
2
6.0
9.0
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
542 0287 000
542 0293 000
542 1010 000
552 0995 000
560 0077 000
570 0292 000
570 0309 000
574 0461 000
604 0942 000
604 1079 000
604 1088 000
606 0467 000
614 0720 000
614 0774 000
620 2464 000
632 1080 000
632 1082 000
632 1133 000
638 0020 000
646 0665 000
646 1483 000
RES 10 OHM 5% 100W
RES 250 OHM 5% 100W
RES 5.5 OHM 5% 155W
RHEO 50 OHM 25 W
MOV, 275WVAC, 400J, 40MM DISC
CNTOR, 70A 24VAC 3P
CNTOR 40A 24 VAC 600V 3P
RELAY DPDT 10A 24VAC COIL
SW, AIR PRESSURE
SW DPST 15A 125/250 VAC
SWITCH, TOGGLE DPST
CKT BRKR 2A 1 POLE
*TERM BD 6 TERM
*INTERFACE, 40 PIN, TB/HDR
END TERMINAL 1-5/8"
AMMETER, 0-100A, 4.5",[W]
WATTMETER, 20KW, 4.5",[W]
AMMETER, 0-3ADC, 4.5",[W]
SHUNT, 100A 50MV +/-1%
INSPECTION LABEL
HARRIS NAMEPLATE
2.0
2.0
3.0
1.0
3.0
1.0
1.0
2.0
1.0
2.0
1.0
2.0
1.0
2.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
12/09/04
#L107
#T102
#T101
#CR016 2#R031 2#R032 2#R033 2#R019
#L107 2#R038
4#C103 4#C104 4#L103 4#L104
#E102,#E103
# RT INNER
B001
#REAR PANELS
#FRT DOOR
T002
T001
L003
C008,C009
L001,L002
L107
T101,T102
C013,C014,C015
C002,C003,C004,C005,C006,C007
C034,C035,C036,C037
C017,C018
#C036,#C037
R017,R018,R034,R035,R036,R037
R002,R003,R004,R005,R006,R007,R013,R014,R
015
R008,R009
R010,R011
R031,R032,R033
R001
RV001,RV002,RV003
K002
K001
K003,K004
S007
S001,S002
S011
CB001,CB002
TB005
TB001,TB002
J002
M002
M003
M001
SH001
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-5
646 1492 000
646 1662 009
650 0028 000
650 0135 000
813 5007 022
813 5007 026
813 5007 028
813 5007 030
813 5007 032
813 5007 033
813 5008 030
813 5009 005
813 5010 102
813 5013 030
813 5013 069
813 5021 039
813 5609 019
814 7796 002
814 7796 006
814 7917 001
817 1280 037
817 1280 038
817 1280 039
817 1280 043
817 1280 060
817 1292 002
817 1335 119
822 0922 109
822 0922 186
828 8800 001
829 8305 653
829 9009 094
829 9009 095
829 9009 096
829 9009 102
829 9009 112
829 9009 114
829 9009 116
829 9009 142
829 9009 144
829 9009 145
829 9009 149
829 9009 150
829 9009 151
829 9009 168
829 9009 169
829 9009 171
829 9009 187
829 9009 188
829 9009 193
829 9009 207
829 9009 213
829 9009 214
829 9009 217
829 9009 222
7-6
NAMEPLATE PATENT DX-10
NAMEPLATE, DX10
KNOB RD SKIRT 1.135" DIA
KNOB RD 1.772" OD SKIRT
STDOFF 6-32X1/4 1/4 DIA
STDOFF 6-32X1/2 1/4 DIA
STDOFF 6-32X3/4 1/4 DIA
STDOFF 6-32X1 1/4 DIA
STDOFF 6-32X1-1/2 1/4 DIA
STDOFF 6-32X1-3/4 1/4 DIA
STDOFF .31DIAX1.0LGX8-32
STDOFF .38 X .38RD X 6-32
STANDOFF, #10-32 X 1.37
STDOFF 10-32 X 1 1 DIA
STDOFF 1/4-20X1-1/4 1 RD
STANDOFF, 10-32 X 1/8
STUD 5/16-18 X 1-1/2 IN L
HANDLE
HANDLE, 18" X 1/2"
HOOK, 1/2IN RADIUS
SHAFT
STDOFF 1/4-20X1.75X1.00RD
STANDOFF 6-32X1.37X.25 RD
RUNNING LIST, DX-10
CAP MTG TAB
STANDOFF, FIBERGLASS
PLATE, GROUNDING
STDOFF,.25 X 5.35 X 4-40
STRAP, 1.75" X 0.50"
SPACER, CLIP
STRAP, A21C4 TERMINATION
SHAFT COUPLING
SHAFT COUPLING
ANGLE, SPARK GAP
PLATE, COIL MTG
HINGE, DOOR
INSULATOR, RECT MTG PLATE
CAP HOLDER, TOP
CLIP, METER MTG
GND STRAP, RECT HEATSINK
GND STRAP, METER SHUNT
BUSS BAR, CAP RACK
GND STRAP, CAP RACK
BRACKET, SAFETY SWITCH
TUBE, L104 TO J2
TUBE,L103 TO L105
TUBE, L103 TO L104
MOUNTING PLATE TERM BLOCK
TRIGGER, SAFETY SWITCH
BRKT, SAFETY SWITCH HVPS
PNL, LEFT FRONT ACCESS
INNER DOOR HINGE
MIDDLE RF CONDUCTOR
SWITCH PLUNGER
FRONT DOOR INSULATION
1.0
1.0
2.0
2.0
2.0
14.0
18.0
8.0
6.0
8.0
8.0
4.0
10.0
2.0
2.0
2.0
2.0
1.0
1.0
2.0
2.0
2.0
8.0
0
2.0
6.0
1.0
7.0
6.0
1.0
1.0
1.0
1.0
1.0
2.0
1.0
1.0
1.0
6.0
2.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
2.0
1.0
1.0
1.0
1.0
2.0
1.0
1.0
#L103,#L104
#T002TBSHLD
#A015,#A017,#A039 2#S001
#A028,#A035,#A036
6#A34
#A027
#A023,A025
#A24
#L001,#L002
#CR1-12
#A030
#C038,#L107
#S009
#E101
#938-4203-001
#938-4203-020
#938-4203-001 #938-4203-020
#L103,#L104
#A022
4#TB1 4#TB2
#CR1-12
#E014
#C002,#C003,#C004,#C005,#C006,#C007
#L105
#C104
#L104
#L103
E101
#L107
#CR1-12
#SH001
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
829 9009 223
829 9009 228
829 9009 229
829 9009 230
829 9009 233
829 9009 234
829 9009 235
829 9009 236
829 9009 237
829 9009 238
829 9009 239
829 9009 250
829 9009 253
839 5695 309
839 6208 078
839 6208 081
839 6208 095
839 6208 110
839 6208 233
839 6208 248
839 6208 254
839 6208 257
839 6208 258
839 6208 265
839 6208 266
839 6208 269
839 6208 282
843 4038 118
843 4038 129
843 4038 130
843 4038 138
843 4038 139
843 4038 143
843 4038 144
843 4038 145
843 4038 146
913 5007 055
914 3468 002
916 7150 002
917 2165 001
917 2244 001
SHAFT
LOWER RF COND
GROUND STRAP
TUBE, E102 TO E103
STRAP, C104 TO L105
TUBE, E102 TO L103
CROSSOVER BAR BLOCK
CROSSOVER BAR
CROSSOVER TUBE SUPPORT
BUSHING
BUSHING
ADJUSTMENT COUPLING
CTR SHELF STIFFENER
TUBE, A21L5 INTERCONNECT
RECT MTG PLATE
SHIELD, CAP HOLDER
HEATSINK, RECT
COVER, STEP-START RES.
UPPER RF CONDUCTOR
CAP MOUNTING BASE PLATE
PLATE
CROSSOVER TUBE
COIL MOUNTING CHANNEL
TOP ACCESS PANEL
SHIELD
COIL MOUNTING CHANNEL
SCHEM, OVERALL Y CONFIG
LEFT INNER DOOR FRAME
COMBINER ACCESS COVER
ACCESS COVER STIFFENER
LEAD, INDUCTOR
CROSSOVER CONDUCTOR TOP
COIL
COIL
CENTER SHIELD REAR ANGLE
LEAD, INDUCTOR
STANDOFF 6-32 X 0.45 LG
COUPLING FLEXIBLE .5 X .5
COIL CLIP
THERMAL INTERLOCK
SPACER, 1.0 LG .75 DIA
2.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
2.0
2.0
2.0
1.0
1.0
4.0
1.0
1.0
1.0
1.0
1.0
2.0
1.0
1.0
2.0
0
1.0
1.0
1.0
4.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
12.0
EA
EA
EA
EA
EA
922 1041 001
922 1042 001
922 1043 001
922 1047 001
929 8305 181
929 8305 421
929 8305 451
929 8305 649
929 9009 148
929 9009 176
929 9009 177
929 9009 178
929 9009 179
C-BRACKET
FRAME-MOTOR MTG.
HOLDING ANGLE
HONEYCOMB
BRACKET, SHORTING
COIL ASSY, 6 TURNS
PLATE, SHORTING SW.
BAR MOD
SHIELD, SAFETY XFMR
REAR SHLD
REAR SHLD
REAR SHLD
REAR SHLD
1.0
1.0
4.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
12/09/04
#FRT DOOR BTM
#FRT DOOR TOP
#L001,#L002
#L103,#L104
#C101
#L102
#L101
L102
L101
#L102
# RT FRT DOOR INTERLOCK
#C101
#L105
#E007,#E008,#E009,#E010,#E011,#E012,#E013
,#S009,#S010,E48
#B001
#S009
L105
#S009
#L105
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-7
929 9009 180
929 9009 182
929 9009 212
929 9009 218
929 9009 220
939 6208 115
939 6208 213
939 6208 267
939 6208 287
939 8187 004
939 8187 005
939 8187 006
939 8187 007
939 8187 009
939 8187 010
939 8220 295
943 3777 002
943 4038 060
943 4038 061
943 4038 067
943 4038 085
943 4038 110
943 4038 122
943 4038 123
943 4038 124
943 4038 131
943 4038 132
943 4038 136
943 4038 140
943 4038 141
943 4038 142
943 4038 152
943 5293 160
943 5293 161
943 5479 004
943 5479 005
943 5479 006
943 5479 007
943 5479 008
943 5479 010
943 5479 012
943 5479 111
952 8964 001
992 6509 002
992 6675 001
992 6730 003
992 6752 005
992 6783 001
992 6784 002
992 6786 001
992 6827 001
992 6828 001
992 6881 001
992 6916 002
992 6958 001
7-8
REAR SHLD
REAR SHLD
DOOR MOUNTING ANGLE
SWITCH, HOT ANGLE
SWITCH, GROUND ANGLE
COVER, CIRCUIT BREAKER
SHIELD, OUTPUT SAMPLE
BRACKET
SHIELD, AIR
SHIELD, LOWER LEFT BASE
PANEL, LEFT REAR
PLATE - CYLINDER
PANEL, CENTER REAR
PANEL, RIGHT REAR ACCESS
SHELF, UPPER
SHELF, CENTER
COIL, VAR. 17VC1644
CAP HOLDER, FOUR
CAP HOLDER, THREE
SHELF,CAP/XFMR
COVER, POWER SUPPLY
TOP
CENTER FRONT DOOR
DOOR REAR SKIN CENTER FRT
METER/DISPLAY PANEL
RIGHT COMBINER SUPPORT
LEFT COMBINER SUPPORT
CENTER COMPARTMENT SHELF
CROSSOVER CONDUCTOR COVER
LT CROSSOVER SHIELD
RT CROSSOVER SHIELD
REAR COMBINER COVER
GROUND STRAP
GROUND STRAP
PANEL, LEFT INNER
PANEL, OUTER RIGHT
PANEL, RIGHT INNER
PANEL, LEFT OUTER
RIGHT INNER DOOR FRAME
DOOR, RIGHT FRONT
DOOR, CENTER INNER
PLATE, CAPACITOR MTG
CABINET ASSY, WELDED
MODULATION ENCODER
PWA, FUSE
ESD SAFE
*PWA, ANALOG TO DIGITAL CONV
PWA, MULTIMETER/PROBE,ESD SAFE
DC REGULATOR
*PWA, DX SWITCH,
PWA, OUTPUT SAMPLE
PWA, EXTERNAL INTERFACE
LED BOARD
CONTROLLER
PWA, PWR DISTRIBUTION,ESD SAFE
PWA, SPLITTER, RF, ESD SAFE
1.0
1.0
1.0
1.0
1.0
1.0
1.0
2.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
2.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
#CB001
L103,L104
#C101
A036
A024
A034
A023
A030
A031
A026
A028
A032
A038
A039
A015
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
992 6967 001
RF MODULE
52.0 EA
992 6969 001
992 6970 001
992 6971 001
992 6972 001
992 6973 001
992 7002 003
992 8069 002
992 8077 002
992 8684 004
992 9298 001
BUFFER AMPLIFIER
COMB/MOTHERBD DRIVER, ESD SAFE
COMB/MOTHERBD BINARY, ESD SAFE
PWA, COMB/MOTHERBD, ESD SAFE
PWB, DRIVER SUPPLY REG
CABLE PKG.
OSCILLATOR
ANALOG INPUT BOARD
POWER SUPPLY DISCHARGE
OUTPUT MONITOR
1.0
1.0
1.0
2.0
1.0
1.0
1.0
1.0
1.0
1.0
EA
EA
EA
EA
EA
EA
EA
EA
EA
A040,A041,A042,A043,A044,A045,A046,A047,A
048,A049,A050,A051,A052,A053,A054,A055,A05
6,A057,A058,A059,A060,A061,A062,A063,A064,
A065,A066,A067,A068,A069,A070,A071,A072,A
073,A074,A075,A076,A077,A078,A079,A080,A08
1,A082,A083,A084,A085,A086,A087,A088,A089,
A090,A091
A016
A014
A18
A19,A20
A022
A017
A035
A027
Table 7-5. THERMAL INTERLOCK - 917 2165 001
Harris PN
252 0004 000
296 0260 000
354 0624 000
442 0108 000
610 0738 000
817 2165 001
Description
WIRE, STRD 18AWG YELLOW
TUBING, SHRINK 3/32 WHITE
TERMINAL, MALE
THERMOSTAT 185 DEG F N.C.
PLUG HOUSING
ASSY INSTR, THERMAL INTLK
QTY UM
0 FT
0 FT
2.0 EA
1.0 EA
1.0 EA
0.0 EA
Reference Designators (A)
#J001
S012
J001
Table 7-6. MODULATION ENCODER - 992 6509 002
Harris PN
250 0412 000
382 0159 000
382 0557 000
382 0580 000
382 0621 000
382 0622 000
382 0637 000
382 1010 000
Description
PATCH CORD, 18 IN
IC, 7407 ESD
IC, 74LS02 ESD
IC, 74LS32 ESD
IC, 74LS11N ESD
IC, 74LS14N
ESD
IC, 74LS30 ESD
IC, DS0026CN/MMH0026CP1 ESD
QTY UM
5.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
4.0 EA
2.0 EA
25.0 EA
382 1065 000
IC 74HCT273
9.0 EA
384 0205 000
384 0610 000
384 0611 000
384 0719 000
398 0020 000
398 0022 000
402 0129 000
404 0673 000
DIODE SILICON 1N914/4148 ESD
LED, GREEN ESD
LED, RED ESD
TRANSZORB 1N6373 5V 5W ESD
FUSE, FAST CART 3A 250V
FUSE, FAST CART 5A 250V
CLIP, 1/4 DIA FUSE
SOCKET, DIP, 8 PIN (DL)
12/09/04
ESD
5.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
4.0 EA
25.0 EA
Reference Designators (V)
U059
U055
U060 U061
U056
U051 U052 U053 U057
U063 U064
U001 U002 U003 U004 U005 U006 U007 U008
U009 U010 U011 U012 U013 U014 U015 U016
U017 U018 U019 U020 U021 U022 U023 U024
U062
U031 U032 U033 U034 U035 U036 U037 U049
U050
CR001 CR004 CR005 CR006 CR007
DS002 DS004
DS001 DS003
CR002 CR003
F002
F001
XF001 XF002
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-9
404 0674 000
SOCKET, DIP, 14 PIN (DL)
11.0 EA
404 0767 000
SOCKET, DIP, 20 PIN (DL)
15.0 EA
404 0790 000
HEATSINK, 8-PIN DIP
24.0 EA
506 0230 000
506 0235 000
516 0375 000
CAP .001UF 100VAC 5%
CAP .0033UF 100V 5%
CAP 0.01UF 50V -20/+80% Z5U
2.0 EA
2.0 EA
12.0 EA
516 0453 000
CAP .1UF 100V 20% X7R
32.0 EA
516 0792 000
516 0814 000
CAP NETWORK .1UF 10%
CAP NETWORK .0033UF 10%
2.0 EA
12.0 EA
516 0815 000
CAP NETWORK .001UF 10%
12.0 EA
522 0531 000
CAP 1UF 50V 20%
18.0 EA
522 0541 000
526 0108 000
540 1366 000
540 1375 000
CAP 220UF 50V 20%
CAP 4.7UF 35V 20%
RES NETWORK 100 OHM 2%
RES NETWORK 1000 OHM 2%
2.0 EA
1.0 EA
2.0 EA
12.0 EA
540 1386 000
540 1393 000
540 1466 000
RES NETWORK 10K OHM 2%
RES NETWORK 180/390 OHM
RES NETWORK 39 OHM 2%
8.0 EA
2.0 EA
12.0 EA
548 2051 000
548 2400 158
548 2400 201
RES ZERO OHM
RES 39.2 OHM 1/2W 1%
RES 100 OHM 1/2W 1%
1.0 EA
2.0 EA
46.0 EA
548 2400 221
548 2400 226
548 2400 234
548 2400 242
548 2400 258
548 2400 269
548 2400 301
548 2400 334
RES 162 OHM 1/2W 1%
RES 182 OHM 1/2W 1%
RES 221 OHM 1/2W 1%
RES 267 OHM 1/2W 1%
RES 392 OHM 1/2W 1%
RES 511 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
RES 2.21K OHM 1/2W 1%
1.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
7-10
XU001 XU002 XU003 XU004 XU005 XU006
XU007 XU008 XU009 XU010 XU011 XU012
XU013 XU014 XU015 XU016 XU017 XU018
XU019 XU020 XU021 XU022 XU023 XU024
XU062
XU051 XU052 XU053 XU055 XU056 XU057
XU059 XU060 XU061 XU063 XU064
XU031 XU032 XU033 XU034 XU035 XU036
XU037 XU042 XU043 XU044 XU045 XU046
XU047 XU049 XU050
#U001 #U002 #U003 #U004 #U005 #U006
#U007 #U008 #U009 #U010 #U011 #U012
#U013 #U014 #U015 #U016 #U017 #U018
#U019 #U020 #U021 #U022 #U023 #U024
C021 C022
C023 C024
C401 C402 C403 C404 C405 C406 C407 C408
C409 C410 C411 C412
C031 C032 C033 C034 C035 C036 C037 C049
C050 C051 C052 C053 C055 C056 C057 C060
C061 C062 C063 C064 C231 C233 C235 C237
C239 C241 C243 C245 C247 C249 C251 C253
C139 C140
C101 C102 C103 C104 C105 C106 C107 C108
C109 C110 C111 C112
C116 C117 C118 C119 C120 C121 C122 C123
C124 C125 C126 C127
C042 C043 C044 C045 C046 C047 C201 C203
C205 C207 C209 C211 C213 C215 C217 C219
C221 C223
C001 C002
C004
R139 R140
R116 R117 R118 R119 R120 R121 R122 R123
R124 R125 R126 R127
R132 R133 R134 R135 R136 R137 R141 R142
R010 R011
R101 R102 R103 R104 R105 R106 R107 R108
R109 R110 R111 R112
R145
R020 R030
R028 R234 R235 R236 R237 R238 R239 R240
R241 R242 R243 R244 R245 R246 R247 R248
R249 R250 R251 R252 R253 R254 R255 R256
R257 R258 R259 R260 R261 R262 R263 R264
R265 R266 R267 R268 R269 R270 R271 R272
R273 R274 R275 R276 R277 R278
R233
R033 R232
R023 R231
R171 R173
R170 R172
R015
R021 R031
R014
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
548 2400 369
548 2400 401
604 0851 000
604 0905 000
610 0870 000
610 0933 000
RES 5.11K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
SW, RKR 8PST DIP
SW, PB MOMENTARY
PLUG, NON-INS SHORTING
JUMPER, PWB TEST POINT
1.0 EA
6.0 EA
1.0 EA
1.0 EA
42.0 EA
13.0 EA
610 0979 000
HDR 10C 2ROW VERTICAL
13.0 EA
610 0984 000
610 0999 000
612 0904 000
612 1176 000
839 6208 088
917 1280 056
943 4038 030
HDR 34C 2ROW VERTICAL
HDR, 10 PIN, PC BD
JACK, PC MT GOLD PLATED
DIP STRIP, FEMALE 10 POS
SCHEM, MODULATION ENCODER
FIRMWARE, MODULATION ENCODER
PWB ASSY, MOD ENCODER
1.0 EA
2.0 EA
7.0 EA
6.0 EA
0.0 EA
1.0 EA
1.0 EA
Harris PN
384 0341 000
Description
RECTIFIER 1N5404 ESD
QTY UM
8.0 EA
384 0802 000
398 0017 000
402 0069 000
TRANSZORB, BIPOLAR 18V 5% ESD
FUSE, FAST CART 1A 250V
CLIP, FUSE BRONZE
1.0 EA
1.0 EA
16.0 EA
402 0129 000
516 0084 000
516 0419 000
540 1600 419
542 0121 000
548 2400 388
548 2400 469
548 2400 526
610 0998 000
610 0999 000
829 9009 128
839 6208 241
943 4038 034
999 2437 001
CLIP, 1/4 DIA FUSE
CAP DISC .02UF 600V
CAP .05 UF 500V
RES 56K OHM 3W 5%
RES 150 OHM 5% 20W
RES 8.06K OHM 1/2W 1%
RES 51.1K OHM 1/2W 1%
RES 182K OHM 1/2W 1%
HDR, 6 PIN, PC BD
HDR, 10 PIN, PC BD
BUS BAR, FUSE BD
SCHEM, OVERALL
PWB ASSY, FUSE BD
HARDWARE LIST
2.0 EA
1.0 EA
1.0 EA
2.0 EA
8.0 EA
3.0 EA
2.0 EA
6.0 EA
1.0 EA
1.0 EA
1.0 EA
0.0 EA
1.0 EA
1.0 EA
Harris PN
354 0309 000
Description
TERM SOLDER
QTY UM
22.0 EA
380 0189 000
380 0190 000
380 0587 000
382 0081 000
382 0159 000
XSTR, NPN 2N3904 ESD
XSTR, PNP 2N3906 ESD
XSTR, MJE210 ESD
IC, 7406 ESD
IC, 7407 ESD
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
Table 7-7. PWA, FUSE
R012
R022 R032 R042 R052 R062 R072
S001
S002
TP001 TP002 TP003 TP004 TP005 TP006
TP007 TP008 TP010 TP011 TP012 TP013
TP014
J001 J002 J003 J004 J005 J006 J007 J008
J009 J010 J011 J012 J016
J017
J018 J019
P009 P010 P011 P012 P013 P014 P015
P001 P002 P003 P004 P005 P006 P008
ESD SAFE - 992 6675 001
Reference Designators (J)
CR001 CR002 CR003 CR004 CR005 CR006
CR007 CR008
CR009
F009
#F001 #F002 #F003 #F004 #F005 #F006
#F007 #F008
#F009
C001
C002
R025 R026
R001 R002 R003 R004 R005 R006 R007 R008
R018 R021 R024
R014 R015
R016 R017 R019 R020 R022 R023
J001
J002
Table 7-8. *PWA, ANALOG TO DIGITAL CONV - 992 6730 003
12/09/04
Reference Designators (C)
TP001 TP002 TP003 TP004 TP005 TP006
TP007 TP008 TP009 TP010 TP011 TP012
TP013 TP014 TP015 TP016 TP017 TP018
TP019 TP020 TP021 TP022
Q009
Q002
Q001
U007
U005 U006
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-11
382 0359 000
382 0360 000
382 0472 000
382 0605 000
382 0648 000
382 0749 000
382 0770 000
382 0771 000
382 0774 000
382 0800 000
382 0882 000
382 0965 000
382 0990 000
382 1065 000
382 1079 000
382 1332 000
382 1414 000
382 1423 000
384 0205 000
384 0321 000
384 0431 000
384 0719 000
384 0720 000
384 0733 000
384 0817 000
386 0123 000
398 0019 000
402 0129 000
404 0509 000
404 0513 000
404 0673 000
404 0674 000
IC, 7815 ESD
IC, 7915 ESD
IC, LM318 ESD
IC 7905C
ESD
IC, LM339A ESD
IC NE5532A
ESD
IC, 74HC04 ESD
IC 74HC08 ESD
IC 74HC14
ESD
IC, 74HC161 ESD
IC, 78L05A ESD
IC, D/A CONVERTER ESD
*IC, LH0002CN ESD
IC 74HCT273
ESD
IC 74HC123
ESD
IC DAC-08
ESD
IC, AD1671 A/D CONV ESD
IC, LT1123
ESD
DIODE SILICON 1N914/4148 ESD
*DIODE 5082-2800 ESD
RECT. 1N4001 ESD
TRANSZORB 1N6373 5V 5W ESD
TRANSZORB 1N6377 15V 5W ESD
LED, BI-COLOR RED/GRN ESD
RECT, SCHOTTKY, CRSH2-3 ESD
ZENER, 1N4732A 4.7V ESD
FUSE, FAST CART 2A 250V
CLIP, 1/4 DIA FUSE
SOCKET, DIP, 28 PIN (DL)
HEAT SINK PA1-1CB
SOCKET, DIP, 8 PIN (DL)
SOCKET, DIP, 14 PIN (DL)
1.0 EA
1.0 EA
5.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
4.0 EA
2.0 EA
5.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
3.0 EA
6.0 EA
1.0 EA
4.0 EA
6.0 EA
7.0 EA
404 0675 000
404 0682 000
404 0767 000
410 0405 000
484 0334 000
484 0427 000
494 0238 000
494 0393 000
494 0394 000
494 0401 000
494 0411 000
494 0418 000
500 0759 000
500 0787 000
500 0832 000
500 0834 000
500 0837 000
500 0841 000
500 0844 000
516 0453 000
SOCKET, DIP, 16 PIN (DL)
SOCKET, DIP, 24 PIN (DL)
SOCKET, DIP, 20 PIN (DL)
INSULATOR XSTR TO220
LINE,DELAY 60+/-2.0 NSEC
LINE, DELAY 450NS FIXED
CHOKE RF 39UH
CHOKE RF 5.60UH
CHOKE 6.80UH
CHOKE RF 18.0UH
CHOKE RF 220.0UH
CHOKE RF 820.0UH
CAP, MICA, 100PF 500V 5%
CAP, MICA, 200PF 500V 5%
CAP, MICA, 360PF 500V 5%
CAP, MICA, 430PF 500V 5%
CAP, MICA, 510PF 500V 5%
CAP, 750PF 300V 5%
CAP, MICA, 1000PF 100V 5%
CAP .1UF 100V 20% X7R
4.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
44.0 EA
7-12
U002
U018
U009 U024 U026 U027 U028
U021
U020
U011
U017
U015
U012
U029
U019
U008
U010 U025
U003 U004
U013 U014
U022
U001
U016
CR006 CR013 CR014 CR015
CR016 CR018
CR001 CR004 CR005 CR008 CR009
CR003
CR002 CR007
DS001
CR011
CR010
F001 F002 F003
2-XF001 2-XF002 2-XF003
XU001
#Q001 #U002 #U018 #U021
XU009 XU011 XU024 XU026 XU027 XU028
XU005 XU006 XU007 XU012 XU015 XU017
XU020
XU013 XU014 XU022 XU029
XU008
XU003 XU004
#Q001
DL003
DL001
L009 L010
L005
L007 L008
L006
L001
L002 L003
C106
C014 C042 C050
C103
C047
C111 C112
C102
C105
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
516 0530 000
CAP .01UF 10% 100V X7R
16.0 EA
516 0556 000
516 0736 000
516 0765 000
516 0768 000
516 0777 000
516 0783 000
516 0830 000
516 0894 000
516 1001 000
522 0548 000
522 0561 000
522 0578 000
540 1600 118
540 1600 121
540 1600 122
540 1600 123
540 1600 205
540 1600 215
540 1600 221
548 2400 168
548 2400 230
548 2400 264
548 2400 268
548 2400 269
548 2400 274
548 2400 277
548 2400 279
548 2400 301
548 2400 312
548 2400 326
548 2400 330
548 2400 332
548 2400 335
548 2400 337
548 2400 347
548 2400 351
548 2400 358
548 2400 364
548 2400 373
548 2400 385
548 2400 401
548 2400 411
548 2400 425
548 2400 426
548 2400 437
548 2400 469
548 2400 501
CAP .33UF 100V 20%
CAP .001UF 10% 100V X7R
CAP 10PF 5% 100V C0G
CAP 18PF 5% 100V C0G
CAP 100PF 5% 100V C0G
CAP 330PF 5% 100V C0G
CAP 8200PF 10% 100V
CAP 1500PF 5% 100V C0G
CAP 3300PF 1% 100V C0G
CAP 10UF 50V 20%
CAP 100UF 63V 20%
CAP 1.0UF 50V 20%
RES 51 OHM 3W 5%
RES 68 OHM 3W 5%
RES 75 OHM 3W 5%
RES 82 OHM 3W 5%
RES 150 OHM 3W 5%
RES 390 OHM 3W 5%
RES 680 OHM 3W 5%
RES 49.9 OHM 1/2W 1%
RES 200 OHM 1/2W 1%
RES 453 OHM 1/2W 1%
RES 499 OHM 1/2W 1%
RES 511 OHM 1/2W 1%
RES 576 OHM 1/2W 1%
RES 619 OHM 1/2W 1%
RES 649 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
RES 1.3K OHM 1/2W 1%
RES 1.82K OHM 1/2W 1%
RES 2K OHM 1/2W 1%
RES 2.1K OHM 1/2W 1%
RES 2.26K OHM 1/2W 1%
RES 2.37K OHM 1/2W 1%
RES 3.01K OHM 1/2W 1%
RES 3.32K OHM 1/2W 1%
RES 3.92K OHM 1/2W 1%
RES 4.53K OHM 1/2W 1%
RES 5.62K OHM 1/2W 1%
RES 7.5K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
RES 12.7K OHM 1/2W 1%
RES 17.8K OHM 1/2W 1%
RES 18.2K OHM 1/2W 1%
RES 23.7K OHM 1/2W 1%
RES 51.1K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
2.0 EA
2.0 EA
5.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
3.0 EA
7.0 EA
3.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
5.0 EA
1.0 EA
3.0 EA
1.0 EA
4.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
5.0 EA
3.0 EA
2.0 EA
1.0 EA
1.0 EA
6.0 EA
2.0 EA
6.0 EA
2.0 EA
1.0 EA
2.0 EA
4.0 EA
1.0 EA
1.0 EA
12/09/04
C001 C002 C003 C005 C006 C009 C010 C012
C013 C015 C016 C017 C018 C019 C020 C021
C027 C028 C030 C031 C032 C035 C036 C037
C038 C039 C043 C045 C046 C054 C056 C059
C061 C062 C070 C077 C079 C080 C081 C082
C094 C104 C108 C109
C025 C029 C033 C051 C052 C058 C060 C063
C066 C071 C072 C073 C074 C075 C076 C091
C026 C055
C048 C049
C044 C087 C088 C089 C090
C057
C092
C093
C110
C101
C100
C022 C023 C024
C004 C007 C008 C011 C034 C053 C064
C040 C041 C065
R062 R083
R084
R086
R087
R085
R043
R026
R012
R019
R072
R079
R010 R013 R035 R036 R069
R046
R021 R024 R025
R040
R020 R038 R047 R063
R045
R048
R049
R006
R027
R001 R029 R034 R037 R074
R005 R053 R055
R003 R018
R071
R039
R011 R016 R022 R023 R050 R077
R009 R015
R032 R054 R065 R066 R067 R068
R002 R004
R008
R014 R017
R028 R030 R031 R064
R033
R061
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-13
548 2400 578
548 2400 601
550 0858 000
550 0958 000
604 1064 000
604 1093 000
610 0978 000
610 0984 000
610 0999 000
610 1053 000
610 1070 000
610 1121 000
612 1184 000
620 0515 000
620 1677 000
843 5400 431
843 5400 433
929 9009 198
999 2760 001
RES 634K OHM 1/2W 1%
RES 1MEG OHM 1/2W 1%
TRIMPOT 5K OHM 1/2W 10%
TRIMPOT 10K OHM 1/2W 10%
SWITCH, ROCKER DIP 2-SPST
SW, RKR DIP 6-SPST
HDR 10C 2ROW RT ANG
HDR 34C 2ROW VERTICAL
HDR, 10 PIN, PC BD
HEADER, 4 PIN, PC BD
HDR 6 PIN STRAIGHT
HDR 4C 2ROW STRAIGHT
SHUNT JUMPER 0.1" CENTERS
RECP, SCREW ON SMC
RECEPTACLE, PC MT, BNC
SCH, A/D CONVERTER
PWB, A/D CONVERTER
XFMR
HARDWARE LIST, ANALOG TO
Harris PN
384 0431 000
384 0612 000
516 0530 000
516 0555 000
548 2400 401
548 2400 446
548 2400 543
548 2400 547
548 2400 550
600 0606 000
604 0605 000
610 0978 000
610 0980 000
610 1210 000
632 1133 000
700 1305 000
839 6208 302
843 4038 202
999 2446 001
Description
RECT. 1N4001 ESD
DIODE 1N3070 ESD
CAP .01UF 10% 100V X7R
CAP .047UF 10% 100V X7R
RES 10K OHM 1/2W 1%
RES 29.4K OHM 1/2W 1%
RES 274K OHM 1/2W 1%
RES 301K OHM 1/2W 1%
RES 324K OHM 1/2W 1%
SW, ROTARY 2P 6 POS
SW, TGL DPDT ALT ACTION
HDR 10C 2ROW RT ANG
HDR 20C 2ROW RT ANG
JUMPER, FLEX 10C X 2" LG
AMMETER, 0-3ADC, 4.5",[W]
PROBE W/COILED LEAD, 4 FT
SCH, MULTIMETER
PWB, MULTIMETER
HARDWARE LIST
1.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
0.0 EA
1.0 EA
1.0 EA
1.0 EA
R070
R041 R042 R044
R078
R007
S002
S001
J007
J006
J001 J004
J008
JP010
JP011
USE 1 IN JP10 AND 2 IN JP11 #JP010 #JP011
J003
J002
T001
Table 7-9. PWA, MULTIMETER/PROBE,ESD SAFE - 992 6752 005
QTY UM
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
0.0 EA
1.0 EA
1.0 EA
Reference Designators (B)
CR004 CR005
CR001
C003
C001
R004
R005
R002
R003
R001
S001 S002
S003
J005
J004
FS001
M001
E001
Table 7-10. DC REGULATOR - 992 6783 001
Harris PN
380 0676 000
380 0677 000
382 1048 000
384 0205 000
384 0321 000
384 0431 000
384 0704 000
384 0719 000
7-14
Description
*XSTR, NPN 2N5629 ESD
XSTR, 2N6029 ESD
IC, UC3834N
ESD
DIODE SILICON 1N914/4148 ESD
*DIODE 5082-2800 ESD
RECT. 1N4001 ESD
TRIAC DRIVER MOC3020 ESD
TRANSZORB 1N6373 5V 5W ESD
QTY UM
1.0 EA
1.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
2.0 EA
2.0 EA
Reference Designators (V)
Q005
Q001
U001 U003
CR012
CR001 CR006
CR011
U002 U004
CR005 CR009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
384 0731 000
384 0762 000
384 0782 000
386 0427 000
398 0022 000
402 0129 000
404 0675 000
410 0382 000
410 0391 000
500 0759 000
500 0844 000
500 0912 000
506 0233 000
508 0345 000
516 0375 000
516 0419 000
516 0453 000
516 0891 000
522 0531 000
522 0554 000
526 0108 000
526 0311 000
540 1600 101
540 1600 111
540 1600 212
548 2051 000
548 2400 001
548 2400 118
548 2400 185
548 2400 226
548 2400 242
548 2400 290
548 2400 301
548 2400 312
548 2400 330
548 2400 341
548 2400 351
548 2400 401
548 2400 443
550 0858 000
550 0957 000
610 0933 000
* DIODE, SWITCHING 1N4607 ESD
TRIAC 2N6343A/2N6347A ESD
RECT, MR754 400V 6A ESD
ZENER LM-313H 1.22VDC ESD
FUSE, FAST CART 5A 250V
CLIP, 1/4 DIA FUSE
SOCKET, DIP, 16 PIN (DL)
INSULATOR #4 SCREW
INSULATOR TRANSISTOR T03
CAP, MICA, 100PF 500V 5%
CAP, MICA, 1000PF 100V 5%
CAP, MICA, 820PF 500V 5%
CAP .1UF 63V 5%
CAP .47UF 200VDC 10%
CAP 0.01UF 50V -20/+80% Z5U
CAP .05 UF 500V
CAP .1UF 100V 20% X7R
CAP 0.100UF 10% 50V
CAP 1UF 50V 20%
CAP 4.7UF 50V 20%
CAP 4.7UF 35V 20%
CAP 2.2UF 35V 10%
RES 10 OHM 3W 5%
RES 27 OHM 3W 5%
RES 300 OHM 3W 5%
RES ZERO OHM
RES 1 OHM 1/2W 1%
RES 15 OHM 1/2W 1%
RES 75 OHM 1/2W 1%
RES 182 OHM 1/2W 1%
RES 267 OHM 1/2W 1%
RES 845 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
RES 1.3K OHM 1/2W 1%
RES 2K OHM 1/2W 1%
RES 2.61K OHM 1/2W 1%
RES 3.32K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
RES 27.4K OHM 1/2W 1%
TRIMPOT 5K OHM 1/2W 10%
TRIMPOT 500 OHM 1/2W 10%
JUMPER, PWB TEST POINT
3.0 EA
4.0 EA
2.0 EA
1.0 EA
3.0 EA
6.0 EA
2.0 EA
4.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
4.0 EA
1.0 EA
3.0 EA
1.0 EA
4.0 EA
1.0 EA
1.0 EA
4.0 EA
3.0 EA
8.0 EA
2.0 EA
2.0 EA
3.0 EA
1.0 EA
1.0 EA
3.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
8.0 EA
610 0980 000
610 0999 000
612 1215 000
839 6208 089
839 6208 090
943 4038 072
999 2482 001
HDR 20C 2ROW RT ANG
HDR, 10 PIN, PC BD
JACK, PC BD
SCHEM, DC REGULATOR
HEATSINK, DC REGULATOR
PWB ASSY, DC REG
HARDWARE LIST
1.0 EA
3.0 EA
4.0 EA
0.0 EA
1.0 EA
1.0 EA
1.0 EA
12/09/04
CR002 CR003 CR010
Q002 Q003 Q004 Q006
CR004 CR008
CR007
F001 F002 F003
#F001 #F002 #F003
XU001 XU003
#Q001 #Q005
#Q001 #Q005
C002 C012
C018
C001
C011
C008 C017
C005 C014
C007 C016
C009 C010
C019 C020 C021 C022
C015
C003 C006 C013
C004
C023 C024 C025 C026
R026
R003
R011 R012 R013 R014
R001 R025 R036
R007 R008 R009 R010 R028 R029 R030 R031
R017 R034
R016 R033
R002 R015 R032
R020
R006
R018 R027 R035
R024
R004 R019 R021
R005
R037
R023
R022
R039
R038
TP001 TP002 TP003 TP004 TP005 TP006
TP007 TP008
J003
J001 J002 J004
XQ001 XQ005
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-15
Table 7-11. *PWA, DX SWITCH, - 992 6784 002
Harris PN
358 1928 000
358 3545 003
380 0189 000
380 0190 000
382 0463 000
382 0774 000
382 0781 000
382 0791 000
382 0800 000
382 0882 000
382 1043 000
382 1210 000
382 1387 000
382 1542 000
384 0725 000
384 0827 000
384 0849 000
384 0854 000
384 0858 000
384 0892 000
404 0673 000
404 0674 000
404 0675 000
Description
JUMPER 1/4 LG 1/8H
STANDOFF, PEM 3/8" H SNAP-TOP
XSTR, NPN 2N3904 ESD
XSTR, PNP 2N3906 ESD
IC, 4051/14051
ESD
IC 74HC14
ESD
IC, 74HC74
ESD
IC, 74HC138 ESD
IC, 74HC161 ESD
IC, 78L05A ESD
IC UDN2595
ESD
IC CD4538B
ESD
IC MAX637 ESD
IC, OP490
ESD
RECT 1N5818 ESD
LED LIGHT BAR, GREEN ESD
LED LIGHT BAR, GREEN ESD
DIODE ARRAY, 8 ISOLATED ESD
LED LIGHT BAR, YELLOW ESD
LED 4 SEG LIGHTBAR, GRN ESD
SOCKET, DIP, 8 PIN (DL)
SOCKET, DIP, 14 PIN (DL)
SOCKET, DIP, 16 PIN (DL)
QTY UM
1.0 EA
4.0 EA
4.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
4.0 EA
1.0 EA
5.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
6.0 EA
8.0 EA
404 0766 000
404 0829 000
SOCKET, DIP, 18 PIN (DL)
SOCKET, SIP20, STRAIGHT
1.0 EA
3.0 EA
492 0839 000
516 0453 000
IND 330 UH 10% 500MA
CAP .1UF 100V 20% X7R
1.0 EA
30.0 EA
516 0530 000
516 0792 000
516 0907 000
522 0531 000
522 0548 000
522 0569 000
540 1383 000
540 1387 000
540 1408 000
540 1440 000
540 1461 000
CAP .01UF 10% 100V X7R
CAP NETWORK .1UF 10%
CAP 0.330UF 10% 50V
CAP 1UF 50V 20%
CAP 10UF 50V 20%
CAP 100UF 50V 20%
RES NETWORK 100K OHM 2%
RES NETWORK 10K OHM 2%
RES NETWORK 2000 OHM 2%
RES NETWORK 2000 OHM 2%
RES NETWORK 100 OHM 2%
1.0 EA
2.0 EA
1.0 EA
1.0 EA
6.0 EA
1.0 EA
2.0 EA
4.0 EA
1.0 EA
1.0 EA
9.0 EA
540 1462 000
548 2400 401
548 2400 456
548 2400 477
548 2400 530
550 0949 000
550 0958 000
604 1111 000
604 1119 000
RES NETWORK 1000 OHM 2%
RES 10K OHM 1/2W 1%
RES 37.4K OHM 1/2W 1%
RES 61.9K OHM 1/2W 1%
RES 200K OHM 1/2W 1%
TRIMPOT 100K OHM 1/2W 10%
TRIMPOT 10K OHM 1/2W 10%
SW PB GRAY MOM W/O LED
SW PB RED MOM W/O LED
1.0 EA
2.0 EA
2.0 EA
1.0 EA
2.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
7-16
Reference Designators (H)
JP001
Q002 Q003 Q004 Q005
Q001
U003 U010
U007
U011
U008
U006
U012
U001
U013
U014
U002 U004 U005 U009
CR002
DS001 DS002 DS003 DS004 DS005
DS008
CR001
DS009
DS006 DS007
#U014
#U002 #U004 #U005 #U007 #U009 #U011
#CR001 #DS006 #DS007 #U003 #U006 #U008
#U010 #U013
#U001
#DS001 #DS002 #DS003 #DS004 #DS005
#DS008 #DS009
L001
C002 C004 C007 C010 C011 C012 C013 C014
C015 C016 C017 C018 C019 C020 C021 C023
C024 C027 C028 C029 C030 C034 C035 C036
C037 C038 C039 C040 C041 C042
C022
C031 C032
C025
C003
C001 C005 C006 C009 C026 C033
C008
R006 R007
R001 R005 R012 R023
R003
R002
R004 R026 R027 R028 R029 R030 R032 R033
R034
R024
R010 R016
R011 R015
R025
R009 R017
R013 R014
R008
S007 S008
S006
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
604 1121 000
604 1152 000
610 0933 000
SW PB BLUE MOM W/O LED
SW PB GRN MOM W/O LED
JUMPER, PWB TEST POINT
2.0 EA
3.0 EA
8.0 EA
610 0991 000
610 1043 000
610 1210 000
839 6208 301
843 4038 201
HDR, STR, 6 PIN, 0.025 SQ
HDR 40C 2ROW VERTICAL
JUMPER, FLEX 10C X 2" LG
SCH, SWITCH/METER
PWB, SWITCH/METER
1.0 EA
1.0 EA
3.0 EA
0.0 EA
1.0 EA
Harris PN
500 0841 000
500 0852 000
516 0413 000
540 1600 120
540 1600 203
610 0980 000
829 9009 231
829 9009 232
839 7953 001
843 4038 071
929 9009 203
999 2445 001
Description
CAP, 750PF 300V 5%
CAP, MICA, 1000PF 500V 5%
CAP, RF, 10PF 7.5KV 10% NPO
RES 62 OHM 3W 5%
RES 120 OHM 3W 5%
HDR 20C 2ROW RT ANG
STRAP, INTERCONNECT
STRAP, INTERCONNECT
SCHEM, OUTPUT SAMPLE
PWB, OUTPUT SAMPLE
XFMR
HARDWARE LIST
Harris PN
380 0678 000
Description
*XSTR, ARRAY QUAD 2222 ESD
QTY UM
9.0 EA
382 0359 000
382 0360 000
382 0510 000
382 0749 000
384 0720 000
IC, 7815 ESD
IC, 7915 ESD
* IC, ILQ-74 OPTO ISOL ESD
IC NE5532A
ESD
TRANSZORB 1N6377 15V 5W ESD
1.0 EA
1.0 EA
3.0 EA
4.0 EA
22.0 EA
384 0743 000
386 0082 000
404 0673 000
404 0674 000
DIODE ARRAY DUAL 8 ESD
ZENER, 1N4744A 15V 1W 5% ESD
SOCKET, DIP, 8 PIN (DL)
SOCKET, DIP, 14 PIN (DL)
5.0 EA
2.0 EA
4.0 EA
14.0 EA
404 0675 000
404 0733 000
516 0375 000
516 0453 000
SOCKET, DIP, 16 PIN (DL)
HEAT SINK
CAP 0.01UF 50V -20/+80% Z5U
CAP .1UF 100V 20% X7R
3.0 EA
2.0 EA
2.0 EA
32.0 EA
516 0511 000
516 0516 000
CAP 0.47UF 100V 20%
CAP 1UF 100V 20%
2.0 EA
2.0 EA
S004 S005
S001 S002 S003
TP001 TP002 TP003 TP004 TP005 TP006
TP007 TP008
J002
J001
FS001 FS002 FS003
Table 7-12. PWA, OUTPUT SAMPLE - 992 6786 001
QTY UM
2.0 EA
2.0 EA
4.0 EA
2.0 EA
4.0 EA
1.0 EA
1.0 EA
1.0 EA
0.0 EA
1.0 EA
2.0 EA
1.0 EA
Reference Designators (M)
C006 C008
C002 C004
C001 C003 C005 C007
R001 R002
R003 R004 R005 R006
J001
#C001 #C003 #C005 #C007
#C005
T001 T002
Table 7-13. PWA, EXTERNAL INTERFACE - 992 6827 001
12/09/04
Reference Designators (P)
Q001 Q002 Q003 Q004 Q005 Q006 Q007
Q008 Q009
U008
U009
U001 U002 U003
U004 U005 U006 U007
CR008 CR009 CR010 CR011 CR012 CR013
CR014 CR015 CR016 CR017 CR018 CR019
CR020 CR021 CR022 CR023 CR024 CR025
CR026 CR027 CR028 CR029
CR001 CR002 CR003 CR004 CR005
CR006 CR007
XU004 XU005 XU006 XU007
XCR001 XCR002 XCR003 XCR004 XCR005
XQ001 XQ002 XQ003 XQ004 XQ005 XQ006
XQ007 XQ008 XQ009
XU001 XU002 XU003
#U008 #U009
C006 C008
C007 C009 C014 C017 C018 C021 C022 C025
C026 C028 C029 C030 C031 C032 C033 C034
C035 C036 C037 C038 C039 C040 C041 C042
C043 C044 C045 C046 C047 C048 C049 C050
C011 C013
C010 C012
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-17
516 0774 000
516 0792 000
540 1375 000
540 1380 000
540 1434 000
CAP 56PF 5% 100V C0G
CAP NETWORK .1UF 10%
RES NETWORK 1000 OHM 2%
RES NETWORK 10K OHM 2%
RES NETWORK 330 OHM 2%
7.0 EA
5.0 EA
4.0 EA
2.0 EA
9.0 EA
540 1443 000
RES NETWORK 27 OHM 2%
9.0 EA
540 1446 000
540 1480 000
RES NETWORK 220K OHM 2%
RES NETWORK 180 OHM 2%
2.0 EA
18.0 EA
542 1591 000
548 2400 230
548 2400 326
548 2400 330
548 2400 343
548 2400 401
610 0780 000
610 0854 000
610 0998 000
610 0999 000
612 1131 000
614 0715 000
620 1677 000
839 6208 099
843 4038 079
999 2455 001
RES 100.0 OHM 5W 5%
RES 200 OHM 1/2W 1%
RES 1.82K OHM 1/2W 1%
RES 2K OHM 1/2W 1%
RES 2.74K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
HEADER 4C 1 ROW STRAIGHT
HEADER, 40 PIN PC RIBBON
HDR, 6 PIN, PC BD
HDR, 10 PIN, PC BD
RECEPTACLE 25 POS D
TERM BD 4 TERM
RECEPTACLE, PC MT, BNC
SCHEM, EXTERNAL INTERFACE
PWB, EXTERNAL INTERFACE
HARDWARE LIST
6.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
4.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
0.0 EA
1.0 EA
1.0 EA
Harris PN
358 2177 000
358 2827 000
Description
SPACER, LED MOUNT .380 LG
SPACER, LED MOUNT .25 LG
QTY UM
2.0 EA
26.0 EA
380 0125 000
380 0126 000
382 0309 000
382 0452 000
382 0556 000
382 0557 000
382 0558 000
382 0580 000
382 0593 000
382 0594 000
382 0648 000
382 0711 000
382 0768 000
382 0769 000
382 0770 000
382 0771 000
XSTR, NPN 2N4401 ESD
XSTR, PNP 2N4403 ESD
IC, SN74LS08N ESD
IC, LM311/CA311
ESD
IC, 74LS00N ESD
IC, 74LS02 ESD
IC, 74LS04N TTL INV ESD
IC, 74LS32 ESD
IC TL072ACP
ESD
*IC TL074ACN
ESD
IC, LM339A ESD
*PRECISION IC MULTIPLIER ESD
IC, 74HC00 ESD
IC 74HC02
ESD
IC, 74HC04 ESD
IC 74HC08 ESD
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
6.0 EA
1.0 EA
1.0 EA
3.0 EA
5.0 EA
1.0 EA
1.0 EA
1.0 EA
5.0 EA
12.0 EA
C015 C016 C019 C020 C023 C024 C027
C001 C002 C003 C004 C005
R029 R030 R038 R039
R028 R037
R001 R003 R005 R007 R009 R011 R013 R015
R017
R002 R004 R006 R008 R010 R012 R014 R016
R018
R027 R036
R048 R049 R050 R051 R052 R053 R054 R055
R056 R057 R058 R059 R060 R061 R062 R063
R064 R065
R021 R022 R023 R024 R025 R026
R019 R020
R041 R043
R045 R047
R044 R046
R040 R042
J011
J005 J006 J009 J010
J004 J012
J003
J001
TB003
J007 J008
Table 7-14. LED BOARD - 992 6828 001
7-18
Reference Designators (AR)
#DS028 #DS029
#DS001 #DS002 #DS003 #DS004 #DS005
#DS006 #DS007 #DS008 #DS009 #DS010
#DS011 #DS012 #DS013 #DS014 #DS015
#DS016 #DS018 #DS019 #DS020 #DS021
#DS022 #DS023 #DS024 #DS025 #DS026
#DS027
Q001
Q002
U040 U051
U003 U073
U017 U071
U037
U008 U009 U018 U019 U038 U053
U050
U026
U001 U002 U027
U004 U028 U044 U057 U058
U025
U020
U043
U055 U060 U061 U062 U063
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
382 0774 000
382 0777 000
382 0778 000
382 0781 000
IC 74HC14
ESD
IC, 74HC30 ESD
IC, 74HC32 ESD
IC, 74HC74
ESD
5.0 EA
1.0 EA
3.0 EA
9.0 EA
382 0853 000
382 0856 000
382 1010 000
382 1082 000
384 0205 000
IC, 74HC4050 ESD
IC 74HC4078
ESD
IC, DS0026CN/MMH0026CP1 ESD
*IC, 74HC423
ESD
DIODE SILICON 1N914/4148 ESD
4.0 EA
1.0 EA
1.0 EA
6.0 EA
9.0 EA
384 0321 000
384 0610 000
384 0611 000
384 0808 000
*DIODE 5082-2800 ESD
LED, GREEN ESD
LED, RED ESD
LED, BICOLOR, RED-GREEN ESD
5.0 EA
1.0 EA
1.0 EA
26.0 EA
404 0303 000
404 0673 000
404 0674 000
SOCKET IC 10 PIN
SOCKET, DIP, 8 PIN (DL)
SOCKET, DIP, 14 PIN (DL)
1.0 EA
4.0 EA
58.0 EA
404 0675 000
SOCKET, DIP, 16 PIN (DL)
10.0 EA
484 0351 000
494 0398 000
500 0753 000
500 0756 000
500 0844 000
506 0236 000
506 0239 000
508 0543 000
516 0054 000
516 0063 000
516 0375 000
516 0453 000
LINE DELAY 100+/-NSEC
CHOKE RF 10.0UH +/- 10%
CAP, MICA, 56PF 500V 5%
CAP, MICA, 330PF 500V 5%
CAP, MICA, 1000PF 100V 5%
CAP .0047UF 100/63V 5%
CAP .022UF 100V 5%
CAP .1UF 160V 1%
CAP, DISC .001UF 1KV 10%
CAP, DISC .002UF 1KV 20%
CAP 0.01UF 50V -20/+80% Z5U
CAP .1UF 100V 20% X7R
1.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
6.0 EA
2.0 EA
2.0 EA
2.0 EA
55.0 EA
526 0048 000
CAP 10UF 20V 20%
9.0 EA
12/09/04
U005 U013 U014 U021 U023 U029 U033 U034
U046 U047 U054 U067
U012 U022 U041 U045 U065
U066
U024 U039 U070
U006 U007 U015 U016 U035 U036 U049 U052
U064
U011 U042 U056 U059
U010
U072
U030 U031 U032 U048 U068 U069
CR001 CR002 CR003 CR006 CR007 CR008
CR009 CR011 CR015
CR004 CR005 CR010 CR013 CR014
DS028
DS029
DS001 DS002 DS003 DS004 DS005 DS006
DS007 DS008 DS009 DS010 DS011 DS012
DS013 DS014 DS015 DS016 DS018 DS019
DS020 DS021 DS022 DS023 DS024 DS025
DS026 DS027
XU025
XU003 XU026 XU072 XU073
XU001 XU002 XU004 XU005 XU006 XU007
XU008 XU009 XU010 XU012 XU013 XU014
XU015 XU016 XU017 XU018 XU019 XU020
XU021 XU022 XU023 XU024 XU027 XU028
XU029 XU033 XU034 XU035 XU036 XU037
XU038 XU039 XU040 XU041 XU043 XU044
XU045 XU046 XU047 XU049 XU050 XU051
XU052 XU053 XU054 XU055 XU057 XU058
XU060 XU061 XU062 XU063 XU064 XU065
XU066 XU067 XU070 XU071
XU011 XU030 XU031 XU032 XU042 XU048
XU056 XU059 XU068 XU069
DL001
L003
C032 C036 C038
C002
C012
C039 C040
C066
C005 C006 C007 C008 C009 C010
C068 C069
C016 C031
C001 C118
C003 C004 C011 C013 C014 C015 C017 C025
C026 C033 C034 C041 C042 C075 C076 C077
C078 C079 C080 C081 C082 C083 C084 C085
C086 C087 C088 C089 C091 C092 C093 C094
C095 C096 C097 C098 C099 C100 C101 C102
C103 C104 C105 C106 C107 C108 C109 C110
C111 C112 C113 C114 C115 C122 C123
C018 C019 C020 C021 C024 C027 C057 C058
C063
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-19
526 0050 000
526 0108 000
526 0125 000
526 0314 000
526 0321 000
526 0359 000
540 1370 000
540 1380 000
540 1391 000
540 1421 000
540 1430 000
540 1444 000
540 1457 000
540 1484 000
540 1600 203
546 0295 000
548 2400 101
548 2400 185
548 2400 218
548 2400 234
CAP 1UF 35V 20%
CAP 4.7UF 35V 20%
CAP 68UF 6V 20%
CAP 33UF 10V 20%
CAP 3.3UF 15/16V 20%
CAP 47UF 25V 10%
RES NETWORK 220 OHM 2%
RES NETWORK 10K OHM 2%
RES NETWORK 220 OHM 2%
RES NETWORK 4700 OHM 2%
RES NETWORK, 10K OHM 2%
RES NETWORK 150 OHM 2%
RES NETWORK 330 OHM 2%
RES, NETWORK 15K OHM 2%
RES 120 OHM 3W 5%
RES 50 OHM 3.25W 5%
RES 10 OHM 1/2W 1%
RES 75 OHM 1/2W 1%
RES 150 OHM 1/2W 1%
RES 221 OHM 1/2W 1%
6.0 EA
2.0 EA
1.0 EA
1.0 EA
5.0 EA
8.0 EA
5.0 EA
3.0 EA
1.0 EA
1.0 EA
2.0 EA
6.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
6.0 EA
13.0 EA
548 2400 251
RES 332 OHM 1/2W 1%
12.0 EA
548 2400 301
548 2400 330
RES 1K OHM 1/2W 1%
RES 2K OHM 1/2W 1%
5.0 EA
11.0 EA
548 2400 337
548 2400 347
548 2400 351
548 2400 354
548 2400 364
548 2400 366
548 2400 369
548 2400 377
548 2400 382
548 2400 389
548 2400 392
548 2400 401
RES 2.37K OHM 1/2W 1%
RES 3.01K OHM 1/2W 1%
RES 3.32K OHM 1/2W 1%
RES 3.57K OHM 1/2W 1%
RES 4.53K OHM 1/2W 1%
RES 4.75K OHM 1/2W 1%
RES 5.11K OHM 1/2W 1%
RES 6.19K OHM 1/2W 1%
RES 6.98K OHM 1/2W 1%
RES 8.25K OHM 1/2W 1%
RES 8.87K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
2.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
8.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
49.0 EA
548 2400 407
548 2400 413
548 2400 418
548 2400 425
548 2400 430
548 2400 437
548 2400 444
548 2400 447
548 2400 451
548 2400 455
548 2400 462
RES 11.5K OHM 1/2W 1%
RES 13.3K OHM 1/2W 1%
RES 15K OHM 1/2W 1%
RES 17.8K OHM 1/2W 1%
RES 20K OHM 1/2W 1%
RES 23.7K OHM 1/2W 1%
RES 28K OHM 1/2W 1%
RES 30.1K OHM 1/2W 1%
RES 33.2K OHM 1/2W 1%
RES 36.5K OHM 1/2W 1%
RES 43.2K OHM 1/2W 1%
1.0 EA
1.0 EA
4.0 EA
1.0 EA
4.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
2.0 EA
2.0 EA
7-20
C060 C061 C062 C064 C065 C119
C035 C067
C022
C023
C043 C044 C055 C056 C120
C045 C046 C047 C048 C049 C050 C070 C121
R121 R149 R160 R161 R162
R076 R152 R155
R190
R074
R042 R172
R043 R044 R052 R053 R110 R130
R195
R153
R081
R080
R164
R093
R061 R111 R112 R137 R138 R180
R031 R062 R094 R150 R151 R168 R169 R181
R191 R192 R193 R194 R197
R163 R196 R198 R199 R200 R201 R202 R203
R204 R205 R206 R207
R022 R064 R090 R097 R178
R002 R003 R004 R007 R026 R036 R047 R079
R082 R208 R212
R029 R030
R034 R179 R209
R001
R182
R037
R033
R066 R143 R144 R154 R157 R159 R167 R174
R005
R142
R028
R021
R027 R038 R040 R041 R046 R050 R051 R054
R055 R057 R058 R059 R060 R069 R072 R073
R077 R087 R091 R095 R096 R100 R107 R109
R115 R116 R118 R125 R126 R129 R131 R133
R135 R136 R139 R141 R145 R146 R147 R148
R165 R166 R170 R171 R173 R175 R176 R183
R186
R009
R016
R035 R039 R045 R140
R018
R008 R101 R117 R134
R156 R158
R013
R024 R067
R032
R019 R020
R010 R011
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
548 2400 469
548 2400 473
548 2400 477
548 2400 481
548 2400 487
548 2400 493
548 2400 501
548 2400 518
548 2400 530
548 2400 542
548 2400 554
548 2400 566
548 2400 581
548 2400 701
550 0858 000
550 0947 000
550 0958 000
604 0904 000
604 0905 000
610 0933 000
RES 51.1K OHM 1/2W 1%
RES 56.2K OHM 1/2W 1%
RES 61.9K OHM 1/2W 1%
RES 68.1K OHM 1/2W 1%
RES 78.7K OHM 1/2W 1%
RES 90.9K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
RES 150K OHM 1/2W 1%
RES 200K OHM 1/2W 1%
RES 267K OHM 1/2W 1%
RES 357K OHM 1/2W 1%
RES 475K OHM 1/2W 1%
RES 681K OHM 1/2W 1%
RES 10MEG OHM 1/2W 1%
TRIMPOT 5K OHM 1/2W 10%
TRIMPOT 1K OHM 1/2W 10%
TRIMPOT 10K OHM 1/2W 10%
SW, TGL SPDT
SW, PB MOMENTARY
JUMPER, PWB TEST POINT
4.0 EA
2.0 EA
1.0 EA
3.0 EA
3.0 EA
1.0 EA
6.0 EA
6.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
4.0 EA
1.0 EA
2.0 EA
17.0 EA
610 0978 000
610 0983 000
610 0986 000
610 0987 000
610 0999 000
839 6208 111
843 4038 080
929 9009 198
929 9009 257
HDR 10C 2ROW RT ANG
HDR 26C 2ROW RT ANG
HDR 40C 2ROW RT ANG
HDR 40C 2 ROW STRAIGHT
HDR, 10 PIN, PC BD
SCHEM, LED BOARD
PWB, LED BOARD
XFMR
XFMR
2.0 EA
1.0 EA
2.0 EA
1.0 EA
5.0 EA
0.0 EA
1.0 EA
1.0 EA
2.0 EA
Harris PN
335 0262 000
354 0309 000
Description
DF137A INSULATING WASHER
TERM SOLDER
QTY UM
3.0 EA
8.0 EA
358 3052 000
380 0125 000
380 0672 000
380 0673 000
380 0678 000
382 0082 000
382 0309 000
382 0594 000
382 0637 000
382 0676 000
382 0769 000
382 0770 000
382 0771 000
382 0774 000
382 0776 000
382 0778 000
382 0781 000
HOLDER, AA SIZE BATTERY
XSTR, NPN 2N4401 ESD
XSTR, D45H8 ESD
XSTR, NPN D44H8 ESD
*XSTR, ARRAY QUAD 2222 ESD
* IC 7420
IC, SN74LS08N ESD
*IC TL074ACN
ESD
IC, 74LS30 ESD
IC, 74LS05N ESD
IC 74HC02
ESD
IC, 74HC04 ESD
IC 74HC08 ESD
IC 74HC14
ESD
IC, 74HC27 ESD
IC, 74HC32 ESD
IC, 74HC74
ESD
3.0 EA
1.0 EA
2.0 EA
1.0 EA
6.0 EA
4.0 EA
2.0 EA
3.0 EA
4.0 EA
6.0 EA
1.0 EA
2.0 EA
1.0 EA
5.0 EA
1.0 EA
2.0 EA
2.0 EA
R049 R127 R128 R214
R014 R015
R213
R099 R103 R104
R006 R012 R017
R185
R063 R078 R085 R086 R089 R211
R048 R071 R105 R106 R108 R184
R083 R084
R132
R025
R210
R075
R070
R065
R068 R092
R023 R088 R098 R102
S001
S002 S003
TP001 TP002 TP003 TP004 TP005 TP006
TP007 TP008 TP009 TP010 TP011 TP013
TP014 TP015 TP016 TP017 TP018
J001 J009
J003
J007 J008
J011
J002 J004 J005 J006 J010
T001
L001 L002
Table 7-15. CONTROLLER - 992 6881 001
12/09/04
Reference Designators (AP)
#Q006 #Q008 #Q010
TP001 TP002 TP003 TP004 TP005 TP006
TP007 TP008
XBT1 XBT2 XBT3
Q013
Q006 Q008
Q010
Q001 Q002 Q003 Q004 Q005 Q012
U049 U063 U064 U065
U043 U068
U054 U055 U056
U012 U024 U036 U045
U010 U011 U022 U023 U034 U035
U073
U041 U044
U052
U051 U057 U059 U067 U074
U053
U046 U058
U070 U071
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-21
382 0791 000
382 0807 000
382 0808 000
IC, 74HC138 ESD
IC, 74HC175 ESD
IC, 74HC192
ESD
1.0 EA
1.0 EA
9.0 EA
382 0853 000
382 0974 000
382 0976 000
382 1048 000
382 1079 000
382 1080 000
382 1082 000
382 1084 000
382 1098 000
IC, 74HC4050 ESD
IC, 74LS148
ESD
IC, 14490
ESD
IC, UC3834N
ESD
IC 74HC123
ESD
IC 74HCT04 HEX INVERTER ESD
*IC, 74HC423
ESD
IC, LP339N ESD
IC 74LS126AN ESD
3.0 EA
1.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
9.0 EA
384 0205 000
384 0321 000
384 0431 000
384 0611 000
384 0719 000
384 0720 000
384 0805 000
386 0428 000
398 0015 000
398 0019 000
402 0129 000
404 0513 000
404 0674 000
DIODE SILICON 1N914/4148 ESD
*DIODE 5082-2800 ESD
RECT. 1N4001 ESD
LED, RED ESD
TRANSZORB 1N6373 5V 5W ESD
TRANSZORB 1N6377 15V 5W ESD
RECTIFIER 1N5391 ESD
DIODE LM385-1.2 1.235V 1% ESD
FUSE,FAST CART .500A 250V
FUSE, FAST CART 2A 250V
CLIP, 1/4 DIA FUSE
HEAT SINK PA1-1CB
SOCKET, DIP, 14 PIN (DL)
6.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
2.0 EA
3.0 EA
1.0 EA
2.0 EA
1.0 EA
6.0 EA
3.0 EA
50.0 EA
404 0675 000
SOCKET, DIP, 16 PIN (DL)
21.0 EA
410 0405 000
500 0759 000
506 0232 000
506 0242 000
516 0375 000
516 0453 000
INSULATOR XSTR TO220
CAP, MICA, 100PF 500V 5%
CAP .01UF 100V 5%
CAP .068UF 63V 5%
CAP 0.01UF 50V -20/+80% Z5U
CAP .1UF 100V 20% X7R
3.0 EA
3.0 EA
3.0 EA
1.0 EA
6.0 EA
52.0 EA
516 0530 000
516 0719 000
516 0774 000
516 0891 000
CAP .01UF 10% 100V X7R
CAP .0047UF 10% 100V X7R
CAP 56PF 5% 100V C0G
CAP 0.100UF 10% 50V
1.0 EA
3.0 EA
8.0 EA
3.0 EA
7-22
U040
U042
U007 U008 U009 U019 U020 U021 U031 U032
U033
U047 U048 U069
U038
U037
U060 U061 U062
U050
U039
U072
U066
U001 U002 U003 U013 U014 U015 U025 U026
U027
CR001 CR002 CR014 CR015 CR016 CR018
CR013
CR006 CR008 CR010
DS001
CR007
CR009 CR011
CR003 CR004 CR005
CR012
F002 F003
F001
#F001 #F002 #F003
#Q006 #Q008 #Q010
XU001 XU002 XU003 XU010 XU011 XU012
XU013 XU014 XU015 XU022 XU023 XU024
XU025 XU026 XU027 XU034 XU035 XU036
XU039 XU041 XU043 XU044 XU045 XU046
XU049 XU051 XU052 XU053 XU054 XU055
XU056 XU057 XU058 XU059 XU063 XU064
XU065 XU066 XU067 XU068 XU070 XU071
XU073 XU074 XQ001 XQ002 XQ003 XQ004
XQ005 XQ012
XU007 XU008 XU009 XU019 XU020 XU021
XU031 XU032 XU033 XU037 XU038 XU040
XU042 XU047 XU048 XU050 XU060 XU061
XU062 XU069 XU072
#Q006 #Q008 #Q010
C076 C083 C089
C086 C092 C129
C080
C078 C084 C090 C110 C119 C121
C001 C002 C003 C007 C008 C009 C010 C011
C012 C013 C014 C015 C019 C020 C021 C025
C026 C027 C031 C032 C033 C037 C038 C039
C040 C041 C042 C043 C044 C046 C047 C049
C050 C052 C053 C054 C055 C056 C057 C059
C060 C061 C062 C063 C064 C065 C066 C067
C068 C069 C122 C135
C093
C123 C124 C125
C111 C112 C113 C114 C115 C116 C117 C118
C137 C139 C141
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
522 0554 000
526 0048 000
CAP 4.7UF 50V 20%
CAP 10UF 20V 20%
6.0 EA
9.0 EA
526 0050 000
526 0108 000
526 0311 000
526 0314 000
526 0321 000
526 0333 000
526 0359 000
526 0374 000
540 1356 000
540 1377 000
540 1380 000
540 1434 000
540 1600 108
540 1600 211
540 1600 215
548 2051 000
548 2400 169
548 2400 201
548 2400 215
548 2400 230
548 2400 234
548 2400 293
548 2400 301
548 2400 307
548 2400 330
548 2400 347
548 2400 350
548 2400 354
548 2400 366
548 2400 369
548 2400 377
548 2400 401
CAP 1UF 35V 20%
CAP 4.7UF 35V 20%
CAP 2.2UF 35V 10%
CAP 33UF 10V 20%
CAP 3.3UF 15/16V 20%
CAP 15UF 20V 20%
CAP 47UF 25V 10%
CAP 1.0F 5.5V
RES NETWORK 10K OHM 2%
RES NETWORK 3300 OHM 2%
RES NETWORK 10K OHM 2%
RES NETWORK 330 OHM 2%
RES 20 OHM 3W 5%
RES 270 OHM 3W 5%
RES 390 OHM 3W 5%
RES ZERO OHM
RES 51.1 OHM 1/2W 1%
RES 100 OHM 1/2W 1%
RES 140 OHM 1/2W 1%
RES 200 OHM 1/2W 1%
RES 221 OHM 1/2W 1%
RES 909 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
RES 1.15K OHM 1/2W 1%
RES 2K OHM 1/2W 1%
RES 3.01K OHM 1/2W 1%
RES 3.24K OHM 1/2W 1%
RES 3.57K OHM 1/2W 1%
RES 4.75K OHM 1/2W 1%
RES 5.11K OHM 1/2W 1%
RES 6.19K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
2.0 EA
2.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
7.0 EA
2.0 EA
1.0 EA
3.0 EA
2.0 EA
4.0 EA
1.0 EA
4.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
4.0 EA
1.0 EA
5.0 EA
4.0 EA
1.0 EA
1.0 EA
1.0 EA
4.0 EA
3.0 EA
21.0 EA
548 2400 418
548 2400 446
548 2400 447
548 2400 469
548 2400 477
548 2400 481
548 2400 489
548 2400 501
548 2400 509
548 2400 530
548 2400 547
548 2400 562
548 2400 566
548 2400 585
548 2400 601
548 2400 612
604 0866 000
604 1089 000
RES 15K OHM 1/2W 1%
RES 29.4K OHM 1/2W 1%
RES 30.1K OHM 1/2W 1%
RES 51.1K OHM 1/2W 1%
RES 61.9K OHM 1/2W 1%
RES 68.1K OHM 1/2W 1%
RES 82.5K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
RES 121K OHM 1/2W 1%
RES 200K OHM 1/2W 1%
RES 301K OHM 1/2W 1%
RES 432K OHM 1/2W 1%
RES 475K OHM 1/2W 1%
RES 750K OHM 1/2W 1%
RES 1MEG OHM 1/2W 1%
RES 1.3MEG OHM 1/2W 1%
SW, PB SNAP ACTION SPDT
SW, TGL SPDT PC MOUNT
2.0 EA
2.0 EA
6.0 EA
4.0 EA
2.0 EA
1.0 EA
1.0 EA
7.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
12/09/04
C075 C079 C082 C085 C088 C091
C081 C087 C103 C105 C109 C126 C127 C131
C132
C108 C130
C101 C102
C136 C138 C140
C120
C106
C104 C077
C107
C094
R055 R056
R052
R051 R057 R058 R059 R060 R061 R062
R053 R054
R083
R082 R089 R093
R106 R107
R079 R088 R096 R111
R084
R090 R115 R127 R135
R095
R078
R112
R087 R094
R038 R039 R120 R122
R081
R021 R023 R029 R073 R124
R022 R028 R036 R041
R077
R030
R026
R016 R043 R044 R133
R031 R037 R040
R003 R004 R007 R008 R011 R012 R013 R014
R015 R024 R025 R035 R042 R046 R074 R108
R109 R114 R121 R123 R128
R032 R132
R104 R105
R034 R116 R117 R118 R119 R134
R072 R125 R126 R131
R050 R110
R071
R033
R017 R018 R045 R070 R100 R101 R113
R019 R020
R049
R102 R103
R048
R080
R129
R130
R047
S004
S005
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-23
610 0980 000
610 0986 000
610 0987 000
610 0999 000
839 6208 100
843 4038 086
HDR 20C 2ROW RT ANG
HDR 40C 2ROW RT ANG
HDR 40C 2 ROW STRAIGHT
HDR, 10 PIN, PC BD
SCHEM, CONTROLLER
PWB, CONTROLLER
1.0 EA
3.0 EA
2.0 EA
2.0 EA
0.0 EA
1.0 EA
Harris PN
522 0528 000
542 0064 000
610 1027 000
843 5400 081
843 5400 083
999 2820 002
Description
CAP 470UF 63V 20%
RES 250 OHM 5% 12W
HEADER, MALE 12 PIN
SCHEM, PWR DISTRIBUTION
PWB, POWER DISTRIBUTION
HARDWARE LIST, POWER
Harris PN
414 0310 000
610 0998 000
610 1072 000
Description
TOROID, FERRITE
HDR, 6 PIN, PC BD
HEADER 20 POS RIGHT ANGLE
QTY UM
1.0 EA
1.0 EA
12.0 EA
817 1280 041
843 4038 097
HAIR PIN, RF SPLITTER
PWB, RF SPLITTER
24.0 EA
1.0 EA
J005
J002 J007 J008
J001 J003
J004 J006
Table 7-16. PWA, PWR DISTRIBUTION,ESD SAFE - 992 6916 002
QTY UM
1.0 EA
1.0 EA
7.0 EA
0.0 EA
1.0 EA
1.0 EA
Reference Designators (B)
C001
R001
J001 J002 J003 J004 J005 J006 J007
Table 7-17. PWA, SPLITTER, RF, ESD SAFE - 992 6958 001
Reference Designators (E)
J013
J001 J002 J003 J004 J005 J006 J007 J008
J009 J010 J011 J012
Table 7-18. BUFFER AMPLIFIER - 992 6969 001
Harris PN
380 0586 000
380 0587 000
380 0665 000
382 1010 000
384 0612 000
384 0662 000
384 0802 000
386 0169 000
398 0017 000
398 0019 000
402 0129 000
404 0745 000
494 0385 000
494 0386 000
500 0888 000
506 0230 000
506 0233 000
506 0246 000
508 0378 000
516 0081 000
522 0255 000
526 0342 000
540 1600 011
540 1600 101
7-24
Description
XSTR, MJE200 ESD
XSTR, MJE210 ESD
XSTR, MOS FET MTP15N06V ESD
IC, DS0026CN/MMH0026CP1 ESD
DIODE 1N3070 ESD
LED RED ESD
TRANSZORB, BIPOLAR 18V 5% ESD
ZENER, 1N5352A 15V ESD
FUSE, FAST CART 1A 250V
FUSE, FAST CART 2A 250V
CLIP, 1/4 DIA FUSE
HEAT SINK, CLIP ON, FOR DIP IC
CHOKE RF 1.20UH
CHOKE RF 1.50UH
CAP, MICA, 3900PF 500V 5%
CAP .001UF 100VAC 5%
CAP .1UF 63V 5%
CAP 0.47UF 63V 5%
CAP .22 UF 100V 10%
CAP, DISC .01UF 1KV 20%
CAP 15 UF 50V
CAP 2.7UF 35V 10%
RES 2.7 OHM 3W 5%
RES 10 OHM 3W 5%
QTY UM
1.0 EA
1.0 EA
2.0 EA
1.0 EA
2.0 EA
3.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
6.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
4.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
Reference Designators (H)
Q001
Q002
Q003 Q004
U001
CR001 CR002
DS001 DS002 DS003
CR003 CR004
CR005
F003
F001 F002
#U001
L001
L002
C011
C001
C002
C008 C009 C018 C020
C003
C019 C021
C010
C007
R022
R005
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
540 1600 108
540 1600 201
RES 20 OHM 3W 5%
RES 100 OHM 3W 5%
4.0 EA
10.0 EA
540 1600 312
540 1600 320
542 0060 000
548 2400 101
548 2400 230
548 2400 301
839 6208 225
843 4038 101
929 9009 198
RES 3K OHM 3W 5%
RES 6.2K OHM 3W 5%
RES 100 OHM 5% 12W
RES 10 OHM 1/2W 1%
RES 200 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
SCHEM, BUFFER AMP
PWB, BUFFER AMP
XFMR
1.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
0.0 EA
1.0 EA
1.0 EA
Harris PN
000 0000 003
324 0257 000
324 0281 000
358 2837 000
358 3164 000
384 0612 000
386 0083 000
386 0123 000
500 0836 000
500 0845 000
500 0852 000
500 0887 000
500 0888 000
500 1187 000
516 0435 000
516 0453 000
540 0571 000
540 1600 123
540 1600 201
Description
FREQUENCY DETERMINED PART
NUT, CAPTIVE 6-32
NUT, CAPTIVE 4-40
STUD, PC BD 4-40 X 5/16
CARD GUIDE
DIODE 1N3070 ESD
ZENER, 1N4742A 12V ESD
ZENER, 1N4732A 4.7V ESD
CAP, MICA, 500PF 500V
CAP, MICA, 2000PF 500V 5%
CAP, MICA, 1000PF 500V 5%
CAP, MICA, 2200PF 500V 5%
CAP, MICA, 3900PF 500V 5%
CAP, MICA, 8200PF 100V 5%
CAP .05UF 100V 20%
CAP .1UF 100V 20% X7R
*RES 22 OHM 2W 10%
RES 82 OHM 3W 5%
RES 100 OHM 3W 5%
QTY UM
0.0 EA
2.0 EA
2.0 EA
1.0 EA
10.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
3.0 EA
7.0 EA
1.0 EA
1.0 EA
2.0 EA
4.0 EA
3.0 EA
13.0 EA
548 1392 000
548 2400 147
548 2400 166
548 2400 383
548 2400 401
548 2400 501
548 2400 601
604 0977 000
610 0679 000
RES .5 OHM 5W 1%
RES 30.1 OHM 1/2W 1%
RES 47.5 OHM 1/2W 1%
RES 7.15K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
RES 1MEG OHM 1/2W 1%
SW, TGL DPDT PC MOUNT
PLUG, SHORTING, .25" CTRS
1.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
19.0 EA
610 0998 000
610 1001 000
610 1005 000
610 1051 000
610 1053 000
610 1055 000
610 1063 000
612 0901 000
HDR, 6 PIN, PC BD
HDR, 10 PIN RTANG
PLUG, SHORTING .040 PINS
HOUSING 28 DUAL POSITIONS
HEADER, 4 PIN, PC BD
HOUSING 22 DUAL POSITIONS
HDR, 10 PIN PC RBN RT ANG
JACK, PC MT
2.0 EA
1.0 EA
2.0 EA
4.0 EA
4.0 EA
1.0 EA
1.0 EA
69.0 EA
R008 R009 R010 R011
R001 R002 R012 R013 R014 R015 R016 R017
R018 R019
R020
R023 R024
R021
R006 R007
R004
R003
T001
Table 7-19. COMB/MOTHERBD DRIVER, ESD SAFE - 992 6970 001
12/09/04
Reference Designators (X)
C012 C013 C014
2#J006 2#J007 2#J008 2#J009 2#J010
CR005 CR006
CR003
CR001
C016
C018
C017
C003 C004 C005
C006 C007 C008 C009 C010 C011 C019
C020
C015
C001 C002
R017 R018 R019 R020
R027 R028 R029
R006 R007 R008 R009 R010 R011 R021 R022
R023 R024 R025 R026 R030
R014
R002
R001
R013 R015
R003 R012
R004 R005
R016
S001
(2) P24 P014 P015 P017 P018 P019 P020
P021 P022 P023 P025 P026 P027 P028 P029
P030 P031 P032
J011 J012
J004
P016A P016B
J007 J008 J009 J010
J001 J002 J003 J013
J006
J005
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-25
839 6208 226
839 6208 232
839 6208 237
843 4038 099
917 1280 058
929 9009 257
992 7002 004
SCHEM, DVR COMBINER
RF COND GND SHELF
UPPER RF COND SUPPORT
DRIVER COMBINER
TAPPED COIL
XFMR
XFMR PKG (DRVR MDB)
0.0 EA
1.0 EA
1.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
999 2556 001
HARDWARE LIST
1.0 EA
Harris PN
324 0281 000
358 2837 000
358 3164 000
Description
NUT, CAPTIVE 4-40
STUD, PC BD 4-40 X 5/16
CARD GUIDE
QTY UM
4.0 EA
2.0 EA
32.0 EA
522 0628 000
540 1600 422
610 0998 000
610 1005 000
610 1051 000
CAP 220UF 400V 20%
RES 75K OHM 3W 5%
HDR, 6 PIN, PC BD
PLUG, SHORTING .040 PINS
HOUSING 28 DUAL POSITIONS
5.0 EA
5.0 EA
2.0 EA
4.0 EA
16.0 EA
610 1064 000
610 1066 000
610 1072 000
612 1012 000
817 1280 061
829 9009 248
839 6208 236
839 6208 268
843 4038 151
939 6208 270
HDR, 10 PIN PC RBN
CONN, .25 FASTON PC MOUNT
HEADER 20 POS RIGHT ANGLE
JACK PC MT .040 PINS
MOUNTING POST
COIL MOUNT
RF CONDUCTOR SUPPORT
SCH, BINARY COMBINER/MB
PWB, BINARY COMBINER MBD
COIL
5.0 EA
2.0 EA
4.0 EA
16.0 EA
4.0 EA
2.0 EA
2.0 EA
0.0 EA
1.0 EA
16.0 EA
992 7002 005
XFMR PKG (BINARY MBD)
1.0 EA
999 2515 001
HARDWARE LIST
1.0 EA
Harris PN
324 0281 000
358 2837 000
358 3164 000
Description
NUT, CAPTIVE 4-40
STUD, PC BD 4-40 X 5/16
CARD GUIDE
QTY UM
4.0 EA
2.0 EA
32.0 EA
522 0628 000
540 1600 422
610 0998 000
610 1051 000
CAP 220UF 400V 20%
RES 75K OHM 3W 5%
HDR, 6 PIN, PC BD
HOUSING 28 DUAL POSITIONS
4.0 EA
4.0 EA
2.0 EA
16.0 EA
610 1064 000
610 1072 000
HDR, 10 PIN PC RBN
HEADER 20 POS RIGHT ANGLE
4.0 EA
3.0 EA
L001 L002 L003
T012
T001 T002 T003 T004 T005 T006 T007 T008
T009 T010 T011
Table 7-20. COMB/MOTHERBD BINARY, ESD SAFE - 992 6971 001
Reference Designators (V)
2#J001 2#J002 2#J003 2#J004 2#J005 2#J006
2#J007 2#J008 2#J009 2#J010 2#J011 2#J012
2#J013 2#J014 2#J015 2#J016
C001 C002 C003 C004 C005
R001 R002 R003 R004 R005
J025 J026
P030 P031 P032 P033
J001 J002 J003 J004 J005 J006 J007 J008
J009 J010 J011 J012 J013 J014 J015 J016
J021 J022 J023 J024 J027
J028 J029
L001 L002 L003 L004 L005 L006 L007 L008
L009 L010 L011 L012 L013 L014 L015 L016
T001 T002 T003 T004 T005 T006 T007 T008
T009 T010 T011 T012 T013 T014 T015 T016
Table 7-21. PWA, COMB/MOTHERBD, ESD SAFE - 992 6972 001
7-26
Reference Designators (N)
2#J001 2#J002 2#J003 2#J004 2#J005 2#J006
2#J007 2#J008 2#J009 2#J010 2#J011 2#J012
2#J013 2#J014 2#J015 2#J016
C001 C002 C003 C004
R001 R002 R003 R004
J025 J026
J001 J002 J003 J004 J005 J006 J007 J008
J009 J010 J011 J012 J013 J014 J015 J016
J021 J022 J023 J024
J017 J019 J020
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
610 1073 000
817 1280 061
829 9009 248
839 6208 229
839 6208 236
843 4038 098
939 6208 270
HEADER 20 POS STRAIGHT
MOUNTING POST
COIL MOUNT
SCHEM, COMBINER MB. MAIN
RF CONDUCTOR SUPPORT
PWB, COMBINER/MOTHERBOARD
COIL
1.0 EA
4.0 EA
2.0 EA
0.0 EA
2.0 EA
1.0 EA
16.0 EA
992 7002 010
XFMR PKG (COMB/MOTHERBD)
1.0 EA
999 2514 001
HARDWARE LIST, COMB/MOTHERBD
1.0 EA
Harris PN
328 0071 000
380 0414 000
380 0681 000
382 0368 000
382 0593 000
384 0205 000
384 0731 000
384 0782 000
386 0085 000
386 0090 000
386 0164 000
404 0673 000
410 0413 000
494 0398 000
506 0232 000
506 0236 000
506 0245 000
516 0375 000
516 0453 000
540 1600 203
542 0005 000
546 0295 000
548 1487 000
548 2400 001
548 2400 166
548 2400 201
548 2400 293
548 2400 301
548 2400 347
548 2400 365
548 2400 401
548 2400 426
548 2400 430
548 2400 466
548 2400 485
548 2400 501
548 2400 542
548 2400 547
548 2400 566
548 2400 601
Description
WASHER, STEEL COMPRESSION
XSTR, 2N3799 ESD
XSTR IRFP350 ESD
IC, 78L15AWC VOLTAGE REG. ESD
IC TL072ACP
ESD
DIODE SILICON 1N914/4148 ESD
* DIODE, SWITCHING 1N4607 ESD
RECT, MR754 400V 6A ESD
ZENER, 1N4740A 10V ESD
ZENER 1N4756A 47V 5% 1W ESD
ZENER, 1N4754A 39V ESD
SOCKET, DIP, 8 PIN (DL)
THERMAL INTERFACE, TO-247
CHOKE RF 10.0UH +/- 10%
CAP .01UF 100V 5%
CAP .0047UF 100/63V 5%
CAP.33UF 63V 5%
CAP 0.01UF 50V -20/+80% Z5U
CAP .1UF 100V 20% X7R
RES 120 OHM 3W 5%
RES 5 OHM 5% 8W
RES 50 OHM 3.25W 5%
RES 0.1 OHM 10W 1%
RES 1 OHM 1/2W 1%
RES 47.5 OHM 1/2W 1%
RES 100 OHM 1/2W 1%
RES 909 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
RES 3.01K OHM 1/2W 1%
RES 4.64K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
RES 18.2K OHM 1/2W 1%
RES 20K OHM 1/2W 1%
RES 47.5K OHM 1/2W 1%
RES 75K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
RES 267K OHM 1/2W 1%
RES 301K OHM 1/2W 1%
RES 475K OHM 1/2W 1%
RES 1MEG OHM 1/2W 1%
J018
L001 L002 L003 L004 L005 L006 L007 L008
L009 L010 L011 L012 L013 L014 L015 L016
T1/T16 T2/T15 T3/T14 T4/T13 T5/T12 T6/T11
T7/T10 T8/T9
Table 7-22. PWB, DRIVER SUPPLY REG - 992 6973 001
12/09/04
QTY UM
5.0 EA
1.0 EA
5.0 EA
1.0 EA
1.0 EA
2.0 EA
4.0 EA
2.0 EA
4.0 EA
2.0 EA
1.0 EA
1.0 EA
5.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
3.0 EA
6.0 EA
1.0 EA
4.0 EA
1.0 EA
1.0 EA
8.0 EA
1.0 EA
6.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
4.0 EA
2.0 EA
1.0 EA
2.0 EA
13.0 EA
Reference Designators (W)
#Q002 #Q003 #Q004 #Q005 #Q006
Q001
Q002 Q003 Q004 Q005 Q006
U001
U002
CR005 CR006
CR001 CR002 CR003 CR004
CR013 CR015
CR008 CR011 CR012 CR014
CR009 CR010
CR007
XU002
#Q002 #Q003 #Q004 #Q005 #Q006
L001
C005 C013
C004
C001
C002 C006 C007
C003 C008 C009 C010 C011 C012
R005
R058 R059 R060 R061
R006
R043
R028 R029 R030 R031 R037 R038 R039 R040
R021
R023 R026 R027 R032 R035 R036
R003
R016
R001
R044 R045
R020 R022 R033
R013
R009
R014
R011
R008 R010 R025 R034
R041 R042
R004
R019 R024
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-27
550 0858 000
550 0958 000
604 1066 000
610 0980 000
610 1001 000
620 0515 000
813 5007 022
839 6208 227
839 6208 228
843 4038 102
929 9009 198
999 2480 001
TRIMPOT 5K OHM 1/2W 10%
TRIMPOT 10K OHM 1/2W 10%
SW, PC MT SLIDE SPDT
HDR 20C 2ROW RT ANG
HDR, 10 PIN RTANG
RECP, SCREW ON SMC
STDOFF 6-32X1/4 1/4 DIA
SCHEM, DRVR SUPPLY REG
HEATSINK, DRVR SPLY REG
PWB, DRVR SUPPLY REG
XFMR
HARDWARE LIST
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
6.0 EA
0.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
Harris PN
354 0309 000
Description
TERM SOLDER
QTY UM
11.0 EA
358 2399 000
380 0083 000
382 0360 000
382 0783 000
382 1010 000
382 1077 000
384 0205 000
STUD, PC BD 4-40 X 1/2
XSTR, 2N2369 ESD
IC, 7915 ESD
IC, 74HC76 ESD
IC, DS0026CN/MMH0026CP1 ESD
IC 301 ANALOG SWITCH SPDT ESD
DIODE SILICON 1N914/4148 ESD
2.0 EA
6.0 EA
1.0 EA
2.0 EA
2.0 EA
1.0 EA
7.0 EA
384 0431 000
386 0082 000
386 0093 000
386 0135 000
386 0429 000
398 0015 000
402 0129 000
404 0513 000
404 0673 000
404 0674 000
404 0675 000
404 0790 000
414 0087 000
492 0639 000
494 0196 000
500 0812 000
500 0822 000
500 0831 000
500 0888 000
506 0230 000
506 0232 000
506 0234 000
506 0236 000
506 0237 000
506 0246 000
516 0375 000
516 0453 000
RECT. 1N4001 ESD
ZENER, 1N4744A 15V 1W 5% ESD
ZENER, 1N4728A 3.3V ESD
ZENER, 1N4733A 5.1V ESD
ZENER 1N5346A 9.1V 5W 10% ESD
FUSE,FAST CART .500A 250V
CLIP, 1/4 DIA FUSE
HEAT SINK PA1-1CB
SOCKET, DIP, 8 PIN (DL)
SOCKET, DIP, 14 PIN (DL)
SOCKET, DIP, 16 PIN (DL)
HEATSINK, 8-PIN DIP
BEAD FERRITE SHIELD
COIL, VAR 1.44-2.94UH
CHOKE RF 100UH
CAP, MICA, 30PF 500V 5%
CAP, MICA, 75PF 500V 5%
CAP MICA 250UUF 500V
CAP, MICA, 3900PF 500V 5%
CAP .001UF 100VAC 5%
CAP .01UF 100V 5%
CAP .0022UF 100V 5%
CAP .0047UF 100/63V 5%
CAP .0068UF 100V 5%
CAP 0.47UF 63V 5%
CAP 0.01UF 50V -20/+80% Z5U
CAP .1UF 100V 20% X7R
1.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
4.0 EA
1.0 EA
3.0 EA
1.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
7.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
10.0 EA
R015 R046 R047 R048 R049 R050 R051 R052
R053 R054 R055 R056 R057
R002
R012
J004
J002 J003
J001
T001
Table 7-23. OSCILLATOR - 992 8069 002
7-28
Reference Designators (H)
E001 E002 E003 E004 TP001 TP002 TP003
TP004 TP005 TP006 TP007
#Y001 #Y002
Q001 Q002 Q003 Q004 Q005 Q006
U006
U001 U002
U003 U005
U004
CR002 CR003 CR006 CR007 CR008 CR009
CR010
CR005
CR001
CR011 CR012
CR004
CR013
F001 F002
#F001 #F002
#U006
#S001 #U003 #U005
XU004
XU001 XU002
#U003
L001 L002
L004
L003
C002 C004
C007
C005
C037
C013 C014 C017 C018 C027 C029 C030
C009 C019
C031
C032
C033
C006
C023 C024
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
516 0736 000
520 0439 000
522 0531 000
526 0342 000
526 0358 000
540 1600 111
540 1600 211
540 1600 212
546 0295 000
548 2400 158
548 2400 169
548 2400 201
548 2400 230
548 2400 242
548 2400 285
548 2400 301
CAP .001UF 10% 100V X7R
CAP, AIR VAR 2.4-24.5PF, 500V
CAP 1UF 50V 20%
CAP 2.7UF 35V 10%
CAP 22UF 35V 10%
RES 27 OHM 3W 5%
RES 270 OHM 3W 5%
RES 300 OHM 3W 5%
RES 50 OHM 3.25W 5%
RES 39.2 OHM 1/2W 1%
RES 51.1 OHM 1/2W 1%
RES 100 OHM 1/2W 1%
RES 200 OHM 1/2W 1%
RES 267 OHM 1/2W 1%
RES 750 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
1.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
5.0 EA
1.0 EA
3.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
10.0 EA
548 2400 334
548 2400 366
548 2400 373
548 2400 401
548 2400 426
548 2400 430
548 2400 458
548 2400 501
548 2400 601
558 0041 000
604 0852 000
610 0679 000
610 0777 000
610 0979 000
610 0999 000
612 0904 000
RES 2.21K OHM 1/2W 1%
RES 4.75K OHM 1/2W 1%
RES 5.62K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
RES 18.2K OHM 1/2W 1%
RES 20K OHM 1/2W 1%
RES 39.2K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
RES 1MEG OHM 1/2W 1%
OVEN, XTAL HC6/U 19VDC
SW, RKR DIP 4-SPST
PLUG, SHORTING, .25" CTRS
HDR 3C 1ROW STRAIGHT
HDR 10C 2ROW VERTICAL
HDR, 10 PIN, PC BD
JACK, PC MT GOLD PLATED
2.0 EA
2.0 EA
1.0 EA
5.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
1.0 EA
6.0 EA
1.0 EA
1.0 EA
2.0 EA
18.0 EA
612 1206 000
620 1677 000
829 9009 051
839 7930 032
843 5155 032
999 2450 002
JACK, PC MT FOR .050 PINS
RECEPTACLE, PC MT, BNC
BRACKET, OSC. HEATER
SCHEM, OSCILLATOR
PWB, OSCILLATOR
HARDWARE LIST
4.0 EA
2.0 EA
2.0 EA
0.0 EA
1.0 EA
1.0 EA
Harris PN
335 0262 000
380 0126 000
380 0481 000
380 0672 000
380 0673 000
382 0472 000
382 0711 000
382 0721 000
382 0749 000
Description
DF137A INSULATING WASHER
XSTR, PNP 2N4403 ESD
XSTR, NJFET 2N4092 ESD
XSTR, D45H8 ESD
XSTR, NPN D44H8 ESD
IC, LM318 ESD
*PRECISION IC MULTIPLIER ESD
IC, MC14504BCP
ESD
IC NE5532A
ESD
C011 C012 C015 C016 C020 C021 C026 C028
C034 C038
C039
C001 C003
C022 C025
C008 C036
C010
R039
R011 R012
R006 R007
R013 R017 R031 R037 R038
R003
R029 R040 R041
R022 R025
R036
R004
R009 R035
R005 R015 R016 R026 R027 R028 R030 R032
R042 R044
R008 R023
R010 R034
R024
R019 R021 R033 R043 R045
R002
R014
R001
R046
R018 R020
#Y001 #Y002
S001
P001 P002 P003 P004 P005 P006
J003
J007
J001 J004
3XP001 3XP002 3XP003 3XP004 3XP005
3XP006
#Y001 #Y002
J002 J005
Table 7-24. ANALOG INPUT BOARD - 992 8077 002
12/09/04
QTY UM
2.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
2.0 EA
6.0 EA
Reference Designators (F)
#Q005 #Q006
Q001 Q002
Q007 Q008
Q006
Q005
U003 U019
U010
U014 U016
U004 U005 U006 U007 U009 U012
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-29
382 0757 000
382 0774 000
382 1048 000
382 1065 000
384 0205 000
384 0321 000
384 0431 000
384 0612 000
384 0720 000
384 0799 000
386 0135 000
398 0015 000
402 0129 000
404 0303 000
404 0673 000
IC OP-27
ESD
IC 74HC14
ESD
IC, UC3834N
ESD
IC 74HCT273
ESD
DIODE SILICON 1N914/4148 ESD
*DIODE 5082-2800 ESD
RECT. 1N4001 ESD
DIODE 1N3070 ESD
TRANSZORB 1N6377 15V 5W ESD
DIODE, BIPOLAR ESD
ZENER, 1N4733A 5.1V ESD
FUSE,FAST CART .500A 250V
CLIP, 1/4 DIA FUSE
SOCKET IC 10 PIN
SOCKET, DIP, 8 PIN (DL)
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
3.0 EA
2.0 EA
1.0 EA
2.0 EA
3.0 EA
4.0 EA
2.0 EA
4.0 EA
1.0 EA
9.0 EA
404 0674 000
404 0675 000
404 0758 000
404 0766 000
404 0767 000
410 0405 000
494 0395 000
494 0415 000
494 0418 000
500 0759 000
500 1064 000
506 0232 000
506 0240 000
506 0243 000
506 0246 000
506 0262 000
508 0547 000
516 0375 000
SOCKET, DIP, 14 PIN (DL)
SOCKET, DIP, 16 PIN (DL)
HEAT SINK FOR TO-220
SOCKET, DIP, 18 PIN (DL)
SOCKET, DIP, 20 PIN (DL)
INSULATOR XSTR TO220
CHOKE 40UH 2 AMP
CHOKE RF 470.0UH
CHOKE RF 820.0UH
CAP, MICA, 100PF 500V 5%
CAP, MICA, 5100PF 500V 5%
CAP .01UF 100V 5%
CAP .033UF 100/63V 5%
CAP .15UF 63V 5%
CAP 0.47UF 63V 5%
CAP .047UF 100V 5%
CAP .01UF 160V 1%
CAP 0.01UF 50V -20/+80% Z5U
1.0 EA
4.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
6.0 EA
2.0 EA
1.0 EA
22.0 EA
516 0453 000
CAP .1UF 100V 20% X7R
30.0 EA
516 0765 000
516 0774 000
516 0775 000
CAP 10PF 5% 100V C0G
CAP 56PF 5% 100V C0G
CAP 68PF 5% 100V C0G
1.0 EA
5.0 EA
25.0 EA
516 0891 000
522 0554 000
526 0108 000
526 0109 000
526 0311 000
526 0318 000
540 1380 000
540 1440 000
540 1600 208
CAP 0.100UF 10% 50V
CAP 4.7UF 50V 20%
CAP 4.7UF 35V 20%
CAP 22UF 25V 20%
CAP 2.2UF 35V 10%
CAP 10UF 35V 20%
RES NETWORK 10K OHM 2%
RES NETWORK 2000 OHM 2%
RES 200 OHM 3W 5%
2.0 EA
4.0 EA
3.0 EA
2.0 EA
2.0 EA
3.0 EA
5.0 EA
2.0 EA
1.0 EA
7-30
U011
U013
U001 U002
U017 U018
CR009 CR010
CR003 CR021 CR022
CR017 CR019
CR020
CR016 CR018
CR001 CR002 CR007
CR006 CR011 CR012 CR015
F002 F003
XF002 XF003
XU010
XU003 XU004 XU005 XU006 XU007 XU009
XU011 XU012 XU019
XU013
XU001 XU002 XU014 XU016
#Q005 #Q006
XU008
XU017 XU018
#Q005 #Q006
L006 L007
L001 L003
L002 L004
C077 C080
C001 C002
C052
C003 C004
C076
C005 C006 C007 C008 C046 C053
C083 C117
C062
C010 C012 C016 C019 C023 C024 C028 C030
C031 C033 C035 C037 C040 C043 C049 C056
C059 C074 C082 C085 C114 C116
C009 C011 C017 C018 C022 C025 C027 C029
C032 C036 C038 C041 C044 C045 C047 C050
C057 C058 C060 C061 C063 C064 C066 C067
C068 C069 C070 C071 C087 C115
C055
C013 C014 C015 C020 C034
C021 C026 C039 C042 C065 C094 C095 C096
C097 C098 C099 C100 C101 C102 C103 C104
C105 C106 C107 C108 C109 C110 C111 C112
C113
C091 C093
C073 C078 C079 C081
C048 C054 C072
C086 C088
C090 C092
C075 C084 C089
R068 R069 R070 R071 R072
R047 R048
R066
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
540 1600 211
548 2051 000
548 2400 101
548 2400 201
548 2400 205
548 2400 215
548 2400 247
548 2400 251
548 2400 258
548 2400 269
548 2400 277
548 2400 281
548 2400 285
548 2400 288
548 2400 293
548 2400 301
548 2400 327
548 2400 330
548 2400 342
548 2400 347
548 2400 354
548 2400 368
548 2400 369
548 2400 373
548 2400 389
548 2400 401
548 2400 405
548 2400 407
548 2400 409
548 2400 418
548 2400 430
548 2400 466
548 2400 481
548 2400 501
548 2400 509
548 2400 601
550 0858 000
550 0949 000
550 0956 000
550 0961 000
550 1070 000
610 0777 000
610 0933 000
RES 270 OHM 3W 5%
RES ZERO OHM
RES 10 OHM 1/2W 1%
RES 100 OHM 1/2W 1%
RES 110 OHM 1/2W 1%
RES 140 OHM 1/2W 1%
RES 301 OHM 1/2W 1%
RES 332 OHM 1/2W 1%
RES 392 OHM 1/2W 1%
RES 511 OHM 1/2W 1%
RES 619 OHM 1/2W 1%
RES 681 OHM 1/2W 1%
RES 750 OHM 1/2W 1%
RES 806 OHM 1/2W 1%
RES 909 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
RES 1.87K OHM 1/2W 1%
RES 2K OHM 1/2W 1%
RES 2.67K OHM 1/2W 1%
RES 3.01K OHM 1/2W 1%
RES 3.57K OHM 1/2W 1%
RES 4.99K OHM 1/2W 1%
RES 5.11K OHM 1/2W 1%
RES 5.62K OHM 1/2W 1%
RES 8.25K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
RES 11K OHM 1/2W 1%
RES 11.5K OHM 1/2W 1%
RES 12.1K OHM 1/2W 1%
RES 15K OHM 1/2W 1%
RES 20K OHM 1/2W 1%
RES 47.5K OHM 1/2W 1%
RES 68.1K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
RES 121K OHM 1/2W 1%
RES 1MEG OHM 1/2W 1%
TRIMPOT 5K OHM 1/2W 10%
TRIMPOT 100K OHM 1/2W 10%
TRIMPOT 2K OHM 1/2W 10%
TRIMPOT 50K OHM 1/2W 10%
TRIMPOT 100 OHM 1/2W 10%
HDR 3C 1ROW STRAIGHT
JUMPER, PWB TEST POINT
2.0 EA
3.0 EA
1.0 EA
4.0 EA
4.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
3.0 EA
1.0 EA
6.0 EA
3.0 EA
2.0 EA
1.0 EA
1.0 EA
4.0 EA
2.0 EA
2.0 EA
3.0 EA
1.0 EA
1.0 EA
2.0 EA
3.0 EA
4.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
3.0 EA
17.0 EA
610 0986 000
610 0999 000
610 1146 000
612 0904 000
843 5400 445
843 5400 447
992 7220 111
999 2610 001
HDR 40C 2ROW RT ANG
HDR, 10 PIN, PC BD
PLUG, SHORTING, .4" CTRS
JACK, PC MT GOLD PLATED
PCB, ANALOG INPUT
SCHEM, ANALOG INPUT
PWA, AD7525KN REPLACEMENT (SX)
HARDWARE LIST
1.0 EA
2.0 EA
1.0 EA
3.0 EA
1.0 EA
0.0 EA
1.0 EA
1.0 EA
12/09/04
R055 R063
R064 R067 R085
R034
R029 R050 R051 R056
R001 R004 R008 R009
R060
R028
R002 R005
R003 R006
R075
R019
R007 R010
R016
R091
R057 R061
R024 R030 R038
R031
R032 R036 R037 R040 R065 R078
R011 R012 R089
R059 R076
R033
R044
R020 R021 R035 R062
R017 R086
R018 R090
R073 R077 R082
R046
R039
R079 R080
R026 R045 R074
R022 R023 R025 R081
R058 R083
R049
R042
R088
R013 R014
R027
R015 R84
R041
R053
R043
J001 J002 J003
TP001 TP002 TP003 TP004 TP005 TP006
TP007 TP008 TP009 TP010 TP011 TP012
TP013 TP014 TP015 TP016 TP017
J004
J005 J006
P001
XP001
U008
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-31
Table 7-25. POWER SUPPLY DISCHARGE - 992 8684 004
Harris PN
328 0071 000
380 0681 000
386 0085 000
410 0413 000
508 0539 000
516 0864 000
540 1600 001
540 1600 110
540 1600 401
614 0727 000
839 7930 518
843 5155 518
917 2150 682
999 2781 001
Description
WASHER, STEEL COMPRESSION
XSTR IRFP350 ESD
ZENER, 1N4740A 10V ESD
THERMAL INTERFACE, TO-247
CAP 2 UF 400VDC 10%
CAP DISC .02UF 1KV +/-20%
RES 1 OHM 3W 5%
RES 24 OHM 3W 5%
RES 10K OHM 3W 5%
TERM BD 8C 1ROW PC MT
SCHEM, PWR SUP DISCHARGE
PWB, PWR SUPPLY DISCHARGE
DISCHARGE HEATSINK
HARDWARE LIST, PWR SUP
QTY UM
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
2.0 EA
0.0 EA
1.0 EA
1.0 EA
1.0 EA
Harris PN
000 0000 003
335 0262 000
354 0309 000
Description
FREQUENCY DETERMINED PART
DF137A INSULATING WASHER
TERM SOLDER
QTY UM
4.0 EA
2.0 EA
10.0 EA
358 1928 000
JUMPER 1/4 LG 1/8H
12.0 EA
380 0125 000
380 0190 000
380 0672 000
380 0673 000
382 0309 000
382 0581 000
382 1048 000
382 1427 000
384 0321 000
384 0431 000
384 0612 000
XSTR, NPN 2N4401 ESD
XSTR, PNP 2N3906 ESD
XSTR, D45H8 ESD
XSTR, NPN D44H8 ESD
IC, SN74LS08N ESD
IC, 74LS123 ESD
IC, UC3834N
ESD
IC LM360N
ESD
*DIODE 5082-2800 ESD
RECT. 1N4001 ESD
DIODE 1N3070 ESD
2.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
4.0 EA
13.0 EA
384 0719 000
384 0720 000
384 0731 000
386 0135 000
386 0164 000
398 0015 000
402 0129 000
404 0513 000
404 0673 000
404 0674 000
404 0675 000
410 0405 000
492 0741 000
492 0744 000
492 0748 000
TRANSZORB 1N6373 5V 5W ESD
TRANSZORB 1N6377 15V 5W ESD
* DIODE, SWITCHING 1N4607 ESD
ZENER, 1N4733A 5.1V ESD
ZENER, 1N4754A 39V ESD
FUSE,FAST CART .500A 250V
CLIP, 1/4 DIA FUSE
HEAT SINK PA1-1CB
SOCKET, DIP, 8 PIN (DL)
SOCKET, DIP, 14 PIN (DL)
SOCKET, DIP, 16 PIN (DL)
INSULATOR XSTR TO220
COIL, ADJ RF 3.4-5.8 UH
COIL ADJ RF 7.1-12.5 UH
COIL ADJ RF 5.6-10. UH
2.0 EA
2.0 EA
5.0 EA
3.0 EA
2.0 EA
2.0 EA
4.0 EA
2.0 EA
2.0 EA
1.0 EA
3.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
Reference Designators (J)
Q001 Q004
CR004 CR009
C001 C003
C008 C014
R001 R003
R008 R014
R006 R012
TB001 TB002
Table 7-26. OUTPUT MONITOR - 992 9298 001
7-32
Reference Designators (K)
C005 C041 L003 L009
#Q001 #Q002
TP001 TP002 TP003 TP004 TP005 TP006
TP007 TP008 TP009 TP010
JP001 JP002 JP003 JP004 JP005 JP006
JP007 JP008 JP009 JP010 JP011 JP012
Q003 Q004
Q005 Q006
Q001
Q002
U005
U006
U001 U004
U002 U003
CR003 CR032
CR014 CR015 CR021 CR022
CR005 CR006 CR007 CR009 CR010 CR011
CR012 CR016 CR018 CR019 CR023 CR028
CR033
CR008 CR026
CR024 CR025
CR001 CR002 CR029 CR030 CR031
CR013 CR017 CR027
CR004 CR020
F001 F002
2/#F001 2/#F002
#Q001 #Q002
#U002 #U003
#U005
#U001 #U004 #U006
#Q001 #Q002
L007
L012
L008
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
492 0749 000
492 0750 000
494 0198 000
494 0404 000
500 0759 000
500 0818 000
500 0832 000
500 0841 000
500 0854 000
500 0878 000
500 0903 000
500 1187 000
500 1196 000
506 0230 000
506 0232 000
506 0234 000
506 0235 000
506 0236 000
506 0246 000
508 0412 000
508 0420 000
508 0536 000
516 0453 000
COIL ADJ RF .76-1.25 UH
COIL ADJ RF 1.65-2.75 UH
CHOKE RF 10MH
CHOKE RF 33.0UH
CAP, MICA, 100PF 500V 5%
CAP, MICA, 50PF 500V 5%
CAP, MICA, 360PF 500V 5%
CAP, 750PF 300V 5%
CAP, VAR, 300-1000PF 175V
CAP, MICA, 1500PF 500V 5%
CAP, MICA, 2700PF 500V 5%
CAP, MICA, 8200PF 100V 5%
CAP, MICA, 15,000PF 500V 5%
CAP .001UF 100VAC 5%
CAP .01UF 100V 5%
CAP .0022UF 100V 5%
CAP .0033UF 100V 5%
CAP .0047UF 100/63V 5%
CAP 0.47UF 63V 5%
CAP .047UF 200V 5%
CAP .22UF 100V 5%
CAP .033UF 400VDC 5%
CAP .1UF 100V 20% X7R
1.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
2.0 EA
1.0 EA
6.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
3.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
10.0 EA
516 0891 000
522 0554 000
526 0048 000
526 0068 000
526 0108 000
526 0311 000
548 2051 000
548 2400 162
548 2400 169
548 2400 201
548 2400 226
548 2400 230
548 2400 242
548 2400 247
548 2400 269
548 2400 281
548 2400 282
548 2400 301
548 2400 318
548 2400 330
548 2400 366
548 2400 401
CAP 0.100UF 10% 50V
CAP 4.7UF 50V 20%
CAP 10UF 20V 20%
CAP 100UF 25V 10%
CAP 4.7UF 35V 20%
CAP 2.2UF 35V 10%
RES ZERO OHM
RES 43.2 OHM 1/2W 1%
RES 51.1 OHM 1/2W 1%
RES 100 OHM 1/2W 1%
RES 182 OHM 1/2W 1%
RES 200 OHM 1/2W 1%
RES 267 OHM 1/2W 1%
RES 301 OHM 1/2W 1%
RES 511 OHM 1/2W 1%
RES 681 OHM 1/2W 1%
RES 698 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
RES 1.5K OHM 1/2W 1%
RES 2K OHM 1/2W 1%
RES 4.75K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
4.0 EA
1.0 EA
3.0 EA
1.0 EA
2.0 EA
4.0 EA
2.0 EA
1.0 EA
2.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
1.0 EA
2.0 EA
1.0 EA
7.0 EA
1.0 EA
4.0 EA
5.0 EA
10.0 EA
548 2400 458
548 2400 469
548 2400 485
548 2400 501
550 0958 000
552 0313 000
560 0035 000
574 0450 000
RES 39.2K OHM 1/2W 1%
RES 51.1K OHM 1/2W 1%
RES 75K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
TRIMPOT 10K OHM 1/2W 10%
RHEO 100 OHM 25 W
MOV, 130WVAC, 38J, 14MM DISC
RELAY SPDT 5VDC 3A
1.0 EA
3.0 EA
1.0 EA
2.0 EA
2.0 EA
2.0 EA
1.0 EA
2.0 EA
12/09/04
L005
L006
L001 L004
L002 L010
C007 C011
C036
C003 C042
C020
C006 C015 C016 C021 C029 C040
C028 C030
C004 C013
C012
C039
C017 C033 C043
C001 C010 C027
C044
C045
C046
C048 C049
C018
C014
C047
C009 C023 C025 C031 C032 C034 C035 C037
C038 C051
C052 C053 C054 C055
C019
C002 C008 C050
C024
C022 C026
C056 C057 C058 C059
R002 R044
R025
R013 R015
R048 R049
R004
R010
R027 R043
R009
R003
R018 R019
R006
R012 R016 R017 R021 R046 R053 R054
R045
R005 R011 R014 R047
R036 R037 R039 R041 R042
R001 R022 R026 R029 R030 R031 R032 R033
R038 R052
R028
R034 R035 R040
R051
R020 R050
R023 R024
R007 R008
RV001
K001 K002
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-33
604 0852 000
604 0905 000
604 0977 000
604 1064 000
604 1070 000
604 1093 000
610 0679 000
610 0980 000
610 0983 000
610 0998 000
610 0999 000
612 0904 000
620 1677 000
650 0028 000
843 5400 101
843 5400 103
929 9009 216
929 9009 257
939 6208 260
999 2496 001
SW, RKR DIP 4-SPST
SW, PB MOMENTARY
SW, TGL DPDT PC MOUNT
SWITCH, ROCKER DIP 2-SPST
SWITCH, PB MOM 3P
SW, RKR DIP 6-SPST
PLUG, SHORTING, .25" CTRS
HDR 20C 2ROW RT ANG
HDR 26C 2ROW RT ANG
HDR, 6 PIN, PC BD
HDR, 10 PIN, PC BD
JACK, PC MT GOLD PLATED
RECEPTACLE, PC MT, BNC
KNOB RD SKIRT 1.135" DIA
SCH, OUTPUT MONITOR
PWB, OUTPUT MONITOR
XFMR
XFMR
SHIELD
HARDWARE LIST
Harris PN
492 0745 000
492 0746 000
494 0238 000
494 0402 000
500 0452 000
500 0835 000
500 0852 000
500 0878 000
500 1321 000
504 0247 000
504 0248 000
504 0258 000
504 0353 000
504 0374 000
504 0377 000
504 0378 000
504 0382 000
504 0392 000
504 0418 000
504 0419 000
504 0420 000
504 0433 000
504 0436 000
504 0439 000
504 0446 000
504 0454 000
504 0461 000
504 0462 000
504 0463 000
512 0197 000
514 0240 000
Description
COIL AIR-WOUND 17UH
COIL AIR-WOUND 6.75UH
CHOKE RF 39UH
CHOKE RF 22.0UH
CAP .002UF 10% 2500V
CAP, MICA, 470PF 500V 5%
CAP, MICA, 1000PF 500V 5%
CAP, MICA, 1500PF 500V 5%
CAP. .001UF 10% 2500V
CAP 510PF 20KV 5%
CAP. MICA 750PF 20KV
CAP 1000PF 20KV 5% (293)
CAP 3000PF 12KV 5% (293)
CAP 2000PF 15KV 5% (293)
CAP 1500PF 15KV 5% (293)
CAP 1200PF 15KV 5% (293)
CAP 2400PF 12KV 5% (293)
CAP 15,000PF 4KV 5%
CAP 2700 PF 12KV 5% (293)
CAP 3300 PF 12KV 5% (293)
CAP 3900 PF 12KV 5% (293)
CAP 3600PF 12KV 5% (293)
CAP 6000PF 10KV 5%
CAP 9100PF 8KV 5% (293)
CAP 12,000PF 5KV 5% (293)
CAP 1600PF 15KV 5% (293)
CAP 1300PF 15KV 5% (293)
CAP 1800PF 15KV 5% (293)
CAP 2200PF 12KV 5% (293)
CAP 1000PF 30KV TEST
CAP, VAR 2300PF 15KV TEST
3.0 EA
2.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
1.0 EA
9.0 EA
3.0 EA
2.0 EA
0.0 EA
1.0 EA
3.0 EA
1.0 EA
1.0 EA
1.0 EA
S001 S006 S009
S003 S004
S008
S002
S005
S007
P001 P002 P003
J001
J002
J003
J006
#P001 #P002 #P003
J004 J005 J007
#R007 #R008
T001 T002 T003
L011
#A027
Table 7-27. XMTR, DX-10 10KW SS MW - 994 9085 003
7-34
QTY UM
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
Reference Designators (C)
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
514 0264 000
530 0007 000
813 5611 139
817 1280 046
829 9009 225
829 9009 226
829 9009 227
839 6208 241
839 6208 251
839 6208 252
839 6208 255
839 6208 256
843 4038 087
989 0042 001
992 6967 001
994 9085 002
CAP, VAR 1500PF 30KV TEST
FLG MTG TERM FM2D
STUD SPEC
FREQUENCY COMP CHART CCIR
STANDOFF, CAP CONTACT PLT
SHAFT, VAR CAP ADJ
SHAFT, VAR CAP ADJ
SCHEM, OVERALL
TWO CAP CONTACT PLATE
VAC CAP CONTACT PLATE
THREE CAP CONTACT PLT
QUAD CAP CONTACT PLT
CABINET OUTLINE, DX-10
PKG CHECK LIST, DX-10
RF MODULE
XMTR, BASIC, DX-10 10KW
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
0.0 EA
1.0 EA
1.0 EA
Harris PN
354 0309 000
Description
TERM SOLDER
QTY UM
18 EA
358 2399 000
380 0083 000
STUD, PC BD 4-40 X 1/2
XSTR, 2N2369 ESD
2
8
EA
EA
380 0125 000
382 0130 000
382 0360 000
382 0581 000
382 0708 000
382 0783 000
382 1010 000
382 1077 000
384 0205 000
XSTR, NPN 2N4401 ESD
IC, MCT2/IL74 ESD
IC, 7915 ESD
IC, 74LS123 ESD
IC, 74LS86 ESD
IC, 74HC76 ESD
IC, DS0026CN/MMH0026CP1 ESD
IC 301 ANALOG SWITCH SPDT ESD
DIODE SILICON 1N914/4148 ESD
2
1
1
1
1
2
3
2
9
EA
EA
EA
EA
EA
EA
EA
EA
EA
384 0431 000
384 0679 000
384 0720 000
386 0082 000
386 0093 000
386 0135 000
386 0429 000
398 0015 000
402 0129 000
404 0513 000
404 0599 000
404 0673 000
404 0674 000
404 0675 000
404 0790 000
414 0087 000
492 0639 000
494 0196 000
RECT. 1N4001 ESD
*LED, YELLOW T1-3/4
ESD
TRANSZORB 1N6377 15V 5W ESD
ZENER, 1N4744A 15V 1W 5% ESD
ZENER, 1N4728A 3.3V ESD
ZENER, 1N4733A 5.1V ESD
ZENER 1N5346A 9.1V 5W 10% ESD
FUSE,FAST CART .500A 250V
CLIP, 1/4 DIA FUSE
HEAT SINK PA1-1CB
SOCKET, DIP, 6 PIN (DL)
SOCKET, DIP, 8 PIN (DL)
SOCKET, DIP, 14 PIN (DL)
SOCKET, DIP, 16 PIN (DL)
HEATSINK, 8-PIN DIP
BEAD FERRITE SHIELD
COIL, VAR 1.44-2.94UH
CHOKE RF 100UH
1
1
1
1
2
1
1
2
4
1
1
3
3
3
1
2
1
1
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
SPARE
Table 7-28. PWA, OSCILLATOR - 992 8069 004 (B)
12/09/04
Reference Designators
E001,E002,E003,E004,TP001,TP002,TP003,TP0
04,TP005,TP006,TP007,TP0
08,TP009,TP0010,TP0011,TP0012,TP0013,TP0
014
#Y001,#Y002
Q001,Q002,Q003,Q004,Q005,Q006,Q007,Q010
Q008,Q009
U010
U006
U007
U009
U001,U002
U003,U005,U11
U004,U008
CR002,CR003,CR006,CR007,CR008,CR009,CR
010,CR014,CR015
CR005
DS1
CR018
CR001
CR011,CR012
CR004
CR013
F001,F002
#F001,#F002
#U006
XU010
#S001,#U003,#U005
XU004,XU008,XU009
XU001,XU002,XU007
#U003
L001,L002
L004
L003
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-35
500 0756 000
500 0761 000
500 0812 000
500 0837 000
500 0838 000
500 0841 000
500 0888 000
500 0912 000
506 0230 000
CAP, MICA, 330PF 500V 5%
CAP, MICA, 150PF 500V 5%
CAP, MICA, 30PF 500V 5%
CAP, MICA, 510PF 500V 5%
CAP, MICA, 560PF 300V 5%
CAP, 750PF 300V 5%
CAP, MICA, 3900PF 500V 5%
CAP, MICA, 820PF 500V 5%
CAP .001UF 100VAC 5%
1
1
2
1
1
1
1
1
9
EA
EA
EA
EA
EA
EA
EA
EA
EA
506 0232 000
506 0234 000
506 0236 000
506 0237 000
506 0246 000
516 0375 000
516 0453 000
CAP, 0.01UF 100V 5%
CAP .0022UF 100V 5%
CAP, 0.0047UF 100V 5%
CAP, 0.0068UF 100V 5%
CAP, 0.47UF 63V 5%
CAP 0.01UF 50V -20/+80% Z5U
CAP .1UF 100V 20% X7R
2
1
2
1
1
2
17
EA
EA
EA
EA
EA
EA
EA
516 0516 000
516 0725 000
516 0736 000
520 0439 000
522 0531 000
526 0342 000
526 0358 000
540 1600 111
540 1600 209
540 1600 212
546 0295 000
548 2400 126
548 2400 130
548 2400 169
548 2400 193
548 2400 201
548 2400 230
548 2400 239
548 2400 242
548 2400 285
548 2400 301
CAP 1UF 100V 20%
CAP 1.0UF 50V 20%
CAP .001UF 10% 100V X7R
CAP, AIR VAR 2.4-24.5PF, 500V
CAP 1UF 50V 20%
CAP 2.7UF 35V 10%
CAP 22UF 35V 10%
RES 27 OHM 3W 5%
RES 220 OHM 3W 5%
RES 300 OHM 3W 5%
RES 50 OHM 3.25W 5%
RES 18.2 OHM 1/2W 1%
RES 20 OHM 1/2W 1%
RES 51.1 OHM 1/2W 1%
RES 90.9 OHM 1/2W 1%
RES 100 OHM 1/2W 1%
RES 200 OHM 1/2W 1%
RES 249 OHM 1/2W 1%
RES 267 OHM 1/2W 1%
RES 750 OHM 1/2W 1%
RES 1K OHM 1/2W 1%
1
1
1
2
2
2
1
1
4
2
5
2
1
4
4
3
1
1
1
2
15
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
548 2400 326
548 2400 334
548 2400 341
548 2400 366
548 2400 368
548 2400 373
548 2400 401
RES 1.82K OHM 1/2W 1%
RES 2.21K OHM 1/2W 1%
RES 2.61K OHM 1/2W 1%
RES 4.75K OHM 1/2W 1%
RES 4.99K OHM 1/2W 1%
RES 5.62K OHM 1/2W 1%
RES 10K OHM 1/2W 1%
1
2
1
2
1
3
10
EA
EA
EA
EA
EA
EA
EA
548 2400 430
548 2400 458
548 2400 501
548 2400 601
550 0858 000
550 0961 000
RES 20K OHM 1/2W 1%
RES 39.2K OHM 1/2W 1%
RES 100K OHM 1/2W 1%
RES 1MEG OHM 1/2W 1%
TRIMPOT 5K OHM 1/2W 10%
TRIMPOT 50K OHM 1/2W 10%
1
1
4
3
1
1
EA
EA
EA
EA
EA
EA
7-36
C040
C007
C002,C004
C005
C041
C042
C037
C044
C013,C014,C017,C018,C027,C029,C030,C047,C
049
C009,C019
C031
C012,C032
C033
C006
C023,C024
C011,C015,C016,C020,C021,C026,C028,C034,C
035,C038,C043,C045,C046,C051,C052,C053,C0
54
C048
C050
C039
C001,C003
C022,C025
C008,C036
C010
R039
R011,R012,R076,R078
R006,R007
R013,R017,R031,R037,R038
R066,R067
R003
R029,R040,R041,R054
R055,R056,R057,R058
R022,R025,R051
R036
R072
R004
R009,R035
R005,R015,R016,R026,R027,R028,R030,R032,R
042,R044,R053,R059,R060,R061,R062
R049
R008,R023
R047
R010,R034
R070
R024,R050,R052
R019,R021,R033,R043,R045,R063,R071,R073,R
074,R077
R014
R001
R046,R065,R068,R069
R002,R018,R020
R048
R064
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
558 0041 000
559 0053 000
560 0121 003
604 0852 000
610 0679 000
610 0877 000
610 0900 000
610 0979 000
610 0999 000
610 1110 000
610 1455 000
612 0904 000
OVEN, XTAL HC6/U 19VDC
THERMISTOR,NTC,10K@25C,1%
POSISTOR 0.2 AMP 60VDC DISC
SW, RKR DIP 4-SPST
PLUG, SHORTING, .25" CTRS
HDR, STR, 2 PIN, SQ
HEADER 3 CKT STRAIGHT
*HDR 10C VERT 2ROW TOP LATCH
HDR, 10 PIN, PC BD
HDR 8C 2R STRT UNPOL
HDR, 3C 1ROW VERTICAL
JACK, PC MT GOLD PLATED
2
1
1
1
7
3
1
1
2
1
1
21
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
EA
612 1184 000
612 1206 000
614 0909 000
620 1677 000
829 9009 051
843 5155 851
843 5155 853
999 2450 002
SHUNT JUMPER 0.1" CENTERS
JACK, PC MT FOR .050 PINS
TERM STRIP, 3C PCB MODULAR 237
RECEPTACLE, PC MT, BNC
BRACKET, OSC. HEATER
SCH, OSCILLATOR
PWB, OSCILLATOR
HARDWARE LIST
2
4
2
2
2
0
1
1
EA
EA
EA
EA
12/09/04
#Y001,#Y002
RT001
R075
S001
P001,P002,P004,P005,P006,P007,P008
JP4,JP5,JP6
JP1
J007
J001,J004
JP2
J003
3XP001,3XP002,3XP004,3XP005,3XP006,3XP0
07,3XP008
#Y001,#Y002
J6,J8
J002,J005
EA
888-2247-006
WARNING: Disconnect primary power prior to servicing.
7-37
7-38
888-2247-006
WARNING: Disconnect primary power prior to servicing.
12/09/04
Section A
Oscillator (A17)
A.1 Introduction
This section includes a description and troubleshooting information of the -002 and -004 Oscillator boards. The two descriptions are included in this chapter, check the board number you
have against the sections in this chapter to locate the proper
descrition.
A.3.5 Duty Cycle Adjust -004 assembly only
In combined type systems this circuit is used to help NULL out
harmonics in the output spectrum.
A.4 Circuit Description, -002 assembly
A.2 Location
The Oscillator is located in the Center Control Compartment of
the transmitter, on the inner right wall.
A.3 Principles of Operation
The Oscillator provides an rf signal at the transmitter operating
frequency, and also allows for an external rf input. Refer to
SECTION V, Maintenance, for adjustment and pc board maintenance procedures.
The Oscillator board includes a crystal oscillator stage, frequency dividers, and amplifier/driver stages. It provides an RF
signal at the transmitter operating frequency to be amplified by
the Buffer Amplifier.
A.3.1 RF Flow
Two crystals, with manual switch-over, are used to generate a
sinewave RF signal that is either four or eight times the transmitter frequency. A buffer/squaring amplifier converts the sinewave into a squarewave which is then divided down to the
transmitter frequency by the Frequency Divider. Jumper plugs
and buffer/driver amplifiers allow the use of an external oscillator source, and there are also provisions for combined transmitter
operation. The Oscillator output, at the carrier frequency, is sent
to the Buffer Amplifier via the Oscillator Interface board. The
Oscillator board also has an output signal to operate a frequency
monitor or counter. RF presence signals are sent to the Oscillator
Interface board for fault sensing.
A.3.2 VSWR Switching
A VSWR-H input signal operates an analog switch when a
VSWR fault occurs. During this time, the Oscillator output will
be switched from the crystal or External oscillator output, to an
RF current sample taken from the output network.
A.3.3 Power Supplies
+22Vdc is regulated down to +15Vdc, +9Vdc, and +5Vdc for on
board circuits, while -22Vdc is regulated down to -15Vdc to
power the crystal ovens
A.3.4 AUTO Switching -004 assembly only
When the loss of the External RF signal is detected the Oscillator
board when in Auto mode will switch to the Internal Crystal.
03/16/2009
Assembly #
PWB #
Schematic #
992-8069-002
843-5155-032
839-7930-032
Refer to schematic 839-7930-032 in the Drawing Package for
the -002 Oscillator assembly. The follow paragraphs contain
information for the -002 assembly.
A.4.1 Supply Voltages and Voltage Regulators
Input voltages from the Low Voltage power supply are +22 Vdc
and -22 Vdc through F1 and F2. Voltage regulator U6 provides
-15 Vdc for the crystal oven. All positive voltages are regulated
by zener diodes, and include +15 Vdc from CR1, +9 Vdc from
CR13, and +5 Vdc from CR4.
A.4.2 Oscillator Stage
The crystal oscillator stage, Q1, is a standard Pierce circuit,
operating at four or eight times the carrier frequency. The crystal
operates in its parallel resonant mode. A jumper plug, P1, allows
selecting either one of two crystals. If one crystal should fail, this
jumper allows quick selection of the backup crystal (the oven
jumper P6 must also be changed). For each crystal, small frequency adjustments can be made with C1 (for crystal Y1) or C3
(for Y2).
For carrier frequencies of 1250 kHz and below, the crystal
frequency is eight times the carrier frequency, and for carrier
frequencies above 1250 kHz, the crystal frequency is four times
the carrier frequency.
The +15 Vdc supply voltage for the oscillator is derived from
+22 Vdc and is regulated by zener diode CR1. The oscillator
supply voltage can be measured at TP1.
Each crystal is contained in a sleeve type oven, which maintains
temperature at 70°C (+/-3°C, approximately). Oven jumper plug
P6 supplies -15 Vdc to either oven. Note that crystal jumper plug
P1 and oven jumper plug P6 must both be in either the upper
position or both be in the lower position.
A.4.3 Buffer/Squaring Amplifier
Buffer amplifier Q2 is coupled to the oscillator output, and
operates as an overdriven amplifier, with a +5 Vdc supply
voltage. The output of Q2 is a TTL-level square wave which
drives the frequency divider.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
A-1
A.4.4 Frequency Divider
Integrated circuits U1 and U2 are dual J-K flip-flops, used as
frequency dividers. Each IC section is connected as a divide-bytwo circuit. The signal at P2-2 is one-fourth the crystal frequency
and the signal at P2-3 is one-eighth the crystal frequency. Jumper
plug P2 routes the selected frequency to buffer/driver U5-2. The
output of U5-7 at TP-5 is a TTL level square wave at the
transmitter operating frequency.
If the transmitter frequency is 1250 kHz or below, P2 is jumpered
between 1 and 2. It the transmitter frequency is above 1250 Khz,
P2 is jumpered between 1 and 3.
A.4.5 External Input
Jumper plug P3 is used to select either the internal oscillator or
an external oscillator. An external input signal can be connected
to BNC jack J2.
Jumper plug P5 selects an external input impedance of 50 Ohms
or 20k Ohms. The high impedance input is for use with TTL level
(4 to 4.5 Volt peak-to-peak square wave) inputs. The 50 Ohm
input impedance is for use with rf input levels from 0 to +25
dBm. Amplifier Q3 and buffer/driver U5 provide a logic-level
signal to P3-2.
A.4.6 Normal or Combined Transmitter Operation
Jumper plug P4 is used to select either normal or combined
transmitter operation. For normal operation, P4-1 and P4-3 are
jumpered, and the rf signal from buffer/driver U5 is fed to U4-4.
For combined operation, P4-1 and P4-2 are connected. The rf
signal is then routed through R29, J4-1, and the External Interface to the combiner control unit. When transmitters are combined, the oscillator from either transmitter can be used. The
combiner control unit will provide two outputs from one oscillator; the selected rf signal is then returned to each transmitter’s
Oscillator at J4-4.
A.4.7 Frequency Monitor Output
Buffer/driver U3-5 provides an output signal for a frequency
monitor or counter. Resistor R17 sets the driver output impedance at 50 Ohms. The frequency monitor output signal, at BNC
connector J5, will be a 4-4.5 Vp-p square wave at the transmitter
operating frequency when the monitor impedance is 50 Ohms.
If the impedance is higher than 50 Ohms, the output signal level
will be higher.
A.4.8 Oscillator Sync
“Oscillator Sync” synchronizes the rf drive phase to any ringing
currents in the combiner/output network during VSWR protection. The circuit replaces the oscillator signal with a current
sample from the output network. The oscillator sync is adjusted
with DIP switch S1 and inductor L4.
The Output Current sample from T6 at the combiner output is
brought into the Oscillator at J3-1. Resistor R37 provides a
50-ohm input impedance, and zener diodes CR11 and CR12
protect Q4 from transient voltages. The signal phase is adjusted
by DIP-switch selected capacitors C30 through C33 and L4. The
A-2
signal is converted to TTL level by Q4 and fed to CMOS analog
switch U4-11.
During normal operation, the Oscillator signal is routed through
U4 to buffer-driver U3 and then to the Buffer Amplifier. During
VSWR protection a logic HIGH signal from the LED Board
turns on Q5 and switches U4 so that the output current sample
is used as the transmitter’s rf drive.
Because the air system does not operate until the Power Amplifier stage is energized, the Oscillator output to the Buffer Amplifier is muted to protect it from over-dissipation. The VSWR-H
input is held HIGH by the LED Board when the transmitter is
OFF.
A.4.9 Oscillator Output (Buffer-Driver)
The output of driver amplifier U3-7 is a square wave at the carrier
frequency. The signal is sent to the Driver Combiner Motherboard where it drives the input of Buffer Amplifier A16.
A.4.10 “RF Present” Output
• The output from U3-7 is converted to positive and negative
dc voltages by peak detectors CR7-C18 and CR6-C17.
These voltages are used for the Oscillator RF Sense circuit
on the LED Board.
A.5 Circuit Description, -004 assembly
Assembly #
PWB #
Schematic #
992-8069-004
843-5155-853
843-5155-851
Refer to schematic 843-5155-851 in the Drawing Package for
the -004 Oscillator assembly. The follow paragraphs contain
information for the -004 assembly.
The -004 oscillator board provides a auto/man switch of the Ext
rf to the Internal crystal. It provides a duty cycle adjustment.
Normally Oscillator A is selected by the Oscillator Interface. If
optional Oscillator B is installed it can also be selected for
operation.
A.5.1 Oscillator Stage
The crystal oscillator stage, Q1, is a standard Pierce circuit,
operating at 4 or 8 times the carrier frequency. The crystal
operates in its parallel resonant mode. Jumper plug, P1, allows
selecting either one of two crystals. If one crystal should fail, this
jumper allows quick selection of the backup crystal (the oven
jumper must also be changed).
For each crystal, small frequency adjustments can be made with
C1 (for crystal Y1) or C3 (for Y2).
For carrier frequencies of 1250 kHz and below, the crystal
frequency is eight times the carrier frequency, and for carrier
frequencies above 1250 kHz, the crystal operates at four times
the carrier frequency.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure A-1
Oscillator -004 assemly, Simplified Block Diagram
Each crystal is contained in a sleeve type oven, which maintains
temperature at 70°C (+/-3°C, approximately). Oven jumper plug
P6 supplies -15Vdc to either oven. Note that crystal jumper plug
P1 and oven jumper plug P6 must both be in the same position,
otherwise the crystal in use will not be at the correct temperature
and may be off frequency (P1 and P6 must both be in the upper
position, or both in the lower position).
A.5.2 Buffer/Squaring Amplifier
Buffer amplifier Q2 is coupled to the oscillator output, and
operates as an overdriven amplifier, with a +5 volt supply
voltage. The output of Q2 is a TTL-level square wave which
drives the frequency divider. Diodes CR2 and CR3 protect Q2
against reverse voltages.
A.5.3 Frequency Divider
Integrated circuits U1 and U2 are dual J-K flip-flops, used as
frequency dividers. Each IC section is connected as a divide-bytwo circuit. The signal at U2-11 and P2-2, is one-fourth of the
crystal frequency. Half of U1 divides this frequency by two, so
the signal at U1-15 output, and P2-3, is at 1/8 of the crystal
frequency. Jumper plug P2 is then installed to route either the
divide-by-four or the divide-by-eight output to buffer-driver
U5A, pin 2. The output of U5A-7, at Test Point 14, is a TTL-level
square wave at the transmitter operating frequency.
A.5.4 External Input
An HD Radio Exciter, AM stereo generator or high-stability
external oscillator can be connected to BNC jack J2, which is
located on the Oscillator board. The external input impedance is
03/16/2009
either 50 ohms or approximately 20k ohms, depending on the
position of jumper plug P5. The high impedance input is for use
with TTL level (4 to 4.5 volt peak-to-peak square wave). With a
50 ohm input impedance, RF input levels from 0 to +25 dBm can
be accommodated. (At 50 ohms, 0 to +25 dBm is 1 mW to 316
mW, or 0.22 V rms to 4 V rms).
Amplifier Q3 and buffer/driver U5B provide a logic-level signal
to Test Point 8. Diodes CR8 and CR9 at Q3 input provide
protection against excessive input voltages.
A.5.5 Internal/External Oscillator and Combined
Transmitter Operation
Jumper plugs JP4, JP5, JP6 are used to select either the internal
oscillator, an external oscillator or Automatic. The signals at this
point are 4 to 4.5 volt peak-to-peak square wave signals (logic
level signals) at the transmitter’s operating frequency. JP4 selects the internal crystal oscillator, JP5 selects the external oscillator source and JP6 puts the board in Automatic mode.
JP1 is used to invert the signal, used only in combine mode when
needed.
When JP6 is installed then the Oscillator Board is in the AUTO
Mode. When an Ext Rf Signal is applied at J2 and a signal is
present at TP8 this causes a retriggerable monostable vibrator to
have a Logic “1” on the Q output. This output turns “ON” Q10
which then applies a Logic Low to the U10 Pin 2 when P8 is in
Position 1-2. When U10 is enabled this provides a low to U9 pin
10 and 13. Pin 8 of U9 will be low and Enable DS1 And the
CMOS switch (U8) which switches to the External RF signal.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
A-3
A.5.6 DUTY CYCLE
The output of U8 drives the duty cycle adjustment circuit. In
combined type systems this circuit is used to help NULL out
harmonics in the output spectrum.
A.5.7 AUTO/MANUAL
P7 and P8 provide active High or Active Low logic for manual
switching of the Ext RF to internal Crystals.
Switch Delay
There is an RC time Constant on the Input of U8 (CMOS switch)
this is set to 6-10ms.
A.5.8 MUTE
Anytime a switch takes place a 35-40ms pulse is generated.
Connect this line J8-2 to your transmitter Ext RF Mute connection. The RF mute occurs before the RF switch takes place to
insure that when the Ext RF signal is reapplied and it is out of
phase with the Internal crystal that damage is not done to the
transmitter.
A.5.9 EXT STATUS
When U8 (CMOS switch) is switched to the External RF Signal
J8-1 will be Low. This is an Open Collector Transistor.
wave (8-9v p-p). The output impedance of U3A is very low, and
resistor R31 sets the 50-ohm output impedance of the Oscillator
board. Resistor, R31, is one half of a voltage divider with the
other half being R16 (to ground) on the input of the Buffer
Amplifer. The output signal at J4-8 is a 4-4.5 vp-p square wave
and goes to the Oscillator Interface.
A.5.13 RF Present Output
The RF output from buffer/driver U3A is converted to positive
and negative dc voltages by peak detectors CR7-C18 and CR6C17. These dc voltages go to a fault circuits on Oscillator
Interface, through resistors R19 and R21.
If the RF output from the Oscillator board is lost, there will be
no “RF Present” voltages.
A.5.14 Power Supplies
Input voltages for the Oscillator board, from the transmitter
low-voltage power supply, are +22 volts and -22 volts, unregulated, at J1-1 and J1-4; J1-2 is “ground.” Voltage regulator U6
provides -15 volts for the crystal ovens. All positive voltages
used on the Oscillator board are shunt regulated by zener diodes,
and include +15 volts (from CR1), +9 volts (from CR13), and
+5 volts (from CR4).
A.5.9.1 Single Combined Mode
Jumper plug P4 is used to select either normal or combined
transmitter operation. For normal operation, P4-1 and P4-3 are
jumpered, and the RF signal from buffer/driver U5A or U5B is
fed to U4 pin 4. For combined operation, P4-1 and P4-2 are
connected.
A.5.10 Frequency Monitor Output
Buffer/driver U3B provides an output signal to a frequency
monitor or counter. Resistor R17 sets the driver output impedance at 50 ohms. The frequency monitor output signal, at BNC
connector J5, will be a 4-4.5 volt peak-to-peak square wave at
the transmitter operating frequency when the load impedance is
50 ohms.
A.5.11 VSWR Switching
The combiner output current sample from T4, is brought to the
Oscillator board at J3. R37 provides a 50-ohm input impedance,
and zener diodes CR11 and CR12 protect Q4 from transient
voltages. R40, R41, L4, and DIP-switch selected capacitors C30
through C33 form a phase shift network. Q4 amplifies this
phase-shifted RF sample and feeds it to pin 11 of CMOS analog
switch U4.
Integrated Circuit U4 is a CMOS analog switch, which selects
one of two RF signals. During normal operation, the signal from
P4-3 is routed through U4 to buffer-driver U3 and the transmitter
RF drive section. During a VSWR fault, U4 pin 6 goes low, and
U4 switches so that the output current sample is used as the
transmitter’s RF drive.
A.5.12 Output Buffer/Driver
Integrated circuit U3A is a logic buffer-driver. Its input, at U3-2,
is a TTL level logic signal, and its output, at U3-7, is a square
A-4
A.6 Troubleshooting -004 assembly
The following information contains general troubleshooting tips
and any precautions if applicable.
A.6.1 Oscilloscope Waveform Plots
Actual oscilloscope waveform plots of key troubleshooting
points are located at the end of this section. All plots were taken
at 100kW with no modulation at 1575kHz + 882kHz carrier
frequency.
NOTE:
Some signal magnitudes vary with carrier frequency, therefore
expect some differences in magnitude for some frequencies other
than 1575 kHz
Failure of an oscillator will result in an OSC FAULT and
possibly a LOW DRIVE FAULT
A.6.2 Measure The Power Supplies
a. Check the dc voltage at each side of F1 and F2. Both +22
volts and -22 volts should be present any time low voltage
ac power is on provided the Low Voltage Power Supply
is in the “TEST” mode. The Control multimeter will
indicate whether transmitter low voltage power supply
voltages, including +22 V and -22 V are present.
b. Check the voltages at TP1 +15Vdc, TP2 +5Vdc, TP3
+9Vdc, and P6-1 -15Vdc. If one voltage is missing, a zener
diode may be shorted or there may be a short in a circuit
supplied by that voltage.
A.6.3 Measure the VSWR-H Input
Observe the voltage at J7-5, if this voltage is more than about +1
volts when the transmitter if off, there is probably a fault on the
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Output Monitor board. (When VSWR faults are detected, logic
high pulses will appear at J7-5.)
A.6.4 Measure the RF Output
Using an oscilloscope, check for RF output at J4-8 (a convenient
place to check this is at the end of R31 which is closest to BNC
connector J5, on the left side of the board). A square wave of
4-4.5 volts peak-to-peak at the transmitter carrier frequency
should be present.
A.6.5 No Signal Present
If no RF signal is present, sequentially check the following test
points until RF is found.
a. Check the U5A output at TP5 and the frequency divider
outputs at P2-1. A 4-4.5 V p-p square wave should be
present at the transmitter frequency
b. Check the signals at Q1 and Q2 collectors. Several volts
of RF should appear at Q1 output, and Q2 output should
be a square wave of 4-4.5 volts p-p. RF frequency at these
points should be at the crystal frequency.
c. If no RF signal is present, try moving P1 to the other crystal
position.
d. If RF output returns, one crystal is defective. (If you are
going to operate with the alternate crystal, don’t forget to
change the crystal oven plug P6 as well).
A.7 Troubleshooting either assembly
These troubleshoot pertains to the front status indictors on the
treansmitter and eith er oscillator board.
A.7.1.2.1
• If the dc voltage changes from LOW to HIGH but there is
no rf output at U4-2, replace U4.
• If the voltage changes from LOW to HIGH and there is rf
output at U4-2, check U3.
• If the voltage is LOW and does not change, check the
operation of Q5.
• Measure the dc voltage at the junction of R45 and R34. If
the voltage changes from HIGH to LOW when S4 on the
LED Board is depressed, Q5 is leaky or shorted, or U4-6
input is shorted internally.
• If the dc voltage at the junction of R45 and R34 does not
change when S4 on the LED Board is depressed, check the
operation of the VSWR circuitry on the LED Board.
A.7.1.2.2
panel is Red, transmitter will not operate.
A.7.1.1 Possible Cause: Power Supplies
Check for +22 Vdc at both sides of F1. The +22 Vdc unregulated
voltage should be present when ac power is applied to the
transmitter and Low Voltage Supply circuit breaker CB2 is
turned on. The front panel multimeter will also indicate whether
the low voltage power supply voltages are present.
If the +22 Vdc is present and F1 is good, check the voltages at
TP1, TP2, and TP3. If one voltage is missing, a zener diode may
be shorted or there may be a short in a circuit supplied by that
voltage.
A.7.1.2 Possible Cause: Oscillator Sync Circuit
Using an oscilloscope, check for rf voltage At TP5. A 4-4.5 Vp-p
square wave at carrier frequency should be present.
If the rf voltage at TP5 is ok, check the output of CMOS switch
U4.
NOTE
Remember that the output to the Buffer Amplifier is held off by
CMOS switch U4 at the VSWR-H input J7-5 until the Power
Amplifier stage is turned on. Use S4 on the LED Board to check
the output of U4.
03/16/2009
U3 Defective
Using an oscilloscope, check for an rf signal at U3-2. If the rf
signal is present at U3-2 but not at U3-7, replace U3. If there is
rf present at U3-7, check the Oscillator output at J4-8.
A.7.1.2.3
Short on Output
Using an oscilloscope, check for rf output at J4-8 (a convenient
place to check is at the end of R31 closest to BNC connector J5).
A 4-4.5 Vp-p square wave at the transmitter carrier frequency
should be present.
If an rf voltage is present at U3-7 but not at J4-8, there is a short
on the Oscillator output. This could be in the cable between the
Oscillator and the Driver/Combiner motherboard, the input of
the Buffer amplifier, or the rf detection circuitry.
A.7.1.3 Possible Cause: RF Not Present at TP5
A.7.1.3.1
A.7.1 Symptom: Oscillator LED on ColorStat™
CMOS switch U4
Observe the dc voltage at U4-6 while depressing S4 on the LED
Board. The voltage should change from LOW to HIGH.
P3 or P4 Installed Incorrectly (-002 assembly only)
When the crystal oscillator on the Oscillator is used, the jumper
plugs must be installed from P3-1 to P3-3, and from P4-1 to P4-3.
When an external oscillator is used, the jumper plugs must be
installed from P3-1 to P3-2, and from P4-1 to P4-2.
If P3 and P4 are installed correctly, and the crystal oscillator is
used, continue with the list of possible causes below.
A.7.1.3.2
Crystal Failure
Move P1 to the other crystal position. If rf output returns, one
crystal is defective. If you operate with the alternate crystal,
change the crystal oven plug P6 to the alternate crystal.
A.7.1.3.3
Q1, Q2 faulty
Using an oscilloscope, check the signals at Q1 and Q2 collectors.
A sinewave of rf should be present at the output of Q1. The
output of Q2 output should be a square wave at 4-4.5 Vp-p. The
RF frequency at these points should be at the crystal frequency.
A.7.1.3.4
U1, U2 faulty
Check the frequency divider outputs at P2-2 and P2-3 for a 4-4.5
Vp-p square wave. Each IC section should divide the frequency
by two. Faults in a divider IC section will normally cause the IC
output to go to ground or +Vcc supply voltage.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
A-5
A.7.1.3.5
U5 faulty
The output of U5-7 should be 4-4.5 Vp-p square wave, and can
be checked at P3-3.
A.7.2 Symptom: No RF Output, External Oscillator
Used
A.7.2.1 Possible Cause: RF Input From External Oscillator
The fault could be either in the external oscillator or in coaxial
cables carrying the signal. Check for output from the external
oscillator, then trace the signal through each cable connection
point.
of these dc voltages are missing, check and/or replace the diode(s). Loss of one or both dc voltages will cause a RED
“OSCILLATOR” status indication. If voltage is present at one
side of R19 or R21 but not at the other side, a resistor failure or
a short after J7 is indicated. (In this case, the transmitter will
remain ON.)
If you measured correct dc voltages in the previous step, the red
“OSCILLATOR” Status LED indication is caused by a problem
on the LED Board or an open or short in an interconnecting cable.
Refer to SECTION Q, LED Board, and SECTION VI, Troubleshooting, for additional information.
A.7.2.2 Possible Cause: External Input Impedance
When P5 is jumpered from 1 to 3, the external input is terminated
in 50 Ohms. For a 50 Ohm input, 0.23 Vrms to 4 Vrms should
be present at P5-1. For a TTL input, 4-4.5 Vp-p should be present
at P5-1 with P5 jumpered from 1 to 2.
A.7.2.3 Possible Cause: Q3 or U5 faulty
Using an oscilloscope, check the rf signal level at Q3 collector
and at P3-2. Both should be 4-4.5 Vp-p.
A.7.3 Symptom: Frequency Stability.
A.7.3.1 Possible Cause: Plug P6.
Make certain that both P1 and P6 are in the same position
(jumper from 1 to 3 on both, or from 1 to 2 on both).
A.7.3.2 Possible Cause: Crystal Oven Failure
The crystal oven which is operating should be hot.
A.7.3.3 Possible Cause: No -15 Vdc Supply
Check for -15 Vdc at P6-1. If not present, check both ends of F2
for -22 Vdc. If F2 is open, replace it. If the fuse opens again, U6
is probably defective.
A.7.3.4 Possible Cause: Defective Crystal
Defective crystals may operate off frequency. If one crystal can
be adjusted to the correct frequency but the other cannot, the
off-frequency crystal is probably defective.
A.7.4 Symptom: Output At Incorrect Frequency
A.7.4.1 Possible Cause: Frequency Divider Jumper Plug P2
Check the position of the P2. The crystal frequency will be
divided by four if P2 is from 1-2, and will be divided by eight if
P2 is from 1-3. Check your crystal frequency and the jumper
position.
A.7.4.2 Possible Cause: Frequency Divider Fault
Normally a frequency divider fault will result in complete loss
of rf at P2-1. The output of a frequency divider section will go
to either 0 Vdc or to +5 Vdc. Using an oscilloscope, check the
oscillator frequency at Q2 collector, and divider frequencies at
P2. Frequency at P2-2 should be 1/4 the oscillator frequency and
at P2-3, should be 1/8 the oscillator frequency.
A.7.5 Symptom: Oscillator LED on ColorStat™ panel
is Red but transmitter operation is normal.
A.7.5.1 Possible Cause: RF Present circuit
CR6 and CR7 “RF Present Detectors.” Check for +4 to +5 Vdc
at CR7 cathode and for -4 to -5 Vdc at CR6 anode. If a normal
rf level is present at the Oscillator board output but one or both
A-6
A.8 Oscillator Alignment
A.8.1 Carrier Detect Adjustments
Depending on your Transmitters Freq R64 must be adjusted for
proper Carrier loss Detection. Refer to Table A-1.
NOTE
R64 must be adjusted with Power off. Place a Multimeter on
TP13 and R70. Make sure you are on the junction of R70 and
R64. To achieve this place your meter on either side of R70. The
side with 5k Ohm less is the side you want.
This adjustment is used to detect the loss of the External RF
signal. When RF is lost for 5-8 cycles U7 will be set causing the
“Q” output to go low. This in turn causes the CMOS switch to
switch to the Internal Crystal.
A.8.2 Oscillator Frequency Fine Adjustment
a. Connect a frequency counter or frequency monitor to the
Oscillator to the Oscillator board Frequency Monitor Output (BNC Jack J5).
b. Select the crystal to be adjusted, make sure its oven is
operating and warmed up.
c. Adjust C1 (for crystal Y1) or C3 (for crystal Y2) for the
desired frequency. Only a small range of adjustment of
frequency is possible.
NOTE:
Crystal jumper plug P1 and Oven jumper J6 must both be in the
same position during adjustment or operation. Do not adjust frequency for either crystal until its oven has had sufficient time to
warm up, allowing at least 15 minutes.
A.8.3 Oscillator Sync Adjustment
Using a dual trace scope:
a.
b.
c.
d.
Connect channel 1 to TP5.
Connect channel 2 to TP4.
Sync the scope to channel 1.
Set the sweep speed on the scope to display one or two
cycles of RF.
e. Operate the transmitter at maximum TPO, and note that at
this time, channel 2 will also have a 5Vp-p squarewave
displayed.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Refer to Table A-2 for Jumper configuration.
f. If the positive going edges of the two waveforms are lined
up, no further adjustments are required.
g. If the trace on channel 2 is not aligned in phase, adjust L4
to bring them into phase with each other.
h. If by adjusting L4 the two waveforms will not line up, then
different combinations of capacitance as selected by S1
can be switched in to provide various amounts of phase
shift.
i. If it appears that the two signals are 180 degrees apart then
the plug P3 can be reversed at J3. This should not be the
case if the board is simply being replaced assuming the
plug position was noted before removal.
A.9.1.1 Additional Installation Steps for HD Radio ONLY
Refer to Fig.1 in Application Note following parts list for HD
Radio setup.
a. Connect Ext RF Mute from A17J8-2 Oscillator board to
the following:
Model
Location Connection
Notes
DX10/15/25/50
TB1
TB1-23 Connect TB1-21 to
TB1-11 for +15V
Common
b. Connect External Failsafe as follows
1. HD Rack TB1-23 to DX Oscillator Board J6-1
2. HD Rack TB1-24 to DX Oscillator Board J6-2
c. Run and dress cable so that it does not interfere with doors
that open and close.
NOTE:
When switching in different values of capacitance, try to use the
least amount of capacitance (S1-1, 2, and 3) to achieve phase
alignment of the two signals. If too much capacitance is used
there may not be enough signal input to produce a signal at TP4.
A.9.2 Final Adjustments
Adjustments are now required once the new board has been
installed and made operational.
A.9 Oscillator Replacement
a.
b.
c.
d.
A.9.1 Installation
For Replacement install new Oscillator board and note switch
and cable connections.
Set Dip switches the same. Note they will be checked after turn
“ON.”
Carrier Detect Setup (see A.7.1)
Carrier Frequency Adjust C1 and C3 (see A.7.2)
Oscillator Sync Adjustment S1 and L4 (see A.7.3)
Turn Transmitter off and set the Jumpers for your Configuration Internal, External, or Auto mode. (JP4, 5, 6)
Remove Crystals and reinstall crystal in new Oscillator board.
Table A-1
Carrier loss Detection R64 adjustment.
Freq
(kHz)
Ohms
(k)
500
540
640
740
840
940
1040
1140
1240
1340
1440
1540
1640
1740
23
21
17
14
11
9
8
7
6
5
4
4
3
3
Table A-2 Oscillator Jumper Positions
Oscillator Board
Jumper #
P1
P2
P4
P5
P6
P7
P8
JP4 (see note at right)
JP5 (see note at right)
JP6 (see note at right)
03/16/2009
Jumper Position Description
Pins 1-2
Pins 1-3
Activates Crystal Y1
Activates Crystal Y2
For 1251kHz & Above, selects divide by 4
For 1250kHz and below, selects divide by 8
Can be used for Combined Transmitter Operation
Selects Normal Single Transmitter Operation
Sets Input Impedance for External Oscillator.
Sets input Z for External Oscillator Input at 50
Input at 20k Ohms for TTL Levels
Ohms for 0-25dBm Input
Activates Oven for Crystal Y1
Activates Oven for Crystal Y2
+5V External Failsafe Disabled
+5V External Failsafe Enabled
External Carrier Detect ON
External Carrier Detect OFF
Selects External Oscillator Inputs from J2
NOTE: ONLY one of these three jumpers can be
Selects Internal Crystal
installed at a time
Uses CMOS switch of RF Signals
888-2247-006
WARNING: Disconnect primary power prior to servicing.
A-7
Q1 Base
-004 assembly
P2-1
-004 assembly
A-8
Q2 Collector
-004 assembly
Upper Trace CH2 TP5
Lower Trace CH1 TP4
-004 assembly
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
J4-8
-004 assembly
J5-1
-004 assembly
J3-1
-004 assembly
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
A-9
A-10
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section B
Buffer Amplifier (A16)
B.1 Introduction
This section includes a description of the Buffer Amplifier, and
troubleshooting information. The Buffer Amplifier plugs into
the Driver Combiner/Motherboard, and is accessible from the
front of the transmitter.
B.1.1 Principles of Operation
The Buffer Amplifier includes three amplifier stages. The buffer-driver U1 takes the TTL-level output from the Oscillator
Board and drives the push-pull second stage, consisting of Q1,
Q2 and associated components. The third stage consists of
MOSFET’s Q3 and Q4 which provide the rf output to drive the
Predriver.
Refer to SECTION V, Maintenance, for pc board maintenance
procedures. There are no adjustments on this module.
B.2 Circuit Description
Refer to the Buffer Amplifier Schematic, 849-7855-099, in the
Drawing Package.
B.2.1 Buffer Amplifier Supply Voltage
The +30Vdc supply is used for the Buffer Amplifier and is
adjusted by the Buffer Voltage ADJ potentiometer R2 in the
Driver Compartment. The dc input is fused by F3, filtered, and
used for the third stage MOSFET transistors. Red LED DS3 will
illuminate if F3 opens and will be visible through the interlocked
door inside the Driver Control Compartment. The supply voltage
is also regulated to +15Vdc by zener diode CR5 for driver
amplifier U1 and second stage transistors Q1 and Q2.
B.2.2 First RF Amplifier Stage (U1)
The first rf amplifier consists of a CMOS clock driver IC used
as a buffer-driver stage to convert the TTL-level input from the
Oscillator into a higher level signal to drive Q1-Q2.
B.2.5 Output Coupling Network
The output of the Q3-Q4 amplifier stage is coupled to the
Predriver input through broad-band coupling network C3, R8R11 and L2.
B.2.6 Buffer Amplifier RF Sense
The “Buffer Amplifier” indicator LED on the ColorStat™ panel
is driven by an rf detector on the Driver Combiner/Motherboard
and logic circuits on the LED Board.
Refer to SECTION D, Driver Combiner/Motherboard, and SECTION Q, LED Board.
B.2.7 Predriver Supply
The +60 Vdc supply is used for the Predriver amplifier and is
adjusted by Predriver Voltage ADJ potentiometer R1 in the
Driver Compartment.
The Predriver DC IN is fused on the Buffer Amplifier pc board
by F1 and F2. Red LED’s DS1 and DS2 will illuminate if F1 or
F2 opens. These can be observed through the interlocked door
in the Driver Compartment.
Refer to SECTION D, Driver Combiner/Motherboard and to
SECTION C, RF Amplifier Modules, for additional information
on the Predriver.
B.3 Troubleshooting
Troubleshooting consists of isolating an rf drive problem to the
Buffer Amplifier Board, using the LED indicators. The easiest
way to check buffer amplifier operation is to substitute a spare
board if one is available.
B.3.1 Symptom: Buffer Amplifier LED on Color-
Stat™ panel is Red, transmitter will not operate.
B.3.1.1 Possible Cause: Component failure
B.2.3 Second RF Amplifier Stage (Q1 and Q2)
Transistors Q1 and Q2 operate as a high-efficiency switching
amplifier, with square-wave input and output signals. The output, at the junction of Q1 and Q2 emitters, switches between
ground and the supply voltage. This stage provides rf drive to
the output transistors Q3 and Q4 through a series tuned coupling
network C2, L1 and R5,and phase-splitting transformer T1.
LED indicators will illuminate when a fuse is open, if the
associated Low Voltage supply is present. Three indicators are
visible through the interlocked RF Amp access door inside the
Driver Compartment:
B.2.4 Third RF Amplifier Stage (Q3 and Q4)
This rf amplifier stage drives the Predriver and consists of two
power MOSFET’s Q3 and Q4. The two rf drive signals to the
MOSFET gates are 180° out of phase (note the dots, indicating
phase of each secondary winding on T1). Transistors Q3 and Q4
switch between ground and the dc supply. Diodes CR3 and CR4
protect the MOSFET gates against overvoltages.
If the Buffer Amp fuse indicator is illuminated, check the Buffer
Amplifier Board for signs of overheated components, or damage
to printed circuit board traces. Check the socket on the motherboard for damage.
03/16/2009
• DS1 (F1) - PREDRIVER A
• DS2 (F2) - PREDRIVER B
• DS3 (F3) - BUFFER AMP
Buffer Amplifier Board component checks can be made with the
Buffer Amplifier Board removed from the transmitter. Refer to
SECTION VI, Troubleshooting, for information on checking
MOSFET’s.
888-2247-006
WARNING: Disconnect primary power proir to servicing.
B-1
Back-to-back zener diodes CR3 and CR4 should indicate a low
leakage current in either direction; if one of the diodes is shorted,
they will look like a single diode with an ohmmeter check or
“diode test” function on a digital multimeter. Note that CR3 and
CR4 are each in parallel with a 10 Ohm resistor and low resistance toroidal transformer winding, so in-circuit checks are not
possible. One end will have to be removed from the circuit to
test.
B.3.1.2 Possible Cause: Coaxial Cable or Connector Fault
With all power removed from the transmitter, you can remove
P4 from the Oscillator Board and check for a 50 Ohm resistance
B-2
into P4-8 and 9; this indicates that the coaxial cable and connectors are good.
B.3.2 Symptom: Buffer Amplifier LED on Color-
Stat™ panel is Red, transmitter will operate.
If the transmitter will operate, but the ColorStat™ panel LED is
red, there is a detector failure on the Driver Combiner/Motherboard or a fault circuit failure on the LED Board. Refer to
SECTION D, Driver Combiner/Motherboard and SECTION Q,
LED Board, for troubleshooting information.
888-2247-006
WARNING: Disconnect primary power proir to servicing.
03/16/2009
Section C
RF Amplifier
C.1 Introduction
This section includes a description of the RF amplifier module,
and troubleshooting information.
The transmitter uses a total of 52 “plug-in” RF amplifier modules. One module is used in the Predriver stage, three are used
in the Driver stage (Driver 1 through Driver 3) and 48 are used
in the Power Amplifier stage (RF1 through RF48).
Any RF amplifier module can be used in the Predriver, Driver,
or Power Amplifier position. Modules can be exchanged with no
effect on transmitter performance. If a PA Module fails, FlexPatch™ can be used to replace it with another PA Module
without turning the transmitter OFF. Refer to “Using FlexPatch™ To Replace A Failed PA Amplifier” in the Troubleshooting or Emergency Operating section, for more
information.
CAUTION
ALL MOSFETS MUST BE IN PLACE ON ALL MODULES IN ALL
POSITIONS (RF1-RF48, D1-D3 AND PREDRIVER), EVEN IF SOME
MODULES HAVE SHORTED MOSFETS. FAILURE TO OBSERVE
THIS PRECAUTION WILL RESULT IN DAMAGE TO COMBINER
TRANSFORMER TOROIDAL CORES.
All RF amplifier modules plug into combiner/motherboards, and
are accessible from the front of the transmitter. The Predriver
and Driver Modules plug in to the Driver Combiner/Motherboard. Power Amplifier stage modules RF1 through RF48 plug
in to the Binary Combiner/Motherboard and seven Main Combiner/Motherboards. This section describes only the RF amplifier module.
Refer to the Maintenance section, for pc board maintenance
procedures. There are no adjustments on this board.
The Driver section and Power Amplifier section are described
in the Overall System Theory.
C.2 Principles of Operation
Refer to the simplified diagrams C-1 through C-5.
Each RF amplifier module is a class D switching amplifier, using
four N-channel power MOSFETs in a bridge configuration. This
configuration is referred to as a QUAD. The quad is made up of
two sections: Section A includes Q1 and Q3; section B includes
Q2 and Q4. Power MOSFETs are in flat plastic packages, and
are mounted on heat sinks.
C.2.1 RF Amplifier: Basic Theory Of Operation
Figure C-1 is a simplified functional diagram of an RF amplifier
module. Each section of the module consists of two MOSFETs
in series. Each pair of MOSFETs is alternately driven into cutoff
and into saturation, acting as a switch. The RF drive signals to
the two MOSFETs in a section are 180° out of phase, so that
03/16/2009
when the upper pair is on (saturated) the lower pair is off (cut
off). When the upper pair is off the lower pair is on. The output
is switched between ground (about zero Volts) and the positive
supply voltage at an RF rate.
Amplifier efficiency is high because each MOSFET switches
between cutoff and saturation in a very short time. Dissipation
is low in both states. The devices switch quickly through their
linear operating region, where power dissipation is high, so that
average power dissipation is low.
C.2.2 RF Amplifier: Half Quad Configuration
The RF amplifier was designed to have a separate supply voltage
and RF drive inputs to allow the A half to operate independently
of the B half. This feature is utilized in Driver 1A and 1B.
Independent supply voltages for Driver 1A and 1B are supplied
by the Driver Supply regulator.
Figure C-2 shows the MOSFETs as switches, for section A.
Section B is identical in operation, except Q2 and Q4 are used.
The square wave RF output waveform, at the junction of Q1
source and Q3 drain, is the carrier frequency of the transmitter.
C.2.3 RF Amplifier: Full Quad Configuration
All RF amplifier modules except Driver Module D1 operate in
a full-quad configuration: section A output and section B output
are connected to opposite ends of a combiner transformer primary winding. This is equivalent to the classical push-pull
configuration.
Figure C-3 shows the four MOSFETs as switches. The phase of
the RF drive signals is such that only two configurations are
possible for the switches (unless a MOSFET is shorted). During
one half of the RF cycle, Q1 and Q4 are both driven to cutoff
and Q2 and Q3 are saturated. During the other half of the cycle,
Q1 and Q4 are saturated, and Q2 and Q3 are cut off.
This switching action effectively applies the full supply voltage
to the combiner transformer primary winding across C8. Each
doubled push-pull amplifier produces a square wave output, but
the two sets of amplifier square waves are 180° out of phase.
The square wave peak-to-peak amplitude across the transformer
primary is about two times the supply voltage and will have some
“ringing” because of the reactive load.
A capacitor is placed in series with the transformer winding to
prevent a direct current path to ground if a MOSFET shorts.
C.2.4 RF Amplifier Module On/Off Control Circuit
In the Predriver and the Driver stage, the RF amplifier modules
are always turned ON when the transmitter is operating. In the
Power Amplifier stage, however, modules are turned ON and
OFF to change the power and to modulate the carrier.
Figure C-4 is simplified diagram that explains the control circuit
operation. The control section on the RF amplifier module
affects RF drive to Q3 and Q4.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
C-1
Figure C-1
RF Amplifier Module, simplified diagram.
Figure C-2
RF Amplifier operation, half quad configuration.
Figure C-3
RF Amplifier operation, full quad configuration.
C-2
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure C-4
RF Amplifier Module control section operation.
A TTL “LOW” control signal from the Modulation Encoder will
switch PNP transistor Q5 ON and switch NPN transistor Q7
OFF. A TTL “HIGH” control signal will turn Q5 OFF and Q7
ON.
Figure C-4b. shows the equivalent RF drive circuit when the RF
amplifier is ON. Transistor Q5 is ON, which completes the RF
ground path through the secondary of transformer T1 and provides RF drive to the gate of MOSFET Q3. The RF drive circuit
for Q4 is the same, except that the RF ground path is through
control transistor Q6.
Figure C-4c. shows the equivalent RF drive circuit when the RF
amplifier is OFF. Transistor Q7 is ON, which clamps the positive
half-cycle of the RF drive from transformer T1 slightly above
ground. This prevents MOSFET Q3 from switching ON. The RF
drive circuit for Q4 is the same, except that CR8, Q6, and
associated components are used.
C.2.5 RF Transformer Primary Current: Amplifier
Off
When an amplifier module is OFF, there is no current flow from
the supply through the combiner transformer primary and the
module does not supply any power to the combiner. Current will
still flow through the combiner secondary, however, unless the
total combiner RF output is zero. This combiner current will
induce RF voltages in the toroidal transformer primary windings
on all inactive modules.
If the combiner transformer primary sees an open circuit, induced voltages can damage amplifier MOSFETs, and high RF
voltages in the unloaded primary can cause an arc which can
crack the toroid. The “quad” amplifier configuration and reverse
03/16/2009
diodes in the MOSFETs provide an RF current path, as described
in the next paragraphs.
This explanation is based on simplified diagram, Figure C-5.
When the polarity of the induced voltage in the combiner transformer is as shown in the diagram, Q1 is OFF and Q2 is ON. A
low-impedance RF current path is available through the reverse
diodes in Q1, and bypass capacitors C1, C3, C4, and C2.
When the polarity of the voltage induced in the transformer
winding reverses, Q1 turn ON and Q2 will turn OFF. The current
flow will now be through the reverse diodes in Q2.
C.2.6 Oscillator Sync Signal
When the VSWR protection circuits turn all RF amplifiers in the
Power Amplifier stage OFF, “ringing currents” will continue to
flow in the output network, and in the RF combiner secondary,
for several cycles. For maximum MOSFET reliability during a
high VSWR, Q1 and Q2 in all PA Modules must switch in phase
with output network ringing currents. This is accomplished with
the Oscillator Sync circuitry, including an output network current sample and circuits on the Oscillator.
C.3 Circuit Description
Refer to Schematic 839-6208-246 in the Drawing Package.
C.3.1 Supply Voltage
The supply voltage for section A enters the module through
P1-23, 24, 25 and 26; the supply voltage for section B enters the
module through P1-29, 30, 31, and 32. The low side of each RF
quad amplifier returns to ground. The supply voltage is +230
Vdc for the “BIG STEP” PA Modules; +115 Vdc and +60 Vdc
888-2247-006
WARNING: Disconnect primary power prior to servicing.
C-3
Figure C-5
RF Amplifier Module: Combiner Transformer primary winding
current flow with module OFF.
for “BINARY” PA Modules; +115 Vdc Driver Modules; and
+60 Vdc for the Predriver Module.
The supplies then pass through RF chokes L1 and L2 and are
fused by F1 and F2. If a fuse for a half-quad opens (typically,
because of MOSFET failure), the other half-quad will continue
to operate. For modules used in a full-quad configuration, the
module will continue to deliver a reduced RF power level (at half
the peak-to-peak RF voltage across the combiner output transformer primary).
The drains of Q1 and Q2 are bypassed to ground by C1 and C3,
and C2 and C4.
C.3.2 LED Indicators
Red LED indicators DS1 and DS2 illuminate if there is a blown
fuse on the module.
C.3.3 Cable Interlock
The cable interlock control signal from the Modulation Encoder
loops through the RF amplifier on pins P1-35/36 and P1-37/38.
Refer to SECTION L, Modulation Encoder, for a description of
the Cable Interlock circuitry.
C.3.4 RF Drive
RF drive is fed to transformers T1 and T2. One RF drive
transformer is used for each half-quad. RF drive for section A
enters the module at P1-49/50; RF drive for section B enters at
P1-53/54. Individual coaxial cables from the RF Drive Splitter
feed RF drive to the A and B section of each module so that if
one section fails the drive to the other section will not be affected.
A network in parallel with each RF drive transformer broadbands
the input circuit, so that no component changes are required for
operation at any frequency in the broadcast band. For T1, this
network consists of L3, R3 and R5; for T2, the network consists
of L4, R4 and R6.
C-4
Each RF drive transformer has two pairs of secondary windings,
which provide two pairs of drive signals, 180° out of phase, for
the upper and lower MOSFET pairs in each half-quad. On the
schematic diagram, small circles at one end of each transformer
winding indicate RF phasing.
Back-to-back zener diodes CR1, CR2, CR3, and CR4 protect the
MOSFET gates against overvoltages, including possible transient voltages.
When modules are used in the Power Amplifier stage, RF drive
is provided by the RF Drive Splitter. All RF drive cables are the
same length, so that RF drive phase is the same to all modules.
The RF amplifier schematic diagram indicates proper RF levels.
C.3.5 Control Section
Control signals enter at P1-45/46. Transistors Q5, Q6 and Q7 are
the ON-OFF control transistors for the module. A “TTL HIGH”
voltage at P1-45/46 (+4 Volts or more) turns the amplifier OFF.
A negative voltage at P1-45/46 (-2 to -4 Volts) turns the amplifier
ON.
For RF amplifiers used in the Power Amplifier stage, control
signals from the Modulation Encoder switch between “TTL
HIGH” and a small negative voltage to turn RF amplifier modules ON and OFF. The negative voltage is derived from the Bsupply output of the DC Regulator. Because the switching characteristics of the modules change, depending on the number of
modules on at any instant, this voltage will vary with modulation
and change the turn-on and turn-off times of the modules.
For RF amplifiers used in the Driver stage, a fixed -5 Vdc control
voltage from the Driver Encoder/Temp Sense Board keeps the
modules ON.
When the amplifier is turned ON, Q5 and Q6 and diodes CR5
and CR6 provide conduction paths for the RF drive signal.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
When the amplifier is turned OFF, transistor Q7 conducts and
the RF drive signal is clamped at ground through CR7 and CR8.
The positive voltage required to turn on the power MOSFETs is
several Volts, much larger than the junction drop across the
diodes.
C.3.6 RF Output
The output signal for each half-quad appears at the junction of
the MOSFETs. Section A output leaves the module through
P1-1/2/3/4; section B output leaves the module through P17/8/9/10. Capacitor C8 provides dc isolation between the outputs.
C.4 Troubleshooting
C.4.1 Symptom: Blown Fuse Indicator Illuminated
C.4.1.1 Possible Cause: Shorted MOSFETS
An open fuse probably indicates that one or both MOSFETs in
that half-quad is defective. You can continue to operate the
transmitter until a normal shut-down period, the open fuse will
prevent further damage. FlexPatch™ can be used to substitute
for a failed module without shutting the transmitter OFF, to
restore normal transmitter performance. Refer to SECTION VI,
Troubleshooting, and SECTION L, Modulation Encoder, for
information on using FlexPatch™ to substitute PA Modules.
The MOSFETs will have to be removed from the circuit in order
to perform the following test.
C.4.1.1.1
Handling MOSFETs
Due to the fragile nature of the gate of a MOSFET, special care
in their handling is required. The gate junction may be destroyed
by static electricity if the static electricity is allowed to discharge
through the MOSFET. For example, walking across a carpet to
pick up a MOSFET that is not protected by antistatic packaging
could result in the destruction of the MOSFET. A static charge
could build up on a person walking across the carpet. This static
charge will eventually have to be discharged. Discharging to the
MOSFET could damage the MOSFET. Transistors which are in
circuit are immune to this damage. The MOSFET transistors are
shipped in antistatic packaging. The transistors should remain in
this packaging until they are to be used or tested.
C.4.1.1.2
Removing MOSFETs
• Remove the heatsinks one at a time starting with the outer
most sink. Break seals on transistor pads as each pair is
exposed.
• Unsolder the MOSFETS from the pc board.
C.4.1.1.3
Testing MOSFETS
The MOSFETs may be checked using an ohmmeter with a
battery voltage between 3 Volts and 18 Volts. A Simpson 260,
which uses a 9 Volt battery on the Rx10k scale, works quite well.
This test will show how a MOSFET can be switched “on” and
“off” by charging and discharging the gate of the MOSFET.
Place the transistor face up on a non-conducting surface. Connect the positive lead of the ohmmeter to the drain (center lead)
of the transistor and connect the negative lead to source (right
lead). Alternately touch a jumper from gate to source and then
from gate to drain to turn the MOSFET “on” and “off”. The
ohmmeter should read towards infinity (at least 2 meg Ohms)
when the MOSFET is switched “off” and less than 90k Ohms
when the MOSFET is switched“on”. Do not touch the leads
when performing this test.
When repairing an RF amplifier, it is recommended that both
MOSFETs in the failed half of a module be replaced, even
though only one of the MOSFETs are found to be shorted. The
remaining MOSFET may have been stressed internally and may
fail when supply voltage is reapplied. A blown fuse on one half
of the amplifier does not effect the other half.
MOSFETs that appear to be undamaged after testing can be kept
as spares for use if new replacements are not available. Also keep
in mind that the amplifiers used in the Driver and PA are identical
except that the Driver amplifiers operate at half voltage. This
allows you to rotate a repaired module into the Driver position
if so desired.
C.4.1.1.4
Replacing MOSFETS
• Inspect all the transistor pads for any damage that may have
•
•
•
•
occurred when the transistors were removed from the
heatsinks. Replace any damaged pad.
Insert the transistors into the pc board. Do not solder leads
until heatsinks are in place.
Reattach heatsinks in reverse order as they were removed.
Tighten heatsink and pc board screws first and then tighten
transistor screws (torque to 3 inch-lbs).
Solder transistor leads and trim.
Replace blown fuse(s).
NOTE
DO NOT TRY TO PRY THE HEATSINK AWAY FROM THE
PC BOARD BEFORE REMOVING TRANSISTORS FROM
THE HEATSINK. THE PC BOARD MAY BE DAMAGED
AND THE HEATSINK MAY DISTORT.
• Remove all the screws from heatsinks and transistors. In
most cases, the transistor will stick to the heatsink because
of the seal created by the transistor pad. This seal will have
to be broken before a heatsink can be removed. Remove
the screw holding the MOSFET to the heatsink and gently
pry the transistor away from its heatsink.
03/16/2009
Figure C-6
MOSFET configuration
888-2247-006
WARNING: Disconnect primary power prior to servicing.
C-5
C.4.1.2 Checking RF Module Operation
The most common method of troubleshooting an RF amplifier
after a failure is to put the repaired amplifier in a known working
step, i.e. step 1 through 5, and to put the working amplifier where
the failure first occurred. This is known as module swapping and
although it is less conservative, it will quickly tell you whether
the amplifier fault was caused by the position it was in or by the
amplifier itself.
After an RF amplifier has failed, some thought should be given
as to what caused the failure before a replacement or repaired
amplifier is put back in place and the transmitter is turned back
on. For example:
2. Is the amplifier receiving a proper ON/OFF control
signal from the Modulation Encoder?
3. Did something short at the output of the amplifier?
4. After the MOSFETs were replaced, is there something
else on the amplifier that may have been damaged?
Even though most causes for an RF amplifier failure are related
to a power MOSFET breaking down, it is recommended that a
more conservative approach be taken so as not to fail a second
amplifier in the same position or fail the repaired amplifier a
second time.
For information on troubleshooting repeated PA Module failures, refer to the Troubleshooting section.
1. Are the A and the B halves of the amplifier receiving
the proper drive?
C-6
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section D
Driver Combiner/Motherboard (A14)
D.1 Introduction
This section describes the Driver Combiner and Motherboard,
and includes a description of the board, parts list, and troubleshooting information.
The Driver Combiner/Motherboard is located at the top of the
center interlocked compartment. The Driver Combiner/Motherboard is accessible from the back of the transmitter. To access
the board, remove the center panel on the back of the transmitter.
The Driver Combiner/Motherboard contains the RF driver section, except for two variable inductors used for tuning (L1 and
L2). The buffer amplifier, predriver, and three RF driver modules
plug into printed circuit board edge connector sockets on this
motherboard.
D.2 Principles of Operation
The description in this section is based on the Driver Combiner/Motherboard Schematic Diagram (839-6208-226) and the
simplified schematic diagram, Figure D-1. The driver combiner/motherboard printed circuit board includes:
a. Predriver, Section A/Section B switch (A14S1)
b. Impedance matching circuits between RF drive sub-sections
c. RF drive splitter for Driver section
d. RF Driver output combiner
e. Driver Transformer ratio adjustments
f. Driver coarse tuning adjustments
g. Feed-forward Neutralization in/out jumper
h. Neutralization Phase adjustment
i. Neutralization Amplitude adjustments
j. Dc power distribution, and metering circuits for the buffer,
predriver, and RF driver sections.
The board contains sockets for the following plug-in modules:
1. Buffer Amplifier, A16
2. Predriver, A40
3. RF Driver modules, A41, A42, and A43.
Refer to the following sections of this Technical Manual for
descriptions of printed circuit boards which plug into the driver
combiner/motherboard:
• Section B, Buffer Amplifier A16.
• Section C, RF Amplifiers (modules A40, A41, A42 and
A43, used in the predriver and RF driver)
• Section E, Driver Supply Regulator (regulated supply for
section 1 of the RF driver).
D.2.1 RF Driver Section
The RF driver section of the DX-10 accepts a TTL-level input
signal, at the transmitter’s operating frequency, from the Oscil03/16/2009
lator board. The RF driver section includes several stages of
amplification, to provide enough RF drive power for the 48
power amplifier modules.
The RF driver stage normally operates below its power capability. It is capable of providing the additional RF drive power
required when power amplifier modules fail.
D.2.2 Buffer Amplifier
The signal from Oscillator Board A17 enters the driver motherboard at J1, and is routed directly to the Buffer Amplifier RF
input (J6, terminals 39, 40, 41 and 42).
The Buffer Amplifier supply voltage is +30 volts, from the
DX-10’s Low Voltage DC supply (which is shown on the DX-10
Overall Schematic). The +30 volts goes through resistors
A14R27, R28 and R29, and then to the buffer amplifier.
The buffer amplifier’s RF output enters the driver motherboard
at J6-5 and 6, and is routed to one section of DPDT switch
A14S1. The RF output signal also goes to a peak detector (diode
CR6, and R4, C1, and R3). Zener diode CR3 limits the detector’s
maximum dc output voltage. The peak detector provides a buffer
amplifier “RF sense” signal to fault and overload circuits on LED
board A32. When RF is present at the buffer amplifier output,
the Buffer Amplifier LED on the DX-10 Status Panel will be
green; when RF is not present, the LED will indicate red.
D.2.3 Predriver
The predriver uses RF Amplifier module A40. Only one halfquad is used at a time; switch S1 on the driver motherboard
selects section A or section B of the predriver module.
The predriver’s RF output passes through series-tuned network
L1 and A14C3-C4-C5 to the input of the drive splitter. Jumper
plug J14 is used to add additional capacitance for lower frequencies. L1 is simply tuned for maximum RF drive to the driver
section. (Adjustment L1 is located at the rear of the non-interlocked compartment, above the modules). Refer to the paragraphs on tune-up/frequency change procedure in Section V,
Maintenance, for adjustment procedures.
The supply voltage for the pre-driver, at J15-1, goes through
metering circuits and through fuses on buffer amplifier A16 to
pre-driver socket J10.
Supply voltage for the pre-driver is adjustable from +30 to +60
Vdc, using R1 (located in the non-interlocked compartment, at
the top of the rear panel) and jumper plug P15/J15 on the driver
combiner/mother-board. This adjustment provides proper RF
drive level to the RF driver section. In general, more supply
voltage is required at lower transmitter frequencies. (Refer to the
paragraphs on tune-up/frequency change procedure in Section
V, Maintenance, for an adjustment procedure).
The selected voltage at the “common” terminal on J15 goes
through R14 to buffer amplifier board A16, at J6-25 and 26. Two
pre-driver supply fuses are located on the buffer amplifier board,
888-2247-006
WARNING: Disconnect primary power prior to servicing.
D-1
Figure D-1
Simplified Diagram, Driver Combiner Motherboard.
D-2
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
one for pre-driver Section A and another for pre-driver Section
B. This arrangement removes the pre-driver supply voltage if the
buffer amplifier board is removed for any reason.
D.2.4 Predriver Metering
The voltage drop across R14 depends on the pre-driver current,
and when the RF multimeter is switched to the “Predriver IDC”
position, it acts as a voltmeter, measuring this voltage drop; R13
and R15 are the voltmeter’s series multiplier resistors. Resistor
R16 is the voltmeter multiplier resistor when the multimeter is
switched to the “Predriver +VDC” position.
D.2.5 Driver Splitter
The Drive Splitter consists of transformers, T1 through T6. Each
transformer is wound on a ferrite toroid, and is broadbanded with
a capacitor-resistor network across the transformer secondary.
The output of each section of the drive splitter goes to a driver
section’s RF input, at J7, J8 or J9. An additional L-C network is
in series with the output of T5, refer to the paragraphs on
“Neutralization” below for a description of this network.
D.2.6 RF Amp/Driver RF Sense
The RF voltage at the secondary of T6 is also fed to an RF peak
detector (CR5, R5, R12, and C2). Zener diode CR4 limits the dc
output voltage from this peak detector. The peak detector’s dc
output voltage is the Predriver RF Sense signal to fault and
overload signals on LED board A32. When this dc voltage is
present, the “PREDRIVER” LED on the Status Panel will be
green; when the voltage is absent, the LED will be red.
D.2.7 RF Driver
The RF Driver consists of three RF amplifier modules, A41, A42
and A43 (refer to section C for a description of RF amplifier).
The RF driver inputs are from the Drive Splitter, and the outputs
go to RF Driver Combiner, consisting of T7, T10 and T11. T9 is
part of the feed-forward neutralizing circuit, which is described
in the paragraphs on “Neutralization” below.
D.2.7.1 Driver, Section 1
The output of RF driver section 1A and 1B (module 1) is
adjustable, by varying the supply voltage to each half-quad. This
output level is adjusted with “open loop adjust” or “closed loop
adjust” controls on Driver Supply Regulator A22, to obtain the
proper RF drive level to the power amplifier section. The “closed
loop adjust” circuit provides an automatic drive level adjustment, to increase drive if PA section modules fail, and to compensate for line voltage fluctuations. Refer to Section E, Driver
Supply Regulator, for a description of these circuits.
D.2.7.2 Driver, Section 2
Driver section 2A and 2B operates from a fixed +115 Vdc
(unregulated) from the transmitter’s high voltage power supply.
D.2.7.3 Driver, Section 3
Driver section 3 operates either as a full-quad, or as two halfquads, depending on whether neutralization is used or not.
Sections 3A and 3B always operate from a fixed +115 Vdc
(unregulated) from the transmitter’s high voltage supply.
03/16/2009
Driver section 3A and 3B operates as a full-quad RF amplifier
when J16’s jumper plugs are in positions 1-4 and 2-3. Also, in
the T5 secondary circuit, J30 will be jumpered from 1-2; J24 will
be jumpered from 1-2 and 3-4; and J25 through J29 will be in
the OUT position.
When J16 is jumpered from 1-2 and 3-4, section 3A operates as
a half-quad, feeding T11 in the driver combiner, and section 3B
provides feedforward neutralization (described in the paragraphs
on “Neutralization,” below).
D.2.8 Driver Outputs, Impedance Matching
An impedance matching network, consisting of an adjustable or
tapped inductor and a frequency-determined capacitor, is connected in series with each combiner transformer primary (T7,
T10, and T11). Refer to the paragraphs on tune-up/frequency
change procedure in Section V, Maintenance, and to the Frequency Determined Components chart for information on capacitor values, coil tap settings, and adjustment procedures.
D.2.8.1 RF Driver Combiner
The driver’s output combiner consists of three ferrite toroids
with primary windings (T7, T10, and T11) and a copper rod
passing through the toroids which acts as secondary windings
connected in series. The output of the combiner goes to the RF
splitter (shown on the DX-10 Overall Schematic, sheet 2).
The combiner adds RF voltages from the driver sections. The
driver sections do not necessarily deliver the same RF output.
Section 1 output depends on regulated supply voltage, and
section 3 output depends on whether a half-quad or full-quad is
used (whether neutralization is used or not). The voltage ratio of
each of the three toroidal transformers is adjustable in coarse
steps, using J17 through J22 to select taps on their tapped primary
windings.
CAUTION
ALL THREE RF DRIVER MODULES MUST BE IN PLACE WHEN
THE TRANSMITTER IS OPERATED, EVEN IF A MODULE HAS
SHORTED TRANSISTORS. FAILURE TO OBSERVE THIS PRECAUTION COULD RESULT IN OVERHEATING AND CRACKING OF
FERRITE TOROIDS IN T7, T9, T10 OR T11.
D.2.9 Current Sample Transformer T8
The feed-forward neutralization transformer T9 and current
sample transformer T8 are part of the DX-10’s PA Output
Combiner. The section of the copper rod BELOW the ground
point is part of the PA Output Combiner, and the section ABOVE
the ground connection is part of the Driver Combiner.
T8 provides an output combiner current sample, for the Bandpass Filter VSWR circuits on Output Monitor board A27. Refer
to Section H, Output Sample Board/Output Monitor, for additional information.
D.2.10 Neutralization
Neutralization is not required in the DX-10 for normal AM
operation. For optimum AM Stereo performance, however, neutralization is provided to minimize incidental phase modulation
888-2247-006
WARNING: Disconnect primary power prior to servicing.
D-3
(IPM) or incidental quadrature modulation (IQM). Neutralization adjustments must be made while measuring IPM or IQM.
D.4 Adjustments
Neutralization in the DX-10, when used, is FEED-FORWARD
neutralization. An out-of-phase signal is added to the RF output,
in the output combiner, to compensate for drive signal feeding
through the PA stage.
D.4.1 Switch A14S1
This switch selects either section A or section B on the predriver, and is used if failure of one section occurs.
When neutralization is required, J16 must be jumpered from 1-2
and 3-4. This returns combiner transformer T11 to ground (halfquad section 3A then feeds T11), and connects the RF output of
half-quad 3B to feedforward neutralization transformer T9 (at
the “ground” end of the power amplifier output combiner).
Neutralization adjustments are made with jumper plugs at J23
through J30. Refer to the paragraphs on tune-up/frequency
change procedure in Section V, Maintenance, for procedures for
adjusting neutralization.
D.3 Maintenance
This section includes specific maintenance procedures for this
printed circuit board. Refer to Section 5, Maintenance, in this
Technical Manual for general maintenance procedures.
D.3.1 Connectors and Printed Circuit Board Con-
nectors
D.4.2 Other Adjustments
All other adjustments in the RF Driver section are part of the
transmitter tune-up/frequency change procedure. Refer to Section V, Maintenance, in this Technical Manual for tuning procedures.
D.5 Troubleshooting
Troubleshooting for individual modules is not described in this
section. Refer to Section B, Buffer Amplifier, and to Section C,
RF Amplifier Modules, for information on troubleshooting those
modules.
There are no active devices on the RF Driver Combiner/Motherboard. Visual inspection, checking that connectors are properly inserted and component checks are appropriate if problems
are suspected. Resistor measurements and diode checks can be
made without removing components, if modules and plugs are
disconnected to remove possible parallel resistance paths.
Inspect connectors visually, looking for mechanical damage and
signs of overheating or arcing at connector contacts.
Printed circuit board edge connectors, J6 through J10, are not
field replaceable. These are special press-fit connectors, and
attempting to remove them will damage the printed circuit board.
D.3.2 Combiner Toroids
Visually inspect ferrite toroids in the Driver Combiner, looking
for signs of overheating, or for cracked toroids.
D.3.3 Driver Tuning Components
Visually inspect for shorted turns, signs of arcing, or loose
jumper plugs on L1, L2 and L3. Visually inspect C12, C13, and
C14 for any evidence of arcing.
D-4
D.6 Replaceable Parts Service
Replacement parts are available 24 hours a day, seven days a
week from the HARRIS Service Parts Department. Telephone
1-217-222-8200 to contact the service parts department or address correspondence to Service Parts Department, HARRIS
CORPORATION, Broadcast Division, P.O. Box 4290, Quincy,
Illinois 62305-4290, USA. The HARRIS factory may also be
contacted through a TELEX service (247319).
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section E
Driver Supply Regulator (A22)
E.1 Introduction
This section includes a description of the Driver Supply Regulator, and troubleshooting information.
E.4.1 +15 Volt Regulator
A 3-terminal integrated circuit voltage regulator, U1, provides
the +15 Volt supply for U2.
The Driver Supply Regulator assembly includes a printed circuit
board and a heat sink. The printed circuit board is mounted to
the heat sink with spacers. Power MOSFETs in the regulator
circuit are also mounted on the heat sink.
E.4.2 Control +VDC Reference
A CONTROL +VDC voltage is developed for the regulator
section from the Open Loop Adjust control (through a voltage
follower), or from the output of a differential amplifier with
inputs from the Closed Loop Adjust control and from the rf drive
sample. Switch S1 selects one of these reference voltages.
E.2 Location
E.4.2.1 “Open Loop” Reference Voltage
The Driver Supply Regulator is located in the interlocked power
supply compartment, below the RF Multimeter (on the left side
of the compartment as viewed from the front of the transmitter).
When S1 is in the “OPEN LOOP” position, OPEN LOOP ADJUST
control R2 is the input to a voltage follower (gain = 1), using one
section of operational amplifier U2. The voltage follower output
provides a reference voltage, adjustable from about +1.5 Volts to
+10 Volts, to the Q2 gate circuit. See Figure E-1.
E.4.2.2 “Closed Loop” Reference Voltage
E.3 Principles of Operation
The rf drive to the transmitter’s Power Amplifier stage must be
closely controlled for optimum transmitter performance. An rf
drive “automatic level control” loop maintains drive level automatically by monitoring a sample of the rf drive level to the
Power Amplifier from RF Drive Splitter A15.
When S1 is in the “CLOSED LOOP” position, the other half of
U2 is used as a differential amplifier. “CLOSED LOOP ADJUST” control R12 provides an adjustable voltage to the inverting input of the differential amplifier. The non-inverting input is
a dc voltage derived from a sample of the rf drive to the Power
Amplifier stage and is offset by resistors R9 and R10.
E.4.2.3 RF Drive Sample
RF drive levels to the Power Amplifier stage can change, even
if the Driver output remains the same. If MOSFETs on the Power
Amplifier Modules fail the load on the Driver will increase,
causing drive level to decrease. The Driver output must then be
increased to compensate for the additional load. The Driver
Supply Regulator also compensates for rf drive changes caused
by ac line voltage variation.
The rf drive sample for closed-loop operation is taken from the
RF Drive Splitter A15, and fed to the primary winding on
toroidal rf transformer T1. A network across the primary of T1
broad-bands the transformer. Capacitors C4 and C5, across the
secondary windings, are used to provide a load impedance for
the RF Drive Splitter that is similar to the input impedance of an
rf amplifier module.
The Driver Supply Regulator controls and regulates two supply
voltages to rf amplifier D1. Increasing the voltages to D1A and
D1B will increase the Driver output. The regulator’s two dc
outputs can each vary from zero to about +110 Vdc.
The rf drive sample is rectified in a full-wave bridge rectifier
(CR1 through CR4). The output of the bridge rectifier is a dc
voltage sample of the Power Amplifier stage rf drive level. This
dc sample is offset by resistors R10 and R9, filtered by C6 and
fed into U2-3.
During normal operation D1A voltage will be between +40 to
+80 Vdc, and section D1B voltage will be zero. If Driver output
begins to decrease, the Driver Supply Regulator will increase the
voltage to D1A until it reaches about +100 to +110 Vdc. If more
rf drive is required, the Driver Supply Regulator will increase
the voltage to D1B until it reaches about +100 to +110 Vdc.
Refer to SECTION V, Maintenance, for adjustment and maintenance procedures.
E.4 Circuit Description
Refer to Simplified Diagram E-1 and to Schematic 839-6208227 in the Drawing Package.
03/16/2009
The other input to U2-2 is an adjustable dc voltage from Closed
Loop ADJ R12. The output of U2-1 is the difference between
the inputs times the gain of the amplifier. Differential amplifier
gain is set by R11, R12, R13, R14, and R15.
The output of U2-1 is the CONTROL +VDC voltage and can be
monitored on the RF MULTIMETER on the inside of the noninterlocked Compartment door.
E.4.3 Power MOSFET Operation (A Short Review)
Power MOSFET operation will be reviewed briefly in this
paragraph, for personnel who have not encountered them before.
The n-channel power MOSFETs used in the Driver Supply
Regulator section are effectively “cut off” (not conducting)
when their input voltage is less than the +2 to +4 Volt gate-tosource threshold. As the input voltage rises above the threshold,
the MOSFET will conduct more heavily. Increasing the gate
888-2247-006
WARNING: Disconnect primary power prior to servicing.
E-1
voltage will increase the drain current and decrease the effective
source-to-drain “resistance.” An input voltage of less than +10
Volts will effectively “saturate” the MOSFETs in this circuit and
result in minimum source-to-drain resistance.
E.4.4 Regulator Section Circuit Description
The regulator section includes an input amplifier stage Q2 and
series regulator pass transistors for the two regulated outputs.
Parallel pass transistors Q3 and Q4 are used for the Section D1A
output voltage, and Q5 and Q6 are used for the Section D1B
output voltage.
Each series pass transistor section can also be thought of as a
source follower circuit, with D1 as the load. The regulator output
voltage will be 2 to 10 Volts less positive than the gate voltage.
The gate voltage of Q3-Q4 will be determined by Q2 drain
voltage and the voltage divider; the gate voltage of Q5-Q6 will
be determined by Q2 drain voltage and the voltage offset circuit.
E.4.5 DC Amplifier Stage (Q2)
The reference voltage from U2-1 is fed through R16 to a current
summing network at the gate of Q2. The inputs to the summing
network include R19, Q2 stage negative feedback, R41, negative
feedback from regulator section A output, and R42, negative
feedback from regulator section B output. The output of the
summing network is offset 1.4 Volts by diodes CR5 and CR6.
The sum of the four currents creates a voltage drop across R20
which is the gate voltage for Q2. Capacitor C8 bypasses ac
components around the voltage offset diodes to speed up regulator response time.
N-channel power MOSFET Q2 is used as a dc amplifier, with its
drain connected to the +230 Vdc supply through load resistors
R25 and R26 on Fuse Board A24. The MOSFET begins conducting when its gate voltage goes above a +2 to +4 Volt threshold.
Once the threshold is exceeded, the MOSFET’s drain current
will increase as the gate goes more positive and the drain voltage
will decrease because of the voltage drop across load resistors
R25 and R26 on Fuse Board A24. The output of the Q2 amplifier
stage is coupled to Q3-Q4 gates through a resistive voltage
divider, and to Q5-Q6 gates through zener diodes CR7, CR9, and
CR10.
E.4.6 Series Pass Transistors Q3 and Q4 (For Sec-
tion D1A Supply Voltage)
The regulated output voltage to driver section D1A is controlled
by series pass transistors Q3 and Q4. When their gate voltage is
zero, they are cut off and the section D1A output voltage is zero.
Q3 and Q4 begin conducting (turning on) when their gate voltage
is a few Volts positive (+2 to +4 Volts relative to their source).
As the gate voltage becomes more positive, they conduct more
heavily, and the section D1A output voltage increases.
E.4.6.1 Voltage Divider
The voltage drop across resistor R25 is the gate voltage for Q3
and Q4; R25 is part of a voltage divider between Q2 drain and
Q3-Q4 source. The voltage DIFFERENCE between Q2’s drain
voltage and regulator output voltage “A” is divided by the
voltage divider consisting of R22, R24, and R25. As Q2 drain
E-2
becomes more positive, voltage across R25 increases, Q3-Q4
conduct more, and the section D1A output voltage increases.
Capacitor C9 and R23-C10 provide a low impedance path
around R22 and R24 for ac components. Their effect is to speed
up response to sudden variations in output; this action will also
reduce ac ripple in the regulated output voltage.
Resistors R58, R59, and R64 in the source circuit are current
equalizing resistors which compensate for variations in characteristics of the paralleled MOSFETs. Ten Volt zener diodes CR8,
CR12, and CR16 protect the MOSFETs against excessive
source-to-gate voltage.
Diode CR13 at the regulator output protects the circuit against
negative transient voltages.
Resistor R41 provides negative feedback for the regulator section.
E.4.7 Series Pass Transistors Q5 and Q6 (For Sec-
tion D1B Supply Voltage)
The regulated output voltage to driver section D1B is controlled
by series pass transistors Q5 and Q6. Except for the zener voltage
offset diodes, this section operates in the same way as pass
transistors Q3-Q4.
E.4.7.1 Voltage Offset
The voltage across resistor R34 is the gate voltage for Q5 and
Q6. Resistors R34, R33, and zener diodes CR7, CR9, and CR10
are all in series, between Q5-Q6 source and Q2 drain. The zener
diodes will not conduct until the voltage at the drain of Q2
exceeds the 133 Volt sum of the zener voltages. Until the zener
diodes conduct there will be no voltage drop across R34 and Q5
and Q6 remain cut off.
When the voltage at the drain of Q2 is high enough to overcome
the zener voltage, Q5 and Q6 begin to turn on. At this point, Q3,
Q4, and Q7 are conducting heavily so that output voltage “A” is
nearly at the +115 Vdc input. As the voltage at the drain of Q2
becomes still more positive, Q5 and Q6 turn on more, causing
output voltage “B” to increase while output voltage “A” remains
at maximum.
Transistor Q1 is used to ensure that Q5 and Q6 can turn on fully,
so that the supply voltage to driver Section D1B can approach
the +115 Vdc input when required. The base-emitter voltage for
Q1 is the voltage drop across R22, which is part of the voltage
divider that controls Q3 and Q4. When Q3 and Q4 are nearly
saturated, Q1 will begin turning on so that the voltage across Q1
and CR7 will be less than 39 Volts and the zener offset will be
less than 133 Volts.
Capacitor C11, and R32-C12 provide low impedance paths
around the zener diodes for ac components. Their effect is to
speed up response to sudden variations in output; they also
reduce ac ripple in the regulated output voltage.
Resistors R60, R61, and R65 are current equalizing resistors.
Resistors R35, R36, and R63, in the gate circuits, are parasitic
suppressers. Ten Volt zener diodes CR11, CR14, and CR17
protect the MOSFETs against excessive source-to-gate voltage.
Diode CR15 protects the regulator circuit against negative transient voltages.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure E-1
Driver Supply Regulator simplified schematic diagram.
Resistor R42 provides negative feedback around the regulator
section.
E.5 Troubleshooting The Driver Supply
E.4.8 Metering Circuits
RF Driver voltages and currents are metered on the RF MULTIMETER.
Troubleshooting the Driver Supply Regulator can be done by
first checking for proper operation of the regulator, then, if the
fault is determined to be in the regulator assembly, removing the
assembly and making out-of-circuit measurements to locate the
fault.
E.4.8.1 Reference Voltage (CONTROL +VDC)
The rf level reference voltage outputs from U2A or U2B are
metered in the “CONTROL +VDC” position. R4 is the meter
multiplier resistor. The CONTROL +VDC voltage is also sent
to the Driver Encoder/Temp Sense Board through R5.
E.4.8.2 115 Vdc PA Supply Voltage (DRIVER +VDC)
The +115 Vdc supply voltage is metered in the DRIVER +VDC
position. The +115 Vdc is sampled at the supply side of R3 and
enters the Driver Supply Regulator at J2. Resistors R46, R47, R48,
and R49 form the meter multiplier circuit used in this position.
E.4.8.3 Driver Current Metering (“DRIVER IDC”)
The “DRIVER IDC” position of the RF Multimeter reads total
Driver current. All Driver current passes through the three 0.1
Ohm resistors R3A, R3B, and R3C, and the voltage drop across
the resistor is measured. Resistors R44 and R45 are voltmeter
multiplier resistors.
Regulator
Because the operation of the Driver Supply Regulator is dependent on the overall drive from the Driver Stage, the voltage
readings of D1A and D1B can change under various conditions.
If the ac line voltage changes, the dc voltage to the Driver
Modules will change and the Driver Supply Regulator will vary
the voltage to D1A and D1B to compensate.
If the dc supply goes DOWN, the Driver Supply Regulator will
INCREASE the voltage to D1A and D1B.
If the dc supply goes UP, the Driver Supply Regulator will
DECREASE the voltage to D1A and D1B.
Proper operation of the Driver Supply Regulator can be determined by changing the overall drive level and noting the operation of the regulator circuit.
E.4.8.4 Driver Amplifier D1 Voltages (DRIVER 1A +VDC)
and (DRIVER 1B +VDC)
E.5.1 Symptom: Driver Sect D1A +VDC and Sect
The Driver Supply Regulator output voltages feeding D1A and
D1B are metered in these two positions. R54, R55, R56, and R57
are the “A” circuit meter multiplier resistors while R50, R51,
R52, and R53 form the “B” circuit.
E.5.1.1 Possible Cause: No +15 VDC
03/16/2009
D1B +VDC Both High
Check the Regulator +15 VDC position on the RF MULTIMETER. This voltage should be present any time primary power is
applied to the transmitter, even if the transmitter is “OFF.” If this
voltage is zero (or very low), possible causes include no +22 Vdc
888-2247-006
WARNING: Disconnect primary power prior to servicing.
E-3
input or defective U1e. Check for +22 Vdc on the front panel
multimeter; check connector to J2 on the Driver Supply Regulator. To check U1 operation, you can remove the Driver Supply
Regulator assembly and check on the bench with an input of +22
Vdc at J2-1.
E.5.1.2 Possible Cause: Defective U2
If U2 output remains LOW, both Driver Supply Regulator output
voltages will be high. Check U2 operation by removing the
Driver Supply Regulator assembly, and checking on the bench
by applying an input of about +22 Volts at J2-1. When OPEN
LOOP ADJUST control R2 is adjusted over its range, U2 output
should vary from about +1.5 to +10 Volts.
E.5.1.3 Possible Cause: Defective S1
If the Gate Voltage at Q2 remains low (no input voltage from
S1), both Driver Supply Regulator outputs will remain high.
Refer to the “bench check” under “Defective U2,” above.
E.5.2 Symptom: One Output Voltage Is +100 To
+110 Volts, Other Can Be Adjusted.
E.5.2.1 Possible Cause: Shorted MOSFET in a series regulator section (Q3, Q4, Q5 and Q6)
Remove the regulator assembly and check MOSFETs. If a
MOSFET is shorted, its gate-to-source zener diode should also
be checked as a precaution.
E.5.3 Symptom: Both Driver Supply Regulator Out-
E.5.4 Symptom: One Driver Supply Output Voltage
is Zero, the Other Can Be Adjusted.
E.5.4.1 Possible Cause: Shorted Gate-to-Source Zener Diode
(CR8, CR11, CR12 and CR14)
Use an Ohmmeter to check the zener diodes in the faulty section
(Q3-Q4) circuit or Q5-Q6 circuit). You should read a high
resistance in one direction and a low resistance in the other
direction. One shorted zener diode will cause both MOSFETs to
remain cut off, so that output voltage for that section is zero.
E.5.5 Symptom: Section D1B Voltage Increases Be-
fore Section D1A Voltage Reaches +100 Volts.
E.5.5.1 Possible Causes: Voltage Offset is Too Low
A low offset voltage in the regulator section could be caused by
a leaky or shorted transistor Q1, or a zener diode that is shorted
or is conducting at a low voltage. Remove all primary power
from the transmitter, remove the driver regulator assembly from
the transmitter, and check these components.
E.5.6 Symptom: Open Loop Operation is Correct,
Closed Loop Operation is Faulty.
E.5.6.1 Possible Cause: No RF Sample Voltage
put Voltages Are Zero.
E.5.3.1 Possible Cause: No +115 Vdc
Remove all primary power and check F10 on Fuse Board A24
in the high voltage power supply compartment. If F10 is open,
check for possible short circuits to ground in the +115 Vdc
supply components, cabling, and on the Driver Supply Regulator. If F10 is good, check for loose connector or other open circuit
between the +115 Vdc supply output and the Driver Supply
Regulator.
E.5.3.2 Possible Cause: Driver Supply Regulator component
The fault is probably in the Driver Supply Regulator, and could
be any of the following:
a. Defective U2. If the input to Q2 remains HIGH, both
Driver Supply Regulator output voltages will remain
LOW. Check U2 operation by removing the Driver Supply
Regulator assembly, and checking on the bench by applying an input of about +22 Volts at J2-1. When OPEN
LOOP ADJUST control R2 is adjusted over its range, U2
output should vary from about +1.5 to +10 Volts.
E-4
b. Shorted Q2. Check Q2, using the out-of-circuit MOSFET
Ohmmeter check in Section 5, Maintenance (The Ohmmeter check used for bipolar transistors will NOT check
MOSFETs).
If there is no rf sample voltage, Driver Supply Regulator output
voltages will be high, because the regulator will attempt to
increase Driver output. Adjusting CLOSED LOOP ADJUST
control (R12) to minimum may reduce Driver output. Check the
coaxial cable and connectors between RF Drive Splitter A15 and
Driver Supply Regulator A22 for continuity.
E.5.6.2 Possible Cause: Shorted Diode in Bridge Rectifier
CR1-CR4
Check bridge rectifier diodes CR1 through CR4 for shorted
diodes (the diodes in this bridge can be checked in-circuit, using
an Ohmmeter).
E.5.6.3 Possible Cause: Defective U2
Operation of U2 can be checked with the Driver Supply Regulator assembly on the bench, using a +22 Vdc dc supply at J2-1.
The voltage at U2-1 should vary when CLOSED LOOP ADJUST Control R12 is varied over its range.
NOTE
If the setting of R12 is changed, refer to the section on setting rf
drive in the Tuning/Frequency Change Procedure in SECTION
V, Maintenance, for proper adjustment of rf drive.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section F
RF Multimeter (A23)
F.1 Introduction
This section describes the RF Multimeter board.
The RF Multimeter provides metering of the Predriver and
Driver sections of the transmitter. A probe, with four meter
positions, is also provided for ac and dc voltage measurements
on printed circuit boards in the transmitter’s non-interlocked
compartment. The RF Multimeter is located on the back of the
Driver Compartment door. The probe is located in the Center
Control Compartment.
Refer to SECTION V, Maintenance, for pc board maintenance
procedures. There are no adjustments on this board.
F.2 Circuit Description
Refer to the RF Multimeter Schematic, 839-6208-302, in the
Drawing Package.
The meter has a 100 microampere movement, and two scales,
0-3 and 0-10. The meter switch positions are labeled with the
name of the metered function and the scale used. For some
positions, a X10 or X100 multiplier is applied to the meter scale
reading.
Meter M1 is protected against excessive voltages and currents
by 1-amp rectifier diodes CR4 and CR5. Capacitor C3 provides
RF bypassing around the meter movement.
F.2.1 Metering Driver Section Parameters
For 0-3 Volt, 0-30 Volt, and 0-300 Volt dc ranges, the multimeter
is a 10,000 Ohm per Volt meter. For current ranges, the meter
acts as a voltmeter, measuring the voltage drop across a resistor
in the dc current path. One side of the meter is grounded through
a section of switch S1 for Driver stage voltage measurements.
The meter is isolated from ground for current measurements.
03/16/2009
For Predriver voltage measurements, series multiplier resistors
are located on the Driver Combiner/Motherboard, A14. For
Driver voltages, voltmeter multiplier resistors are located on the
Driver Supply Regulator, A22. The shunt resistor for “Predriver
IDC” current measurements is located on the Driver Combiner/Motherboard, A14, and the shunt resistor for “Driver IDC”
is located on the Driver Supply Regulator, A22. Refer to Section
D, Driver Combiner/Motherboard and Section E, Driver Supply
Regulator for descriptions of those metering circuits.
PREDRIVER
PREDRIVER
CONTROL
DRIVER
DRIVER
DRIVER 1A
DRIVER 1B
IDC
+VDC
+VDC
+VDC
IDC
+VDC
+VDC
SECT. D
SECT. D
SECT. E
SECT. E
SECT. E
SECT. E
SECT. E.
F.2.2 Multimeter Probe
The multimeter uses a flexible coiled patch cord with a clip-on
probe for convenient measurement of voltages in the non-interlocked compartment. Measurement ranges available are 0 to 30
Peak AC Volts, 0 to +3 VDC, 0 to +30 VDC, and 0 to -30 VDC.
Resistor R5, 29.4K 1%, is the multiplier resistor for the 0-3 Volt
range. The total 30K resistance required for this range includes
the meter resistance.
Resistor R3, a 301K 1% resistor, is the multiplier resistor for the
0-30 Volt range. Positive and negative voltage ranges are obtained by grounding either the negative or positive meter terminal through S1.
For AC Voltage measurements, CR1, R4, C1 and R1 make up a
peak detector. Resistor R2 is the multiplier resistor for the ac
voltage range.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
F-1
F-2
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section G
RF Combiners:
Binary Combiner/Motherboard (A18)
and Main Combiner/Motherboards (A19, A20)
G.1 Introduction
This section describes the printed circuit RF combiner/motherboards and the RF combiner.
The DX-10 uses one Binary Combiner/Motherboard and two
Main Combiner/Motherboards. The three Combiner/Motherboards are mounted in the rear center compartment.
RF Power Amplifier modules plug into sockets on the combiner/motherboards. Each board includes sockets for 16 of the
48 RF power amplifier modules (modules A44 through A91).
For each module, there is a ferrite toroid core with an RF
transformer primary winding. The secondary of each of these
toroidal transformers (T1 through T16) is the large copper “combiner pipe,” which passes vertically through all 48 toroids on
these three boards, so that the 48 transformers on the three boards
make up the RF power combiner. The toroids are mounted on
the combiner/motherboards, and are enclosed in a shield. Tapped
air-core coils (L1 through L16) are also mounted on the back
side of the boards.
G.2 Principles of Operation
Refer to the Main Combiner/Motherboard schematic diagram
839-6208-229 and Binary Combiner/Motherboard schematic
diagram 839-6208-268 for the following description. RF Amplifier Modules are described in Section C.
For a description of power amplifier operation in a digital
modulation system, refer to the System Operation section. This
section will describe only combiner operation and components
mounted on the combiner/motherboards.
G.2.1 RF Power Combiner
The RF Power Combiner consists of a heavy copper rod which
passes vertically through 48 ferrite toroids on the combiner/motherboards. Each toroid has a winding which is a transformer primary winding; the copper rod is the secondary for all
48 combiner transformers. All primary windings in the main
combiners have the same number of turns.
The combiner secondary (copper rod) is made in sections, which
are bolted together, to facilitate removing any combiner/motherboard if necessary.
The copper rod is grounded near the top. The section above the
ground point is the driver combiner secondary and passes
through three driver combiner toroids. Refer to Section D, Driver
Combiner/Motherboard for a description of the driver section.
Each RF amplifier module induces an RF voltage in the combiner’s secondary “winding” (rod). The RF voltages from all RF
amplifiers which are turned “ON” add in the secondary (the
03/16/2009
copper rod). The total Power Amplifier output appears at the
bottom of the combiner, at a 4 ohm impedance point. At the
DX-10’s nominal 10 kW power, RF current in the combiner
secondary (pipe) is 75 amperes, and the large copper rod used
for the secondary is required to keep IR losses low.
The RF power delivered by each RF amplifier module is NOT
constant. When a small number of modules are “ON,” each
module delivers a small amount of power. When a large number
of modules are “ON,” each module delivers a much larger
amount of power. Also, because the modules are effectively
connected in series, by the series connected transformers, the
same current flows in all modules. This is true whether a module
is in the “on” or the “off” state.
CAUTION
DO NOT OPERATE THE DX-10 UNLESS ALL PA MODULES ARE
INSTALLED, EVEN IF SOME MODULES HAVE SHORTED TRANSISTORS. EACH TOROIDAL TRANSFORMER PRIMARY WINDING
MUST HAVE AN RF CURRENT PATH ACROSS IT, OR MUST BE
SUPPLYING POWER TO THE COMBINER. FAILURE TO OBSERVE
THIS PRECAUTION COULD RESULT IN ARCING TO THE FERRITE TOROID CORES, AND COULD RESULT IN CRACKED CORES.
G.2.2 Combiner Output Steps
In the RF combiners in the DX-10, it is not necessary to have all
modules delivering the same power. At any instant in time, some
of the modules will be “OFF” (except at a very high positive
modulation peak, when all modules will be ON). Also, RF
amplifier modules used as Binary Steps will deliver less power
than those used as “Full Steps.” Don’t think of power output from
each RF amplifier module! In the DX-10 power amplifier, module output VOLTAGES add to produce a total voltage, and, at
any instant, the RF voltage observed on an oscilloscope (or
producing an instantaneous reading on a modulation monitor) is
just the sum of the incremental voltages from the contributing
modules. The current at that instant is this total voltage divided
by the combiner load impedance (approximately 4 ohms).
It is very important to remember that as additional amplifiers are
turned on, the combiner output steps are equal VOLTAGE steps
(not equal power steps). At 10 kilowatts carrier power, the
combiner output current is nominally 75 amperes. At a 100%
positive modulation peak, this current will be two times 75
amperes, or 150 amperes (and the RF voltage at the output will
also double). (The instantaneous power at this 100% peak will
be 40 kilowatts). If 20 modules are “ON” at carrier power (10
kW), twice this number, or 40 modules will be “ON” at a 100%
positive modulation peak, to provide twice the VOLTAGE (and
RF output voltage). Refer to the review of Amplitude Modulation and Digital Modulation in the System Operation section, for
more information.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
G-1
G.2.3 Main Combiner/Motherboards (A19, A20)
Each Main Combiner/Motherboard contains combiner transformer toroids (T1 through T16 on each board) and a printed
circuit board socket for 16 RF amplifier modules. A tapped
“efficiency inductor,” which is an air-core coil, is paralleled with
each transformer winding. Tap positions depend on operating
frequency, and are listed in the frequency determined components chart in this Technical Manual. A copper rod section passes
through the toroids, forming a section of the combiner secondary
“winding.” Sections of the copper rod are joined with recessedhead 1/4-28 stainless steel bolts; one of the sections is threaded
to accept the bolts so that nuts and washers are not used.
with P30, P31, P32, and P33. Tap positions are shown in the
Frequency Determined Components chart.
The motherboard also contains connectors for DC supply voltage (B+), connectors for RF drive inputs, and connectors for
encoded audio inputs from the modulation encoder board.
The Main Combiner board includes RC filtering in the DC
supply buses. The Binary Combiner Motherboard includes an
RC swamping circuit, involving the 6 Binary Steps and Big Steps
1, 2, 5 and 6. The swamping resistor and capacitor are mounted
external to the board, and their values are frequency dependent
and are listed in the Frequency Determined Components chart.
G.2.3.1 DC Supply
On the Main Combiner boards, all modules operate from a +230
volt unregulated voltage from the transmitter’s high voltage
supply.
G.2.4.2 DC Supply Voltages
On the Binary combiner board, four modules are operated from
+115 volts dc, from the high voltage power supply, and two
additional modules are operated from +30 volts dc, from the low
voltage power supply. The remaining 10 modules on the board
are “Big Steps” and operate from the +230 volt supply. The
following steps operate from +115 volts dc: 1/2, 1/4, 1/8 and 1/16
step. As the steps become smaller, there are more turns in their
combiner transformer primary windings. The 1/32 and 1/64 steps
operate from +30 volts dc.
G.2.3.2 RF Drive
RF drive inputs come from RF Drive Splitter A15. There is a
separate RF drive cable for each half-quad, so that there are two
separate RF drive cables for each amplifier module. All RF drive
coaxial cables are the same length, so that all RF drive signals
are in phase.
G.2.3.3 Encoded Audio (Module ON/OFF Control Signals)
The encoded audio inputs are the control signals for the amplifier
modules. These encoded digital signals turn on the number of
modules needed for the RF output at each instant in time.
G.2.4 Binary Combiner/Motherboard (A18)
The binary combiner-motherboard is similar to the main combiner/motherboard, with some additional components and differences.
On the Main Combiner/Motherboard, all active amplifiers deliver the same power. On the binary combiner/motherboard,
however, there are fractional steps, as described in the next
paragraphs and in the discussion of Digital Modulation in the
System Operation section.
G.2.4.1 Binary Steps
As already discussed in the Digital Modulation description in
Section 4, there are 42 equal “Big Steps” and 6 Binary Steps.
The Binary steps include 1/2 step, 1/4 step, 1/8 step, 1/16 step,
1/32 step, and 1/64 step. (Recall that these are RF voltage, NOT
power steps). The RF amplifier modules used in binary step
positions are identical to all other RF amplifier modules, and are
interchangeable. The differences in binary steps are all on the
Binary Combiner/Motherboard.
The fractional BINARY STEPS are obtained by operating binary amplifier modules at reduced supply voltages, and also by
employing different numbers of turns on the combiner transformer windings for these modules. Four of the Binary steps (1/2,
1/4, 1/8, and 1/16) employ tapped transformer primary windings.
The tap positions depend on operating frequency and are selected
G-2
G.3 Maintenance
The only adjustments on the Combiner/Motherboards are the
tapped inductors, L1 through L16, on each board. Tap positions
depend on frequency, and are included in the Frequency Determined Components chart.
G.3.1 Replacing Components
The printed circuit board, edge connector sockets used on the
Combiner Boards are not replaceable. These are special press-fit
sockets, which cannot be removed without damaging the printed
circuit board. Socket failure is not likely, just as damage to
printed circuit board traces is possible but not likely.
G.4 Troubleshooting
Troubleshooting on the combiner/motherboards consists essentially of visual inspection. Possible problem areas include:
a. Damage to printed circuit traces.
b. Connectors loose. Physically check connectors; plugs
should be properly inserted into jacks or sockets.
c. Connector damage. Inspect connectors carefully, including removing amplifier modules if necessary to inspect pc
board edge connectors.
d. Cracked ferrite toroid cores. The shield over the combiner
must be removed to check combiner transformer cores. (If
transformers must be replaced, be certain that the replacement has the same number of turns of wire as the original).
e. Loose taps, or incorrectly set taps on air-core inductors L1
through L16. Check tap positions against the frequencydetermined components chart, if required.
f. Loose connections where combiner rod sections join.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
g. Failed electrolytic capacitors, used in the RC filtering in
supply voltage lines on each board.
03/16/2009
G.5 Controls and Indicators
The combiner/motherboards have no controls. The only adjustments available are coil tap positions. The inductors are labeled
on the boards, so this section will not include a “Controls and
Indicators” table.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
G-3
G-4
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section H
Output Sample Board (A26) and
Output Monitor (A27)
H.1 Introduction
This section includes circuit descriptions and troubleshooting
information for the Output Sample Board and Output Monitor.
The Output Sample Board contains circuits to sample RF voltage
and RF current. The outputs of these sample circuits are fed to
the Output Monitor. The Output Sample Board is located in the
Output Network Compartment.
The Output Monitor includes circuits for VSWR protection,
power metering, and modulation monitoring. The Output Monitor is located on the upper left side of the Center Control
Compartment.
H.2 Circuit Description
Refer to SECTION V, Maintenance, for adjustment procedures
and pc board maintenance procedures.
H.2.1 Output Sample Board
The Output Sample Board contains RF voltage samples and RF
current samples from the 50 Ohm point in the output network.
These are sent to the Output Monitor for VSWR protection and
Forward/Reflected power monitoring.
H.2.1.1 Current Samples
The RF output conductor passes through toroidal transformers
T1 and T2. These transformers pick up samples of RF current.
• A voltage proportional to the current through T1 is devel-
oped across resistors R1 and R2 for the Antenna VSWR
circuit and sent to the Output Monitor at J1-1.
• Voltages proportional to the current through T2 are developed across resistors R3 through R6 for forward/reflected
current samples to the directional coupler. The forward
sample is sent to the Output Monitor at J1-3 and the
reflected sample is sent to the Output Monitor at J1-5.
These voltages are 180° out of phase.
H.2.1.2 Voltage Samples
• Capacitive voltage divider C7/C8 develops a voltage sam-
ple for the forward power directional coupler. This sample
is sent to the Output Monitor at J1-17.
• Capacitive voltage divider C5/C6 develops a voltage sample for the reflected power directional coupler. This sample
is sent to the Output Monitor at J1-15.
• Capacitive voltage divider C3/C4 develops a voltage sample for the Antenna VSWR circuit at J1-11.
• Capacitive voltage divider C1/C2 develops a voltage sample for the Netwrok VSWR circuit at J1-9.
H.2.2 Output Monitor
The Output Monitor contains circuits to detect a VSWR condition when arcs, faults, or impedance changes occur in the transmitter bandpass filter/output network or in the antenna system
or load connected to the transmitter output. If a VSWR fault is
03/16/2009
detected, the PA modules are immediately turned off and the
“Oscillator Sync” circuit is activated. This will protect the PA
module transistors during a VSWR shut-down. The VSWR logic
on the LED Board will return the transmitter to normal operation
within approximately 20 milliseconds unless a number of
VSWR trips occur in quick succession.
Directional Coupler circuits to detect Forward/Reflected power
and Modulation Monitor sample adjustment circuits are also on
this board.
H.2.2.1 Phase Angle Detector, Theory Of Operation
This description of Phase Angle Detector circuit operation applies to both the Antenna VSWR and Bandpass Filter VSWR
phase angle detectors. Refer to the Simplified Schematic Diagram (Phase Angle Detectors), Figure H-1, for the following
discussion.
When a transmission line is terminated with a resistive load, the
VSWR will be 1.0 and voltage and current in the line will be in
phase and will have amplitudes determined by Ohm’s law
(E=IR). If the load RESISTANCE changes, the current and
voltage AMPLITUDE relationship will change. If the load REACTANCE changes, the current and voltage PHASE relationship will change. The phase angle detectors used in the
transmitter are balanced or “nulled” for the phase and amplitude
relationships that exist when the output network is properly
tuned into a 50 + j0 Ohms. Any VSWR condition will cause the
RF current and voltage phase/amplitude to change. This will
produce a voltage at the output of one or both phase angle
detectors.
a. CURRENT SAMPLE: The current sample for the phase
angle detector is a current transformer. The primary, a
copper tube or rod carrying the RF current, passes through
the secondary, a ferrite core inductor. Resistors are connected across the secondary to load the winding and to
convert the current sample to a voltage sample for the
phase angle detector.
b. VOLTAGE SAMPLE: A capacitive voltage divider provides an RF voltage sample for the phase angle detector.
The RF voltage sample and the RF current sample are applied to
opposite ends of the primary winding of the phase angle detector
transformer (T1 or T3). When the samples are in phase and have
the same amplitudes, there will be no RF current flow through
the transformer. If the phase and/or amplitude of either sample
changes, current will flow through the transformer primary
winding and a voltage will be induced in the secondary winding.
A full-wave rectifier will then produce a DC output voltage at
the phase angle detector output.
To eliminate any interaction between voltage and current samples, the primary winding is tuned to parallel resonance at the
transmitter’s operating frequency to provide a high impedance
between the samples. Switch-selected capacitors and inductors
888-2247-006
WARNING: Disconnect primary power prior to servicing.
H-1
are used for coarse tuning, and a variable capacitor is used for
fine tuning. The normal/cal switch is provided to resonate the
transformer primary circuit. When the switch is in the “Cal”
position, the current sample is disconnected and the RF voltage
sample will be applied to one end of the transformer primary.
The voltage sample input at J1-9 is fed to amplitude adjustment
C16 and parallel capacitors C20 and C28 selected by S2.
The RF voltage sample (AMPLITUDE) adjustment is a variable
capacitor across the lower half of the capacitive voltage divider.
The RF current (PHASE) adjustment is a capacitor in the parallel
L-C circuit. With the transmitter properly tuned, the detector is
“balanced” by adjusting the RF voltages at opposite ends of the
transformer primary for equal amplitude and phase. When the
detector is balanced, the DC output of the detector should be
zero.
The output of T3 is rectified by CR12 and CR16 and applied to
the inverting input of U2.
H.2.2.2 Antenna VSWR Phase Angle Detector
The Antenna VSWR Phase Angle Detector current sample from
the Output Sample Board enters at J1-1 and is fed to parallel
circuit L12 and C43 through C46. Switch S6 selects the capacitance and L12 is used to adjust the phase.
The Antenna VSWR Phase Angle Detector voltage sample from
the Output Sample Board enters at J1-11 and is fed to amplitude
adjustment C15.
Parallel components C41, C42, L9 and L10, selected by S9, and
capacitor C29 are used to resonate the primary of T1 to the carrier
frequency.
The output signal is rectified by CR7 and CR9 and applied to the
inverting input of U3.
H.2.2.3 Bandpass Filter VSWR Phase Angle Detector
The Bandpass Filter VSWR Phase Angle Detector is also referred to as the “Internal Phase Angle Detector”.
The Bandpass VSWR Phase Angle Detector current sample
from T9 enters the board at J3-6 is fed to parallel resonant circuit
L5 through L8 and C12, C39 and C47. Switch S7 is used to select
coarse values of inductance and capacitance.
Parallel components L2, L3, C3 and C5, selected by S1, and
capacitor C21 are used to resonate the primary of T3 to the carrier
frequency.
H.2.2.4 “Phase Angle Detector Null” Meter Indications
The phase angle detector outputs at TP8 and TP9 are DC voltages
which are sent to the LED Board on J2-23 and J2-25. The signals
pass through the LED Board to the Controller where voltage
follower amplifiers are used to drive the front panel MULTIMETER. The voltages are metered as “DETECTOR NULL (ANTENNA)” and “DETECTOR NULL (FILTER).” These voltages
are also available at the external interface for remote metering.
The “DETECTOR NULL” indications are relative readings. When
phase detectors are properly balanced they should both read zero.
Once the transmitter is tuned, any change in the Bandpass Filter will
cause the DETECTOR NULL (FILTER) reading to increase. The
DETECTOR NULL (ANTENNA) reading will increase if the load
on the transmitter output changes.
H.2.2.5 VSWR Trip Circuits
Because the Antenna VSWR and Bandpass Filter VSWR circuits are identical except for time constants, only the Antenna
VSWR trip circuit will be discussed.
H.2.2.5.1
Comparator
The trip circuit uses an LM-360 differential comparator U3. The
non-inverting input U3-5 is an adjustable positive “reference”
voltage from the ANTENNA VSWR TRIP ADJUST control,
R24. The inverting input U3-4 is the DC signal from the phase
angle detector. Normally, the inverting input U3-4 will be at zero
Volts, and the comparator output U3-11 will go HIGH. If a
VSWR condition occurs, the voltage from the phase angle output
at U3-4 will exceed the “reference” voltage at U3-5 and the
Figure H-1
Phase Angle Detector simplified diagram.
H-2
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
comparator output will go LOW. Diodes CR11 and CR13 protect
U1 from transient voltages.
H.2.2.5.2
R-C Network
A VSWR condition may last for only a few microseconds.
Because the transmitter output is turned off very rapidly by a
logic signal which goes directly to the Modulation Encoder, this
may not be enough time for fault and overload logic to act.
Capacitor-resistor network C14/R38 holds the comparator output low for about 20 microseconds or more after the phase angle
detector output returns to normal.
H.2.2.5.3
Manual VSWR Trip
Manual VSWR Trip switch S4 simulates a VSWR fault by
pulling the phase angle detector output to +5 VDC.
H.2.2.5.4
VSWR Loop Self Test
The transmitter includes a self-test feature. Each time the transmitter low voltage supply is turned on, the VSWR trip circuits
and logic are tested. The result of the “self-test” is indicated by
the VSWR Sensor “STATUS” LED on the ColorStat™ panel.
The LED will pulse red and then turn green if the test is
successful, but will remain red if the test fails.
VSWR self-test logic circuits are described in SECTION Q,
LED Board. The logic generates a Self-Test Logic LOW pulse,
and evaluates the results of the test, whenever any of three
conditions occurs:
a. Transmitter low voltage is applied (either after shut-down
for maintenance or after a power failure).
b. The VSWR Sensor “MANUAL TEST” button on the
ColorStat™ panel is depressed.
c. A remote VSWR “Manual Test” command is given,
through the External Interface.
On the Output Monitor, the logic LOW self-test pulse turns on
transistors Q5 and Q6, pulling the non-inverting inputs of both
VSWR trip comparators to +5 VDC (Logic High) and simulating
a VSWR fault.
H.2.2.6 “VSWR Trip” Logic
The output of U3-11 goes to monostable multivibrator U6-1 and
also to AND gate U5-9.
H.2.2.7 AND Gate U5
If U5-9 or U5-10 goes LOW, U5-8 also goes LOW. This output
goes directly to the Modulation Encoder to immediately turn all
PA modules OFF.
H.2.2.8 Monostable Multivibrators
Each time a VSWR condition is detected by one of the phase angle
detector circuits, dual retriggerable monostable multivibrator U6 is
triggered by the falling (negative going) edge of VSWR trip comparators U2-11 or U3-11. The U6 output LOW pulses go to the
VSWR fault and overload logic on the LED Board.
Section U6-4 is the output to the “Antenna VSWR trip” and
section U6-12 is the output for the “Bandpass Filter VSWR trip.”
The output LOW pulse width for each trip pulse is determined
by a resistor-capacitor network. For the “Antenna VSWR trip”
C48 and R51 at U6-15 set a pulse width of 14 milliseconds. For
03/16/2009
the “Bandpass VSWR trip” C49 and R50 at U6-7 provide a 19
millisecond pulse width.
Switch S5 prevents U6 from generating a pulse during phase
angle detector circuit adjustments.
H.2.2.9 Directional Coupler Circuit Description
A voltage proportional to RF current from the Output Sample
Board enters the board at J1-3 and J1-5 and is fed to the anodes
of CR28 and CR33. The voltages are taken from opposite sides
of the RF current transformer, so they are 180° out of phase.
Voltage samples are taken from two capacitive dividers on the
Output Sample Board and enter the board at J1-15 and J1-17
The “Forward Balance” adjustment C6 is in parallel with the
voltage divider capacitor on the Output Sample Board.
Under normal operation, P1 and P3 are connected between 1-3.
The voltage and current samples on the Anode and Cathode of
CR33 are 180° out of phase. The DC current flow through R18
establishes a voltage proportional to the current flow and the
square root of forward power. RF choke L1 and capacitor C4
form a filter to remove the RF component and series resistor R20
isolates the coupler from load variations. Resistor R18 and
capacitor C26 also form a low-pass filter to remove audio-frequency variations due to modulation from the coupler’s output.
For the forward power coupler, reversing jumper plugs P1 and
P3 changes the coupler to read reflected power for calibration.
The reflected coupler operates the same way as the forward
coupler, except that the current sample is 180° out of phase.
During VSWR conditions, the phase/voltage relationships at the
ends of CR28 change such that current will begin to flow through
R19. The voltage established through R19 will be proportional
to the square root of the reflected power. Variable capacitor C40
is a balance adjustment, low-pass filter L4 and C13 remove the
RF component and R22 and C22 form a low-pass filter to remove
audio-frequency components. Resistor R22 also isolates the
coupler from load variations. For the “reflected power” coupler,
reversing jumper plugs P1 and P3 changes the coupler to read
forward power to calibrate the reflected power meter.
H.2.2.9.1
Other Power Metering Components
The outputs of the directional coupler go through the LED Board
to voltage followers on the Controller. The voltage follower
outputs drive the power meter on Switch Board/Meter Panel and
the forward and reflected power outputs at the External Interface.
Forward and reflected power calibration controls are located on
the Switch Board/Meter Panel.
H.2.2.10 Detected Audio
Transformer T2 and Diodes CR6 and CR10 form an audio
detection circuit. The output is available at J4 and can be used
to monitor the audio signal.
H.2.2.11 Modulation Monitor Sample
The Modulation Monitor Sample circuit includes relays and
adjustments to provide the same RF output level to the modulation monitor at any power level.
The from adjustable tapped inductor L7, in the Output Network
Compartment, enters the board at J7-1. The signal to the modu-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
H-3
lation monitor at LOW power is adjusted by the tap on L7. When
the transmitter is in the MEDIUM or HIGH power position, the
RF voltage from L7 will increase. Switched potentiometers R7
and R8 reduce the voltage to the desired level.
When relay K2 is energized, the mod monitor sample output is
taken from R7, MED PWR MON ADJ. When both K1 and K2
are energized the sample output is taken from R8, HIGH PWR
MON ADJ. Logic circuits on the LED Board provide logic
HIGH signals when the transmitter is in medium or high power.
A logic HIGH signal at J2-9 will turn on transistor Q4 and
energize low-voltage relay K2 for the MEDIUM power sample.
A logic HIGH signal at J2-7 will turn on Q3 and Q4 through
CR18. This will energize both K1 and K2 for the HIGH power
sample.
H-4
H.2.2.12 +5 VDC And -5 VDC Regulators
DC supply inputs to the Output Monitor are +8 VDC and -8
VDC, from the low voltage power supply. Each input is fused,
with 0.5 A fuses F1 and F2, and regulated to +5 VDC and -5
VDC.
Series pass transistor Q1 is controlled by regulator U1-12. If
U1-9 detects an undervoltage or overvoltage condition, a +5
FAULT-L (LOW) signal is sent to the LED Board at J2-21.
The -5 Volt supply is similar, and uses regulator IC U4, and series
pass transistor Q2.
For a description of the regulator IC’s and circuit operation, refer
to SECTION M, DC Regulator.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section J
Analog Input Board (A35)
J.1 Introduction
This section describes the analog input board and maintenance
and troubleshooting information.
The analog input board includes audio input circuits, part of the
transmitter’s power control circuits, and circuits for optimizing
audio performance. The output signal from this board is an audio
signal with a dc component, which goes to the Digital to Analog
converter board. The dc component determines the transmitter’s
unmodulated (or “carrier”) power output, and the audio component amplitude modulates the transmitter, that is, it changes the
instantaneous output from the transmitter according to the audio
modulating signal.
The analog input board is located on the left side of the non-interlocked compartment.
J.2 Principles of Operation
The Analog Input Board includes the following circuits:
a.
b.
c.
d.
e.
f.
Bessel Filter, to optimize audio overshoot performance.
Transformerless, balanced audio input stage.
“Maximum Power Adjust.”
Power supply hum and noise canceling circuit.
Digitally controlled potentiometer, for power control.
“Dither” circuit for optimizing transmitter noise performance.
g. Audio sample, for the DC regulator.
h. “Digital Power Control” latches and buffers, to drive the
digitally controlled potentiometer.
i. A “PA Turn-Off” circuit.
j. On-board +15, +5, and -15 volt regulators.
Refer to the Analog Input Board Schematic Diagram for the
following description. An overall description of the Analog
Input Board is also included in Section 7, “System Operation.”
This section describes operation of specific circuits on the analog
input board.
J.2.1 Signal Path Through the Analog Input Board
The audio signal passes through a Bessel Filter to the transformerless audio input stage (U6A, U6B, and U9A), which also
includes a GAIN adjustment. Buffer amplifier U7A provides
isolation, and differential amplifier U7B adds a DC “Maximum
Power Control” component to the signal. Analog Multiplier U10
is used as a divider, and a Power Supply Sample input to U10
corrects for power supply voltage changes. A Digitally Controlled Potentiometer circuit (U8 and output stage U11) attenuates
or reduces the (audio + dc) signal to provide High, Medium and
Low power outputs; the digital control signal from the power
control section of Controller Board A38 is stored in latches U17
and U18, buffered by U14 and U16, then goes to the BCD control
03/16/2009
inputs of U8. The (audio + dc) signal is buffered by U4A, then
a “dither” signal is added in U4B. The “dither” signal optimizes
DX-10 noise performance. The output of U4B goes to Analog
to Digital Converter board A34, and a sample of this output also
goes through U5B to DC Regulator A30.
J.2.2 Audio Input
The audio input signal connection to the DX-10 is made at TB3
on the External Interface board (A28). Back-to-back zener diodes on the external interface board provide protection against
transients and excessive voltage at the input.
A shielded audio cable from A28J11 (on the external interface
board) runs to a molex connector, which can be connected to any
one of three audio input connectors on the Analog Input Board
(A35-J1, J2 or J3). Refer to the discussion of the Bessel Filter,
below, for information on selecting the proper audio input connector.
J.2.3 Bessel Filter
The first circuit in the audio signal path is a Bessel Filter, using
passive components (L1 through L4, C1 through C4, and terminating resistors R7 through R12). The Bessel Filter rolls off
frequencies above the audio band, but without introducing overshoot (which is caused by phase shift characteristics of many
types of filters). When heavy limiting is used on the audio signal
to increase “loudness,” the audio wave form can approach a
square wave on audio peaks, and any overshoot introduced by
the transmitter would negate some of the desired “loudness.”
Audio frequency response of the DX-10 is less than 0.9 dB down
at 10 kHz, and square wave overshoot is normally not noticeable
when the filter is properly terminated.
When the Bessel Filter is properly terminated (including the
output impedance of the audio source feeding the transmitter), it
provides high frequency rolloff without adding overshoot. The
source impedance (Rs) of an audio source is not necessarily its
specified load impedance. For example, some equipment using
transformerless outputs can have a source impedance of much
less than 600 ohms (even less than 50 ohms), although it is
intended to operate into a 600 ohm load. The Analog Input board
includes three audio input connectors (J1, J2 and J3), each with
different values of series resistors for different source impedances.
J.2.3.1 Selecting an Audio Input Connector (J1, J2 or J3)
Selecting the proper input connector optimizes high frequency
response and virtually eliminates overshoot. (Selecting another
connector will cause only SMALL changes in audio response
and overshoot).
The Technical Manual for the audio source to the DX-10 audio
input may specify its source impedance. If so, simply plug the
molex connector to the appropriate input on the Analog Input
Board. Use J1 if the source impedance is 600 ohms or more, J2
if it is between 50 and 600 ohms, and J3 if it is 50 ohms or less.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
J-1
If you don’t know the source impedance of the audio source, and
don’t need to optimize performance, use either J1 or J2. If you
wish, however, you can still optimize performance by measuring
high frequency response (above 7 or 8 kHz) and observing
overshoot when modulating the transmitter with a 400 Hz square
wave for each input (J1, J2 and J3) and selecting the best one. If
the source impedance is greater than the analog input board’s
input impedance, some overshoot will result. If the source impedance is less than the analog input board’s input impedance,
high frequency response will change slightly.
J.2.4 Balanced Audio Input Stage (U6, U9)
The audio signal from the Bessel Filter is ac coupled to the input
amplifier, through C5-C6 and C7-C8. Back-to-back zener diodes
CR1 and CR2, and series resistors R11 and R12, provide additional overvoltage protection. Audio Gain Adjust control R15
allows audio input levels from -10 dBm to +10 dBm to be used.
The audio input stage is an “Instrumentation Amplifier,” made
up of three operational amplifiers (two sections of U6 and one
section of U9). An instrumentation amplifier has a balanced
input and unbalanced output; both sides of the balanced input
have high impedances, and the output (at U9 pin 1) is a very low
impedance.
J.2.4.1 “Instrumentation Amplifier” Operation
The first section of the instrumentation amplifier includes two
non-inverting amplifiers with high-impedance inputs. Both noninverting amplifiers have the same gain, which can be adjusted
with Audio Gain Adjust control R15. The second section of the
instrumentation amplifier is a differential amplifier (U9A),
which has two balanced inputs and an unbalanced output.
The two inputs of a conventional differential amplifier have
different gains and different input impedances. In this circuit the
gain at the inverting input (pin 2) is one and the gain at the
non-inverting input (pin 3) is two. A voltage divider between U6
pin 1 and the non-inverting input of U9 compensates for this gain
difference.
Note that the 10k resistors used in this circuit are each one section
of DIP resistor arrays R68 and R69. All resistors are labeled
“R68" or ”R69," and the DIP terminals for each resistor section
are given.
J.2.6 Maximum Power Adjust (U7, R27)
The other half of U7 (U7B) is a differential amplifier with an
audio signal gain of -1 (it inverts the audio signal). The non-inverting input of U7B is an adjustable negative voltage. The
output, at U7 pin 7 (and TP4), will be the audio signal with a
negative dc component.
With the “maximum power adjust” set for 10 kW, the voltage at
TP4 will be about -1.5 volts dc with no modulation. With 100%
modulation, the signal at TP4 will be a 3-volt peak-to-peak audio
signal with a -1.5 Vdc component. The voltage at TP4 will NOT
change when the “Raise” or “Lower” controls on the front panel
are operated or when the transmitter is switched between LOW,
MEDIUM or HIGH powers.
If “maximum power adjust” is set for less than 10kW, the dc
component at TP4 will be between -1.5 volts and 0 volts dc (for
5 kW maximum output power it will be about 1.05 volts; the dc
component at TP4 is proportional to the unmodulated rf VOLTAGE at the transmitter’s output). An instantaneous voltage of
zero volts at TP4 corresponds to NO rf output, which is a -100%
modulation peak at ANY maximum power level.
J.2.7 “Power Supply Sample” Circuit (U10, U12B)
A Power Supply Sample circuit compensates for power supply
“sag,” and reduces hum and noise contributed by the power
supply as well.
J.2.7.1 “Analog Divider” U10
U10 is an Analog Multiplier IC, connected as an analog divider
in this circuit. Resistor R17 sets the “scaling factor” so that the
output of U10 is [4.93 x (Z2-Z1)]/(X1-X2), or (4.93 x audio and
dc offset voltage)/(supply sample voltage).
The “audio plus dc offset” signal from U7 pin 7 is the “Z” input
of U10. The fixed power supply sample (there is no adjustment)
is the “X” input, and is about 5.1 volts, so the “audio plus dc”
output of U10 is slightly less than the input (output =
[4.93/5.1]/[audio plus dc input]).
If the high voltage supply “sags,” for example, at modulation
peaks, the transmitter’s rf output voltage would also “sag.” The
power supply sample decreases slightly, however, and the
“audio plus dc” output of U10 increases slightly to compensate.
J.2.7.2 Power Supply Sample, Circuit Description
J.2.5 Buffer Amplifer (U7)
The output of U9 goes through a voltage divider to the input of
Buffer Amplifier U7A. The buffer amplifier has a gain of 2. The
input to the buffer amplifier can be observed at TP1. When the
DX-10 is modulated 100% with a sine wave, the audio signal
amplitude at TP1 will be about 1.5 volts peak-to-peak with no
dc component.
The positive peak of the audio signal at TP1 corresponds to a
positive modulation peak, and the negative peak corresponds to
a negative modulation peak; the audio signal is therefore not
inverted at this point.
J-2
The “power supply sample” voltage at TP5 and U10’s “X1" input
(pin 10) is determined by the ”supply sample" voltage divider on
fuse board A24 (A24R22, A24R23, and A24R24) and the gain
of non-inverting buffer amplifier U12B.
The high voltage supply sample from fuse board A24 enters the
Analog Input board at J5-8. R29, R65, and bipolar zener diode
CR7 protect U12B against overvoltages, due to transients or
possible failure of the voltage divider.
Operational amplifier U12B is a buffer amplifier, with a gain
slightly greater than 1. Its output is the power supply sample and
goes to input “X1" of divider U10 and to test point TP5.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
J.2.7.3 Protection Circuit: R33, R34, CR9, and Associated
Components
When the high voltage supply is off, the output of U12B is zero.
This could also occur if some “power supply sample” circuit
fault occurs. With no voltage at U10’s “X1" input, the output
would increase toward the -15 volt supply and the transmitter’s
power output would increase to a high level.
If U12B’s output (the “supply sample”) goes too low, diode CR9
conducts and maintains the voltage at U10 pin 10 and TP5 at
about +3.9 volts. Diode CR9 acts as a gating diode. When the
power supply sample is normal, CR9 cathode is more positive
than the anode and the diode is cut off. When CR9 conducts,
resistor R76 limits any current into the output of buffer U12B.
Diode CR10 provides a discharge path for C54 when the +15
volt supply is turned off or if the +15 volt supply fails.
J.2.8 Digitally Controlled Potentiometer (U8) and
Output Amplifier (U11)
Integrated Circuit U8 is a 3-1/2 digit Digitally Controlled Potentiometer (an attenuator). A 12-bit BCD (Binary Coded Decimal)
digital power control signal, at U8 pins 4 through 15, controls
the output of U8. The output of the U8/U11 circuit will be from
0.000 to 0.999 times the input (at U8 pin 17). The “1" digit is not
used in the DX-10. The dc component of the attenuator’s output
determines the ”carrier" power, and the audio component modulates the transmitter’s output.
The output impedance of U8, at pin 1, depends on its attenuation.
For good linearity, an external op amp with a low offset voltage
is required. Integrated circuit U11 is a low-noise, low-offset
voltage precision operational amplifier which meets this requirement and provides a constant output impedance to following
circuits. The feedback resistor for op amp U11 is part of U8.
Schottky diode CR3 protects the output of U8, and capacitor C34
ensures amplifier stability.
The digitally controlled attenuator circuit, then, is made up of
both U8 and U11. The output, at U11 pin 6 and TP7, is V(out) =
-V(in) x DAC, where DAC is the binary coded decimal input
(0.000 to 0.999 in this circuit). At rated power with 100%
modulation, the output will be a 3-volt peak to peak audio signal
with a +1.5 volt dc component. At lower power levels, both the
audio and dc components will be smaller by the square root of
the power ratio.
J.2.8.1 BCD Logic Input to Digitally Controlled Attenuator
U8
The digital power control logic input for U8 is on pins 4 through
15. For each input (for each BIT of the BCD input), a logic “0"
is near zero volts, and a logic ”1" is near +15 volts. The BCD
power control signal is generated on Controller Board A38, and
on the Analog Input Board is stored in TTL latches U17-U18 and
converted to CMOS logic levels by hex level shifters U14 and
U16.
ator output of zero), inputs D1 through D12 would be “0000 0000
0000"; for a BCD input of 0.500, the inputs would be ”0101 0000
0000," and for maximum output from the attenuator (BCD input
is 0.999), D1 through D12 would be “1001 1001 1001.” A further
description of BCD coding used in the DX-10 is included, for
reference, after the paragraphs on “Troubleshooting” in this
section.
J.2.9 Analog Input Board,, BCD Power Control In-
puts
The Power Control Signal from Controller A38 enters the Analog Input board at J4 terminals 1 through 24. These inputs are
TTL level logic signals. Odd numbered terminals of J4 are logic
signal lines and even numbered terminals are ground.
The power control logic signal comes from tri-state logic outputs
on the controller board. Pull-down resistors, in DIP resistor
arrays R47 and R48, ensure that each line is at ground unless one
of the tri-state logic outputs on that line are “HIGH.”
J.2.10 Power Control Latches, U17-U18
The BCD Power Control data is stored in TTL latches U17 and
U18, 6 bits of the 12 bit signal are stored in each latch. The
“RESET” and “CLOCK” inputs of the latches are tied together.
J.2.10.1 “Clock” Input (“Data Strobe” or “Auto Strobe”
Pulses)
The clock input to both latches is from the output of U13-6. Data
stored in latches U17 and U18 changes when a transition from
LOW to HIGH logic level occurs at the clock input (pin 11) of
each latch. The latch will store the data present at its inputs at
that instant, and that data will then remain in the latch until the
latch is either CLEARED or another positive-going transition
occurs at the CLOCK input.
J.2.10.2 “Reset” Input (Data Clear)
A “Data Clear” (logic LOW) signal from Controller A38 occurs
if any of the supplies on the controller fails, and RESETS all
outputs of both latches to Zero (corresponding to zero power
output from the PA). The Data Clear input is buffered by two
sections of U13 and goes to the “reset” inputs of U17 and U18.
The buffered Data Clear input also goes to AND gate U15D (pin
13) in the AUTO STROBE circuit.
J.2.10.3 TTL to CMOS Level Shifters (U14, U16)
The logic outputs of latches U17 and U18 are TTL level logic
signals Hex level shifters U14 and U16 shift these to the CMOS
level logic signals required by digitally controlled potentiometer
U8.
J.2.10.4 Analog Buffer Stage (U4A)
Buffer stage U4A is a non-inverting amplifier with a gain of +2
Series resistor R82 and JFET switch Q7 (part of the PA Turn Off
circuit) form a voltage divider to ground at its input. When JFET
Q7 conducts, U4A’s input is essentially zero, so the PA output
will be zero (all PA modules are turned off).
Inputs D1 through D4 are the binary bits for the first (most
significant) decimal digit, D5 through D8 are the bits for the
second decimal digit, and D9 through D12 are the bits for the
third (least significant) digit. For a BCD input of 0.000 (attenu03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
J-3
J.2.11 PA Turn On/Turn Off Circuit (U13-2, Q1,
Q7, U13-4, Q2, Q8)
The Q2 and Q8 circuitry is identical to that of Q1 and Q7 with
the exception of additional components used to create the “Half
Power Step-Up” during the turn on sequence.A “PA Turn OffH” signal is generated by the Controller during fault protection
and when the transmitter is turned OFF. This logic HIGH input
to U13-1 from J4-39 will be inverted to a logic LOW at U13-2.
This will turn Q1 ON and apply a positive voltage to Q7 through
Q1 and R20.
Transister Q7 is an N-channel depletion mode JFET switching
transister. When the gate of Q7 approaches zero Volts it conducts
(turns ON) and the drain-source resistance becomes less than 80
Ohms. Transistor Q7 and R82 form a voltage divider, so when
Q7 is ON, it effectively shorts the (Audio + DC) signal at U4-3
to ground.
When the transmitter is turned ON, the “PA Turn Off-H” signal
goes to logic LOW and turns off Q1 through U13. The gate of
Q7 is pulled to -15 Vdc by R25 which will turn it OFF. When
Q7 is OFF it is an open circuit and the (Audio + DC) signal is
applied to U4-3. During normal operation, Q1 is not conducting,
C46 is charged to -15 Vdc through R45, and Q7 is OFF.
Transistor Q8 and R23 form a second JFET voltage divider with
R82. This circuit is in parallel with Q7. When Q8 is turned On,
the series resistor R23 will cause the (Audio + DC) signal at U4-3
to be attenuated, but not shorted to ground.
Transistor Q8 will conduct longer than Q7 due to the delay
circuit C86 and R49 on the U13-3 input. When the “PA Turn
Off-H” signal changes from HIGH to LOW, C86 discharges
slowly through R49, and keeps Q2 conducting. When the “PA
Turn Off-H” signal is generated, C86 charges quickly through
CR20 to reset the circuit.
This allows the RF power to come up in a two-step sequence:
first to half power, then, after a 1.5 to 2 second delay, full power.
The delay minimizes stress on the power supply and will give
antenna system components time to “settle down” or cool after
an arc has occurred, i.e. the antenna ball gaps and/or guy wire
insulators
J.2.12 Differential Amplifier/Inverter U4B
For the audio plus dc signal, U4B is an inverting amplifier (gain
is -1). The non-inverting input is a very small signal from the
“Dither Oscillator.” Differential amplifier U4B adds this
“dither” signal to the (audio + dc) signal. For full power output
with 100% modulation, the signal at U4B’s output (pin 7) is a 6
V p-p audio signal with a -3 volt dc component and a very small
72 kHz “dither” component.
J.2.13 “Dither” Signal: Function
The “Dither” signal optimizes noise performance in the DX-10.
Transmitter noise performance is good even without the “dither”
signal, but can be improved with proper adjustment of Dither
Level.
Dither frequency is set at 72 kHz. This frequency is well above
the audio frequency range, but low enough so that any 72 kHz
J-4
sidebands are attenuated by the bandpass filter/output network.
If the dither frequency is too high or the dither level is too large,
the sidebands will not be attenuated sufficiently and will appear
as unwanted spurious signals.
If a dither circuit fault is suspected and equipment is not available
to properly adjust the dither level, the “Dither Level Adjust”
control can be simply turned to minimum (fully counterclockwise). If either “Dither level” or “Dither frequency” are too high,
unwanted spurious sidebands can occur.
J.2.14 Dither Oscillator (U3, U19, and U5A)
The Dither Oscillator is made up of an integrator (U3) and a
square wave generator (differential amplifier U19). The output
of the Dither Oscillator, at U3 pin 6 and TP10, is a triangle wave
with an amplitude of 1 volt peak-to-peak and a frequency of 72
kHz. A synchronizing signal from Analog to Digital Board A34
is buffered by op amp U5A. A voltage divider (R42 and “dither
level adjust” potentiometer R43) reduces the dither signal level
to a very low level at TP9 and U4 pin 5.
J.2.14.1 Oscillator Circuit Description
The following description refers to the Analog Input Board
schematic diagram.
J.2.14.2 Square Wave Generator U19
U19 operates “open loop,” so its gain is very high, and it operates
as a comparator. Assuming no “Big Step Sync” input, the inverting input (U19 pin 2) is at zero volts. If the voltage at the
non-inverting input is even slightly positive the output will go to
the +15 V supply rail; if the voltage is negative, the output will
go to the -15 V supply rail. The output of U19 is limited by series
resistor R38 and zener diodes CR11 and CR12 so that at CR11
anode it is either +6 V or -6 V (this voltage is the 5.1 volt zener
voltage plus the 0.7 volt forward junction drop of the other
diode).
J.2.14.3 Integrator U3
The voltage at the input to potentiometer R41 is then either +6
volts or -6 volts. The integrator’s input is at the inverting input,
so that when the input is +6 volts the output of U3 (at pin 6) will
ramp DOWN (go less positive/more negative), and when the
input is -6 volts, the output of U3 will begin ramping UP. The
rate at which the output of U3 changes is determined by the
R41-C62 time constant, so that adjusting R41 will adjust the rate
of change of U3’s output and therefore the oscillator’s frequency.
J.2.14.4 Dither Oscillator Circuit Operation
With no sync input to U5A, the output, at U3 pin 6 and TP10,
will be a triangle wave ramping between +1 and -1 volt, at a
frequency set by R41 (nominally 72 kHz). The signal at zener
diode CR11’s anode will be a square wave, switching between
+6 and -6 volts at the same frequency.
Resistors R39-R40 and zener diodes CR11-CR12 set the oscillator’s output level, the peak voltages at U3 pin 6. R39 and R40
form a voltage divider, with one end at either +6 or -6 volts (fixed
by the zener diode voltages) and the other end at the oscillator’s
output voltage (a triangle wave varying between +1 and -1 volt).
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Suppose that U3 output is +1 volt and the input (to variable
resistance R41) at that instant is +6 volts. The non-inverting input
of U19 is then +1.75 volts, set by divider R39-R40. The output
of integrator U3, however, will be ramping down. U19’s non-inverting input will remain positive (but will also be ramping
down) until the output of U3 reaches about -1 volt, and the
voltage divider (R39-R40) has -1 volt at one end and +6 volts at
the other. Now, U19’s non-inverting input will go slightly negative, forcing the output of U19 negative.
At the instant that the output of U19 goes negative, one end of
the voltage divider (R39-R40) is -1 volt and the other end is -6
volts. The non-inverting input of U19 is now about 1.75 volts
negative and U19 output is forced to remain negative. Integrator
U3 begins ramping UP and U19’s non-inverting input also ramps
up until the output of integrator U3 reaches about +1 volt,
causing U19’s input to go positive and beginning the cycle again
(this is the condition at the beginning of the previous paragraph).
The output of U3, at U3 pin 6 and at TP10, is a triangle wave,
ramping alternately up and down between +1 and -1 volt. This
output is reduced by adjustable voltage divider R42-R43 to
provide the small “dither” signal to U4 pin 5. This signal, at TP9,
is too small to observe with an oscilloscope; the probe will also
pick up enough noise to mask the dither signal.
J.2.15 “A/D Big Step Sync” Input to Dither Oscilla-
tor
The “Big Step Sync” signal from the A/D Converter (A34)
consists of a short pulse each time a “Big Step” occurs. The sync
pulses are buffered in non-inverting amplifier U5A, then go to
pin 2 of U19, in the Dither Oscillator, as synchronizing pulses.
If the dither signal is ramping UP when a “Big Step” is turned
OFF the Big Step Sync pulse will change the direction of the
dither signal so it ramps DOWN. If the dither signal is ramping
DOWN when a “Big Step” is turned ON, the sync pulse will
cause the dither signal to change and ramp UP.
J.2.16 -(Audio + DC) Sample to DC Regulator
The DC regulator provides a modulated negative “bias voltage”
to the PA modules to change or ‘modulate’ their turn on/turn off
times to minimize “glitches” (transient pulses in the combined
rf output) as modules switch on and off. The “GAIN” and
“OFFSET” controls on the Analog Input board are adjusted
along with two other controls on the DC Regulator (A30). Refer
to Section M, DC Regulator, for a further description and to the
Tuning/Frequency Change procedure in Section 5, “Maintenance” for procedures for adjusting these controls.
J.2.16.1 (Audio + DC) Sample Circuit Description
A sample of the output signal from the Analog Input Board is
attenuated by voltage divider R72, and R81, and fed to the
non-inverting input of differential amplifier U5B. The inverting
input of U5B (pin 6) is a positive voltage, adjustable from 0 to
+15 volts with “OFFSET” control R84.
The output of U5B, at pin 7, is an inverted audio signal with an
adjustable dc offset (the audio signal is “inverted” because
positive peaks are most negative at this point). The “Gain”
03/16/2009
control adjusts the (audio + dc) level and the “Offset” control
changes just the dc offset, from that set by the Maximum Power
Adjust control.
This signal goes to the DC regulator where it modulates a
negative supply on the DC regulator to provide the “Modulated
B- Supply.” Refer to section M, DC Regulator, for more information.
J.2.17 Analog Input Board Power Supplies
Supply voltages to the analog input board are +22 V and -22 V
unregulated, from the low voltage power supply. Voltage regulator U2 provides a -15 volt output. Voltage regulator U1 provides +15 volts, and resistor R66 and zener diode CR15 provide
+5 volts. Both regulated supplies are fused. The regulators
provide “Supply Fault” outputs to fault and overload circuits on
Controller A35. Refer to Section M, “DC Regulator” for a further
description of these voltage regulator circuits.
J.2.18 “Dither”: A Description
The Analog to Digital (A/D) conversion process has an inherent
+/- 1 digit uncertainty. As the analog input changes, there may
be some switching back and forth between two “steps” because
of this uncertainty. When the DX-10 switches between “Big
Steps,” this can cause “glitches” or spikes on the modulation
envelope; these are filtered out by the bandpass filter, but some
low-level residual noise remains. The “Dither” signal minimizes
this residual noise.
The “Dither” oscillator introduces a small 72 kHz triangle wave
on the signal. If this dither signal is synchronized so that it
increases just as the transmitter output switches from a condition
where all Binary Steps are “ON” to the next “Big Step” with all
Binary Steps “OFF,” the A/D analog input is forced higher
quickly enough to prevent switching back and forth between the
“Big Steps.”
When the transmitter output is decreasing, the dither signal is
synchronized so that it is also decreasing just as the PA switches
from a state with all Binary Steps “OFF” to the next step down,
where a Big Step turns off and all the Binary Steps turn ON.
J.3 Maintenance
J.3.1 Printed Circuit Board Maintenance Procedures
Refer to section 5, “Maintenance,” in this technical manual for
general printed circuit board preventive maintenance procedures.
J.3.2 Replacing CMOS Devices
CMOS Devices are sensitive to electrostatic discharge, and may
be damaged if unconnected devices are subjected to high electrostatic fields. Refer to section 5, “Maintenance,” in this technical manual for precautions when handling and replacing
CMOS devices.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
J-5
CMOS devices requiring special handling on this printed circuit
board include the Digitally Controlled Potentiometer (U8),
Latches U17 and U18, and gates U13 and U15.
J.3.3 Adjustments
J.3.3.1 “Audio Gain Adjust,” R15
With the transmitter operating at Low Power (as a precaution
against overload due to excessive modulation levels), apply a
sine wave at the level which is to produce 100% modulation, to
the transmitter audio input terminals (TB3 on External Interface
A28). Adjust “Audio Gain Adjust” R15 for 100% modulation.
J.3.3.2 Maximum Power Adjustment (R27, “MAX PWR
ADJ”)
Turn the transmitter on at “HIGH POWER,” depress the
“RAISE” pushbutton until transmitter output increases to the
desired “maximum power,” adjust R27 counterclockwise to
reduce the power, then depress the “RAISE” pushbutton again
(you may need to go back and forth until the “RAISE” control
no longer increases power). When the “RAISE” pushbutton no
longer increases power, make the final adjustment of R27.
An alternate procedure is to turn “Max Pwr Adj” several turns
counterclockwise, depress the “RAISE” control until maximum
power is reached, then make the final adjustment of “Max Pwr
Adj” R27.
Typically, “Maximum Power” should be set about 10% above
the desired transmitter power output to allow operators some
adjustment range.
NOTE
Operating power required may be more than 10 kW in some installations, because of antenna system losses. Refer to the station
license for required transmitter power output.
J.3.3.3 Dither Frequency Adjust, R41
Adjust R41 for a Dither Frequency of 72 kHz. If Dither Frequency and/or amplitude is too high, unwanted spurious outputs,
primarily sidebands at the dither frequency, could result.
J.3.3.4 Dither Level Adjust, R43
A triggered-sweep oscilloscope and modulation monitor or other
low-distortion, wide-band envelope detector is required to adjust
Dither Level. A spectrum analyzer is also desirable, to monitor
spurious signals in the transmitter’s rf output.
At High Power, modulate the transmitter at a low level (about
20%) with a 100 Hz sine wave. While observing the detected
modulation, expand the oscilloscope display both vertically and
horizontally until the “binary steps” can be seen. You can turn
bits 11 and 12 on and off with the “Bit 11" and ”Bit 12" sections
of DIP switch S1 on Modulation Encoder board A36 to make the
steps more visible; turn bits 11 and 12 back on before adjusting
Dither Level.
When Dither Level is correct, the steps in the demodulated
output will be rounded off and may not even be visible. If Dither
Level is too low, the smallest binary steps will be seen when the
oscilloscope display is expanded enough. If Dither level is too
high, the 72 kHz signal will appear on the steps (as “grass” or
noise), and 72 kHz sidebands will be seen on the spectrum
analyzer. Adjust Dither level for a compromise between these
J-6
conditions. Two turns CW (clockwise) from minimum is a
typical adjustment position.
Proper adjustment of Dither level can also be confirmed by
measuring noise with an audio noise meter (audio analyzer) at
the output of a high quality modulation monitor. Correct adjustment of Dither Level will reduce noise by several dB.
NOTE
If proper test equipment is not available and excessive “Dither
Level” is suspected as contributing to noise or to spurious output, simply turn Dither Level Adjust control R43 fully counterclockwise. Transmitter noise performance will still be good if the
transmitter is operating properly.
J.3.3.5 “Offset” Adjust, R84
Refer to the tuning/frequency change procedure in Section 5,
Maintenance. This is one of four interacting adjustments, including “Gain” Adjust R85, and two on the DC Regulator board.
J.3.3.6 “Gain” Adjust, R85
Refer to “Offset” Adjust R84 (above).
J.4 Troubleshooting the Analog Input
Board
Observing waveforms and voltages at Test Points with an oscilloscope, with a sine wave at the audio input, will isolate most
faults to one stage of the Analog Input board. (The sine wave
amplitude should be the level normally required for 100% modulation; signal levels for this input are indicated on the schematic
diagram and given in Table J-2, “Analog Input Board Test
Points”).
Some specific symptoms and possible causes are described in
the following paragraphs.
J.4.1 Symptom
Normal Signal at TP4, No Signal at TP7 (Digitally Controlled
Potentiometer Output).
J.4.2 Possible Causes
J.4.2.1 U8, U10, or U11 faulty
Check U10 output/U8 input (Caution: don’t short adjacent IC
pins!) If no signal is present, U10 is probably faulty. (If the
transmitter’s high voltage is not on, the signal at this point will
be somewhat larger than normal). Check U8 Output (at CR3
cathode); if (audio + dc) signal is present, U11 is probably faulty.
If (audio + DC is present at U8 input but not at U8 Output, refer
to the following paragraphs.
J.4.2.2 Digital Control Signal at U8 is Zero
(REMOVE AUDIO INPUT TO CHECK). There are several
possible causes, including:
a. BCD (Binary Coded Decimal) Control Signal from Controller A38 is Zero. Use an oscilloscope or meter to check
Power Control Lines (odd-numbered pins 1 through 23 at
J4). If the four most significant bits (D9 through D12) are
zero, the controller is setting the transmitter’s power out-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
b.
c.
d.
e.
f.
put to a very low level. Refer to Section P, Controller
Board, for further troubleshooting information.
DATA CLEAR Input (at J4-27) is LOW. If the data clear
input is less than about +1 volt, the controller is instructing
the data latches (U17-U18) to CLEAR, that is, reset to
zero. Refer to Section P, Controller Board, for further
troubleshooting information.
No Data Strobe Pulses (At J4-25). TTL-level Logic High
pulses from the Controller Board should appear at this
point.
Inhibit Gate Input is LOW (At TP15). There should be a
dc voltage of +3 volts or more at TP15. If not, check the
logic circuits before TP15.
Defective U17 (or U18). If there is BCD data from the
controller, the “DATA CLEAR” inputs are HIGH, and
Data Strobe (High) pulses are present, but there is no
output from one or both latches, the latches may be defective.
Defective Logic Drivers (U14, U16). For each logic driver
section, the input and output should always be the same.
J.4.2.3 Power Increases or Decreases in Steps, Not Continuously
This indicates that some bits or digits in the BCD power control
signal are not changing or that one or more PA modules have
failed. Check the logic level signals for the BCD Bits at different
power levels, at J4, at U18 outputs, and at U14 outputs.
• BCD (Binary Coded Decimal) Coding
The following information is included for reference, if missing
bits in the BCD Power Control signal is suspected as a problem.
For the two most significant bits, you should be able to use the
“raise” and “lower” controls to change power one “step” at a
time and measure logic level signals with a logic probe, voltmeter, or oscilloscope.
The Binary Coded Decimal input to the Digitally Controlled
Attenuator in the DX-10 consists of three decimal digits, from
03/16/2009
0.000 to 0.999. If this number is represented as “0.XYZ,” “X” is
the most significant digit, “Y” is the next most significant digit,
and “Z” is the least significant digit.
Each digit is represented in Binary form, as follows:
Decimal
Digit
Binary
Number
Decimal
Digit
Binary
Number
0
0000
5
0101
1
0001
6
0110
2
0010
7
0111
3
0011
8
1000
4
0100
9
1001
The complete “BCD” number is represented as “XXXX XXXX
XXXX,” where each “X” (Binary “BIT”) can be either “0" or
”1." The binary BITS are also represented on the schematic
diagrams as D1 through D12, so that the BCD number appears
in the following order:
D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12
For reference, several DX-10 power levels are represented below
in both decimal and BCD notation. (Maximum power is set by
the “Max Pwr Adj” control R27).
Power Level
Decimal
BCD (Binary Coded Decimal)
Maximum Power
0.999
1001 1001 1001
One-half power
0.707
0111 0000 0111
One-fourth power
0.500
0101 0000 0000
One-tenth power
0.316
0011 0001 0110
Zero power
0.000
0000 0000 0000
Prior to starting a troubleshooting procedure check all switches,
power cord connections, connecting cables, and power fuses.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
J-7
Section K
Analog To Digital Converter (A34)
K.1 Introduction
This section describes the Analog to Digital Converter board
description, maintenance and troubleshooting.
The schematic diagram can be found in the Drawing Package
and the parts list can be found in Section VII. “Analog to Digital
is also referred to as ”A/D" or “A to D”. The A/D board is located
in the center control compartment.
K.2 Principles of Operation
An analog audio signal from the Analog Input board goes to the
A/D board where it is converted to a 12-bit digital audio signal
by an A/D chip. The rate of this conversion is 1.2 to 2.5 microseconds depending on the transmitter frequency. The A/D conversion process is synchronized with the RF signal so that PA
modules are switched on and off when the RF driver current
crosses through zero and the PA transistors are not conducting,
called the “zero crossing”. The digital audio signal from the A/D
is stored in latches.
The latch outputs go to the Modulation Encoder board where
they are used to turn on PA modules. The latch outputs also go
to the reconstruction audio circuit and to the big step sync circuits
on the A/D board. The reconstruction audio signal goes to the
envelope error circuit on the Controller board (A38). The big
step sync signal goes to the dither oscillator on the Analog Input
board.
The following description refers to the schematic diagram for the
Analog to Digital Converter board (drawing 839-7855-177).
Refer to SECTION V, Maintenance, for adjustment and pc board
maintenance procedures.
Refer to SECTION IV, Overall System Theory, for a block
diagram and overall descriptions of the audio and digital audio
sections of the transmitter.
K.3 Circuit Description
K.3.1 Converting a PA Sample to the A/D EN-
CODE Pulse (T1, U29, Q9)
There are two RF sample inputs to the A/D converter board. One
is the Splitter Sample Frequency Input from the RF Splitter
(A15) on pins J3-1 and J3-2.
The other is the Output Sample Frequency Input from the output
combiner on pins J8-1 and J8-2. The input network for this
sample is an R-C-L network which provides a fixed 90 degree
phase shift at 525 kHz. Jumper plug P11A-P11B allows disconnecting this sample.
03/16/2009
PA modules must be switched on and off when the RF drive
crosses through zero. During modulation this timing requirement
shifts slightly especially at the low end of the transmitter’s
frequency range, so samples of RF drive and RF output which
are 90 degrees out of phase are added together. The two samples
are added vectorially in R62. The resulting output is phaseshifted by about +/-15 degrees (at the low end of the band) during
modulation.
The RF input goes to the primary winding of wide-band toroidal
RF transformer T1. Resistor R18 and an L-C network with
components selected by section of DIP switch S1 provide adjustable, frequency-determined phase shift (refer to the Tuning/Frequency change procedure in Section 5, Maintenance for
information on setting S1).
Schmitt Trigger U12C converts the RF input to TTL level pulses.
Diodes CR14 and CR15 limit the voltage at the Schmitt trigger’s
input to between +0.7 and +4.3 Volts.
K.3.2 Frequency Divider (U29, Q9 )
The frequency output at TP6 is at the RF input frequency (from
J3 pin 1) if the jumper plug is installed between JP10 pins 5 and
6,. The output at TP6 is at one-half of the RF input frequency if
the jumper is installed between pins 1 and 2. The output at TP6
is at one-third of the RF input frequency if the jumper is installed
between pins 3 and 4.
The position of the jumper plug JP10 depends on the transmitter’s operating frequency. Refer to the note on the A./D converter
schematic diagram or to the Frequency Determined Components
chart.
K.3.3 ENCODE Signal Pulse Width (Q9)
The timing diagram labeled A/D Converter Board Signals shows
the interaction of signals on this board. The signal on TP6 goes
through C106. The base of Q9 is held at about 0.7 V. The falling
edge of the pulse from TP6 causes Q9 to turn off. This allows
the collector of Q9 to increase in voltage. R78 and R79 charge
up the base of Q9, turn it on again and cause the collector to drop
0.3 V. The end result is a pulse at TP3. The length of this pulse
depends on the value of resistors R78 and R79. This pulse width
should be between 20 and 50 nanoseconds. This is the ENCODE
signal that goes into the A/D and starts the conversion process.
K.3.4 Analog to Digital Converter Circuit
K.3.4.1 Analog Input Circuit (U28)
The analog input signal (J4-10) to the A/D converter is the Audio
+ DC from the Analog Input board (actually the negative Audio
+ DC). The DC component determines the unmodulated transmitter power output (“carrier” level) by turning on a constant
number of PA modules. The audio component amplitude modulates the output by turning PA modules on or off to vary the
instantaneous RF output voltage.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
K-1
The analog signal level at the board’s input is high so that any
noise pickup on interconnecting cables does not degrade the
signal-to-noise ratio. Inverting amplifier U28 has a gain of 0.5
to provide the proper single level to the A/D chip input and also
provides isolation between the board’s input and the A/D chip.
A very small amount of signal from the big step sync circuit is
added to the input signal through R70 at the inverting input of
U28 (pin 2). When a big step occurs in the output the last-bit
uncertainty in the A/D conversion process could cause a transition back to the previous step. This will produce a “glitch” or
spike in the modulated output as the unwanted switching between big steps takes place. The small voltage from the big step
sync circuit forces the input higher, just enough to ensure the
A/D converter will not switch back to the previous step.
High-speed Schottky diodes (CR16, CR18) protect the A/D’s
(U1) input against overvoltages. Schottky diodes also have low
turn-on voltages, 0.5 Volts or less. CR16 prevents the voltage
level input from going negative. CR19 prevents the voltage level
from going higher than about +5 Volts since CR10 is a 4.7 Volt
zener diode.
K.3.4.2 Analog to Digital Converter (U1, DL1)
A 12-bit analog to digital converter AD1671 is used. Conversion
time of the AD1671 is less than 800 nanoseconds. The analog
input voltage range is 0 to +5 Volts. An input of 0 Volts gives a
digital output of “0000 0000 0000". An input of +5 Volts gives
an output of ”1111 1111 1111".
The analog signal that is going to be converted to digital goes
into the A/D chip at pin 23. The ENCODE pulse goes into the
A/D chip at pin 17 and tells the A/D to do a conversion.
The 12 A/D output data lines are at pins 2 through 13. Pin 2 is
the least significant binary bit (LSB) and pin 13 is the most
significant binary bit (MSB). Pin 16 is the DAV pin (data
available pin). DAV is a negative pulse that indicates when a
conversion is complete and data is valid on the 12 output lines.
The DAV pulse goes into a 450 nanosecond delay chip, DL1.
This delay is used to make this A/D board (843-5100-094 Rev
A) compatible with the previous A/D board (843-4038-049 Rev
P). The old version of the A/D board used a slower A/D chip that
was taken out of production.
K.3.4.3 Digital Data Latches (U3, U4, DL3)
The negative pulse from DL1 also goes to a 60 nanosecond delay,
DL3. The output from DL3 is the LATCH STROBE pulse. The
rising edge of this pulse latches the digital audio information
from the A/D converter into U3 and U4.
The digital audio data from latches U3 and U4 also goes to two
digital to analog (D/A) converters. D/A U22 is part of the big
step sync circuit and D/A U8 is part of the reconstructed audio
circuit.
The negative pulse from DL1 goes to the input of U7 pin 1 and
is the signal DATA STROBE-L on J6-26. The signals on the J6
connector go to the Modulation Encoder board. The rising edge
of the DATA STROBE-L is used to transfer the bits from latches
U3 and U4 into latches on the Modulation Encoder board.
K-2
K.3.5 Error Detecting Circuits
There are circuits on the A/D board that determines if the clock
signal is being received and if the A/D converter is working
properly. The error detection circuits use three re-triggerable
monostable mulitvibrators, called one-shots. If an error is detected the logic signal CONVERSION ERROR-L will go low
and clear the storage latches on the A/D board and the storage
latches on the Modulation Encoder board.
K.3.6 One-Shot Operation (U13, U14)
One-shots produce an output pulse each time a rising or falling
edge is detected on the input. Each one-shot has three inputs; A,
B and CLEAR. Each has two outputs; Q and QN (not-Q). There
is an RC network connected to each one-shot which determines
the length of the pulse.
The following table logic low will be 0 and logic high will be 1.
Up is the rising edge of a pulse and down is the falling edge. X
denotes that either a 0 or 1 may be present.
A
0
down
0
1
X
X
B
up
1
1
X
0
X
CLEAR
1
1
up
X
X
0
Q
pulse (pos.)
pulse
pulse
0
0
0
One-Shot Operation Table
Re-triggerable means that if an input trigger condition occurs
again during an output pulse, the R-C network will be reset and
the pulse will be extend for the R-C time constant.
K.3.6.1 Power Up Reset (C41, R16, U12-F)
When the +5 Volt supply first comes on, the signal POWER UP
RESET-L (TP2) will be low for about 5 milliseconds. This logic
low clears the error detection one-shots (U13, U14). The signal
CLEAR-L (TP17) will be low which will clear the A/D latches
(U3, U4). The signal DATA CLEAR-L (J6-28) will also be low
and will clear the latches on the Modulation Encoder board.
Setting all latches to zero for 5 milliseconds will allow time for
power supplies to reach full voltage before any PA modules are
turned on and will also remove any data that might be entered in
any latches by transients during power-up.
The +5 Volt supply initially comes on causing C41 to charge
through R16 and the voltage at the inverter Schmitt trigger
U12-F to increase from zero. When the voltage across C41 goes
above the threshold of the inverter, the output will go high.
If the +5 Volt supply voltage fails, C41 will discharge through
diode CR13. The signal POWER UP RESET-L will again be
low.
K.3.6.2 Clock Error Detection Circuit (U14-A)
The clock frequency TP6 can be from 410 kHz to 820 kHz so
the period is 1.2 to 2.5 microseconds. This is the input to pin 2
of one-shot U14-A. The output of the one-shot is labeled CLK
ERROR-L. The one-shot output pulse is 3.6 microseconds long.
As long as the clock pulses are present the one-shot continues to
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
re-trigger and the output will remain 1. If the pulses stop or the
frequency is too low the one-shot output will go low.
K.3.6.3 A/D Converter Monitor Circuit (U13-A)
The signal DAV at TP5 comes from the A/D converter after each
conversion. The period of this signal is 1.2 to 2.5 to microseconds. This is the input to pin 2 of one-shot U13-A. The output
of the one-shot is labeled A/D ERROR-L. The one-shot output
pulse is 3.6 microseconds long. As long as the DAV signal is
present, the one-shot will continue to re-trigger and the output
will remain 1. If the pulses stop or the frequency is too low, the
one-shot output will go low.
K.3.6.4 Conversion Error Indicator (U14-B, U11, DS1)
The signals CLK ERROR-L and A/D ERROR-L go into AND
gate U15-A. The output of this gate is the signal CONVERSION
ERROR-L at TP8. If the signal CONVERSION ERROR-L goes
low, it triggers one-shot U14-B. The output of this one-shot will
be a low pulse at pin 12 for 10 microseconds. This low propagates through U15-B and U15-C and causes the signal CLEAR-L
to go low. This ensures that any error will cause the bits that are
driving the PA modules to be cleared for at least 10 microseconds.
Operational amplifier U11B functions as a comparator with the
inverting input level set at about +1.4 Volts by the R28-R29
voltage divider. If there is an error, then U15 pin 6 will have a
lower voltage then pin 5. U11 pin 7 will be -15 Volts. This will
cause bicolor LED DS1 to indicate RED. If there is no error, then
U15 pin 6 will have a higher voltage than pin 5. U11 pin7 will
be +15 Volts. This will cause bicolor LED DS1 to indicate green.
The signal CONVERSION ERROR-H goes to the LED board
A32 and is high if an error has occurred.
K.3.7 Big-Step Sync Circuit
The big step sync circuit produces a pulse each time a big step
occurs in the transmitters output. In the DX 10 and the DX 25 a
big step occurs whenever a change occurs in any of the six most
significant bits from the A/D chip. In the DX 50 a big step occurs
whenever a change occurs in any of the seven most significant
bits from the A/D chip.
K.3.7.2 Amplifier Stage (U24, U25, U26)
The output of the A/D converter is amplified by U24 and U25.
The gain of the amplifier stage is slightly over 5. U24 is an
operational amplifier and U25 is a current amplifier that’s used
to increase the current output capability of the amplifier to drive
the next stage without degrading the stepped waveform.
The low-pass filter R53-C93 removes any high frequency components. U26 is a buffer stage. The output of U26 is added,
through R70, to the analog input signal. The output of U26 also
drives a differentiator.
K.3.7.3 Differentiator and Buffer (U27)
R55 and C92 form a differentiator which produce a pulse each
time a transition occurs. The pulses can be observed at the output
of U27 pin 6 or at R63. The output signal from U27 is the big
step sync pulses which go to the dither oscillator circuit on the
Analog Input Board (A35).
K.3.8 Reconstructed Audio Circuit
An audio signal is reconstructed on the A/D board by sending
the bits into D/A converters U8. Another audio signal comes
from the envelope detector at the transmitter’s output. These two
audio signals are compared at the envelope error circuit on LED
Board A32. (Refer to Section Q, LED Board, for a discussion of
the envelope error circuit).
K.3.8.1 Reconstructed Audio Circuit D/A converter (U8)
The 12-bit digital audio signal is converted back to an analog
signal by D/A converter chip U8, operational amplifier U9 and
current amplifier U10. The unfiltered D/A converter circuit’s
output is at U10 pin 8 and is available for viewing at test point
TP9. Voltage divider R31-R30 isolates the D/A converters output from any loading by test equipment. The unfiltered output at
TP9 varies between 0 and 5 Volts when observed using a
high-impedance probe .
K.3.8.2 Reconstruction Filter (L1, L2, L3, C47, C48, C49)
The big step sync pulse synchronizes the “dither” oscillator on
the analog input board. Also the big step sync adds a small
amount of voltage to the analog input signal that goes into the
A/D chip. This small amount of voltage is to minimize undesired
switching back and forth between the big steps.
The D/A converters output is stepped. The reconstruction filter
is a low-pass filter which passes the audio components and
removes the higher frequency components in the steps. This
smooths the output (a D/A reconstruction filter is also sometimes
referred to as a “smoothing” filter). The response of this filter is
approximately the same as the output network’s response, thus
allowing the audio from the two filters to be compared in the
envelope error circuit LED board A32. Operation amplifier U11
isolates the filter output from any load variations.
K.3.7.1 Big Step Sync Circuit D/A Converter (U22)
K.3.8.3 Grounds A, AA, B and Chassis
A digital to analog converter is used to convert the bits of the
digital audio signal back into an analog signal. Switch S2 determines the number of bits that go into the D/A. Section A of S2
is between pins 1 and 4. Section B of S2 is between pins 2 and
3. Section A and B are open for DX25 operation so the 6 MSB’s
go to the D/A. Section A of S2 is closed in the DX50 operation
so the 7 MSB’s go to the D/A.
There are four grounds being used on this board. Ground A is
used in the digital signal sections. Ground B is used in the analog
signal sections. Ground AA is used in the reconstructed audio
section. Chassis ground is used where the two RF samples
sections. Ground A and ground B are connected through JP1 as
instructed on the data sheet for the AD1671. Ground A and
ground AA are connected through JP2. Chassis ground is connected to the transmitter chassis through mounting hole 2 by
using JP3.
The D/A converter output, at U22 pin 4, is a current level which
goes into R35 and produces a 0 to -1 Volt signal.
Care must be used when connecting test equipment to avoid
ground loops or other ground connections through test equip03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
K-3
ment which can introduce noise and cause errors in measurement.
100% modulation. At lower power levels and/or lower modulation levels, these analog signal amplitudes will be smaller.
K.3.8.4 Voltage Regulators (U2, U16, U18, U19, U20, U21, Q1)
K.5.1 Symptom: ColorStat™ panel CONVERSION
Four regulated voltages are provided by on-board regulators. U2
is a 7815 which converts 22 V to 15 V. U18 is a 7915 which
converts -22 V to -15 V. U21 is a 7905 which converts -15 V to
- 5 V which is used by A/D chip U1.
U16 is a LT1123 and Q1 is a MJE1123 transistor. These two
parts combine to form a +5 V low dropout regulator. The input
voltage to this regulator can get as low as +5.5 V and it will still
maintain an output of +5 V. It can also supply 4 A of current.
U19 is a 78L05 which converts +22 V or + 8 V to +5 V. Two
voltages drive this regulator in case one of them fails. This +5 V
supply is used by U20, an LM339 quad comparator chip that
monitors the regulated voltages. If the +15 V fails the signal +15
FAULT-L goes from +22 V to 0 V. If the -15V fails the signal
-15 FAULT-L goes from -7 V to -20 V. If the +5 V fails the
signal+5 FAULT-L goes from +5 V to 0 V.
K.4 Maintenance
K.4.1 Printed Circuit board Maintenance
Refer to section 5, Maintenance, in this technical manual for
general printed circuit board maintenance procedures.
ERROR Indicator is RED, transmitter operates normally.
If the transmitter operates normally, but there is a CONVERSION ERROR on the LED Board, the problem is in the indicator
circuits. Check DS1 on the Analog to Digital Converter. If the
ColorStat™ panel “Conversion Error” indicator is RED but
A34DS1 is GREEN, measure the output of U12-4.
1. If you measure a logic LOW, the problem is in the
indicator circuits on the LED Board. Refer to SECTION Q, LED Board, Troubleshooting.
2. If you measure a logic HIGH, replace U12.
NOTE
The “Conversion Error” indicator DS1 on the Analog to Digital
Converter will indicate RED whenever there is no RF drive, for
example, when the transmitter is “OFF.” The ColorStat™ panel
CONVERSION ERROR LED will still indicate GREEN because LED Board logic inhibits the conversion error fault indicator when the transmitter is turned OFF.
K.5.2 Symptom: ColorStat™ panel CONVERSION
ERROR indicator is RED, transmitter can be
turned ON. No RF out.
K.5.2.1 Check Logic Level at TP8.
K.4.2 Adjustments
K.4.2.1 Sync Sample Phasing (S1)
Adjustment of sync sample phasing is described in the Tuning/Frequency Change procedure in section 5, Maintenance, in
this technical manual.
K.4.2.2 Clock Pulse Width Adjustment (R78)
Adjustment of his control is described in the Tuning/Frequency
Change procedure in Section 5, Maintenance, in this technical
manual
K.4.2.3 Digital to Analog Converter Bit Selection (S2)
Switch S2 determines the number of bits that go into the D/A.
Section A of S2 is between pins 1 and 4. Section B of S2 is
between pins 2 and 3. Section A and B are open for DX-10,
DX-15, & DX-25 operation so the 6 MSB’s go to the D/A.
Section A of S2 is closed in the DX-50 operation so the 7 MSB’s
go to the D/A.
K.5 Troubleshooting
Refer to Schematic 839-7855-177, in the Drawing Package. Test
Points and waveforms are provided at various signal points on
the board.
NOTE
Analog signal amplitudes (including reconstructed analog signal
amplitudes) given are for 50 kilowatt transmitter output with
K-4
a. If TP8 measures logic HIGH, measure U15-5. If it is logic
LOW, U14 is faulty.
b. If TP8 measures logic LOW, the problem is the EOC-L,
the CLK ERROR-L, or the POWER RESET-L signal. To
isolate the cause to a circuit on the Analog to Digital
Converter, check logic levels at U15-1 and U15-2, then
refer to the appropriate paragraph. If pin 1 is LOW, an
“EOC-L Fault” is present; if pin 2 is LOW, a “CLK
ERROR-L Fault” is present; if both pins are LOW, a
“POWER RESET-L Fault” is present.
K.5.2.2 CLK ERROR-L: No signal at TP6
If no TTL pulses are present at TP6, make certain that sample
frequency input is present at J3-1. A loose connector is the most
likely cause of no sample frequency input because no RF drive
would also cause an Underdrive Fault on the ColorStat™ panel.
If the sample frequency input is present at J3-1, check the
Schmitt Trigger input U12-5 and output U12-6. If there is no
signal, check for shorted CR13 or CR14, or defective Schmitt
trigger U12. If signal is present at U12-6 output but not at TP6,
U29 or other sections of U12 are defective.
K.5.2.3 CLK ERROR-L: Signal present at TP6
Check the Frequency Determined Components chart for the
proper position of P10, and calculate the frequency of the logic
signal at TP6 for your operating frequency. The frequency of the
logic signal at TP6 should be between 410 kHz and 820 kHz,
depending on transmitter frequency. Check the factory test data
sheet for the transmitter, or the Frequency Determined Components Chart, for the proper position of P10 (and therefore whether
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
the divider divides by 1 or 2). If the frequency at TP6 is wrong,
P10 is in the wrong position or U29 is faulty.
K.5.2.3.1
Troubleshooting the Frequency Divider
The Synchronous Binary Counter, U29, divides the input by four
at pin 14. In this circuit, this output is fed back to the clock input
to get the divide by 2 function.
To check operation of U29, turn the Power Amplifier stage
“OFF” by placing the PA OFF switch S5 on the Controller in the
OFF (UP) position.
Remove the jumper plug at P10, and use a dual-trace oscilloscope to observe input and outputs from U29. The output at
U29-14 should be TTL level logic pulses at one-fourth the input
frequency.
EOC-L signal at U13-4 will stay LOW. This would indicate a
fault in A/D converter IC U2.
K.5.2.5 POWER UP RESET-L FAULT
Measure the voltage at U12-13. There should be a +5 VDC signal
present when the Low Voltage is ON. If there is no +5 VDC
signal and the +5 VDC supply at TP15 measures correctly,
capacitor C41 may be faulty. If there is a +5 VDC signal at
U12-13, but TP1 is logic LOW, replace U12.
K.6 Technical Assistance
See Technical Assistance clause on back of title page.
K.5.2.4 EOC-L FAULT
Use a dual trace oscilloscope to compare timing of signals at TP3
and TP5. If the EOC status output of U2 at TP5 is still HIGH
when the next START CONVERT pulse at TP3 occurs the
03/16/2009
K.7 Replaceable Parts Service
See Replaceable Parts Service clause on back of title page.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
K-5
K-6
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section L
Modulation Encoder (A36)
L.1 Introduction
This section describes the modulation encoder board, and includes a circuit description and troubleshooting information.
The modulation encoder board accepts the 12-bit digital audio
signal and encodes it to provide turn-on/turn-off signals for the
48 PA modules. The board also has data latches for both the
digital audio input and the encoded digital outputs, cable interlock circuits, PA turn-off “or” gates, and cable interlock and PA
turn off indicator LED’s and logic drivers.
The modulation encoder board is located in the non-interlocked
compartment, on the left side.
The programmable low-power PROM’s used as Read Only
Memories are permanently programmed at the factory. Programming opens internal fuse links in the PROM IC’s.
L.3 Circuit Descriptions
Circuit descriptions refer to the Modulation Encoder schematic
diagram (drawing 839-6208-088, sheets 1 through 4).
L.3.1 SUPPLY VOLTAGES AND POWER SUP-
PLY INPUTS
Refer to Sheet 1 of the Schematic diagram 839-6208-088.
L.3.1.1 +5 VOLT SUPPLY
L.2 Principles of Operation
L.2.1 Modulation Encoding: Explanation and Exam-
ple
The digital audio signal consists of a stream of 12-bit digital
“words.” The 12 bits are referred to as B1 through B12, where
B1 is the MSB (Most Significant Bit) and B12 is the LSB (Least
Significant Bit). Each word can be written in binary form, with
the MSB first and the LSB last, for example, “011010 001101.”
Each of the LAST six bits (“001101" in this example) turns a
Binary Module on or off. In this case, the 1/2 step and 1/4 step
are OFF, and the 1/8 and 1/16 steps are ON. Bit 11 (1/32 step)
is OFF, and Bit 12 (1/64 step) is ON.
The first six bits (“011010" in this example) control 42 “Big
Step” PA modules, the six binary bits must be encoded first. For
the first “Big Step,” only one PA module is turned on; for the
second “Big Step,” the first module remains ON and a second
module also turns on, and so on. (If you convert the first six
binary bits to a decimal number, you can determine the number
of PA modules that are “on”; in the example, Binary 011010
equals decimal 26, so that the first 26 “Big Step” modules are
“ON.”
The six most significant bits can provide up to 63 steps. In the
DX-10, however, only 42 “Big Steps” are used. An example may
help:
L.2.2 Modulation Encoding: Read Only Memories
“Encoding” uses 256 word by 8 bit ROM’s (Read Only Memories). The eight MSB’s (Most Significant Bits) of the encoded
audio are the eight data inputs of each ROM (at pins 1-5 and
17-19), and can address any of 256 memory locations in the
ROM. During factory programming of the ROM’s, an 8-bit
digital word is stored at each memory location.
When a memory location is addressed, the 8-bit digital word
stored at that location appears at the outputs of the IC (pins 6-9
and 11-14). Each bit of the digital word provides a turn-on/turnoff signal for a PA module.
03/16/2009
The modulation encoder board operates from +5 volts, from DC
Regulator A30, and from a “Modulated B-” voltage, also from
DC regulator A30. (Refer to Section M, “DC Regulator,” for a
description of the Modulated B- voltage, including its function.)
The +5 volt supply line is fused by 5 ampere fuse F1, and
capacitors C1 through C3 provide additional filtering. Transzorb
CR2 provides transient protection. Test point TP2 allows checking the +5 volts on the Modulation Encoder board. All integrated
circuits on the board operate from the +5 volt supply.
L.3.1.2 Modulated B-
The Modulated B- voltage is also fused, with F2, and transzorb
CR3 provides transient protection. Test point TP1 allows monitoring the modulated B-voltage. All modulation encoder board
PA module on/off signal outputs connect to the Modulated Bline through a resistor.
L.3.2 Circuit Descriptions: Digital Audio Data Cir-
cuits
L.3.3 Data Input Latches (U49, U50)
The 12-bit digital audio inputs from the A/D board are at J17
pins 2 through 24 (odd numbered pins are Ground). Resistive
dividers, sections of R10 and R11, parallel dividers at the A/D
board outputs. The digital audio inputs then go to inputs of Data
Latches U49 and U50.
L.3.3.1 “Binary Step” Digital Audio Circuits (U31, U60U61, U1, U2, U62)
The six LSB’s (Least Significant Bits, Bits 7 through 12) are
inputs to Latch U31. Each output of U31 goes to an OR gate, and
is OR’ed with a “CLIP” signal (discussed in a following paragraph). The six OR gate outputs go through terminals (E1
through E12), which are all jumpered in the DX-10. (In higher
power DX-series transmitters, the jumpers at E9-E10 and/or
E11-E12 will be removed.)
From the “jumpers,” each of the six LSB’s goes to a section of
DIP switch S1. S1 allows turning off individual binary modules
for troubleshooting or for emergency operation. The side of each
switch nearest the “Binary Step” PA modules goes to an in-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
L-1
verter/driver (U62, U1, U2); at this point, patch plugs P9 through
P14 also allow turning modules “ON” individually for troubleshooting, using the “Single RF Amp Momentary Test” function (shown on page 3 of the schematic diagram 839-6208-088).
Up to this point, the turn-on logic signal for each module is a
TTL level, logic HIGH signal.
Binary Step inverter/drivers U62, U1 and U2 are described in
the paragraphs on “Inverter/Drivers” following the description
of “Big Step” Digital Audio Circuits, below.
L.3.4 “Big Step” Digital Audio Circuits PA Module
Turn-On/Turn-Off Data Circuits
Most of the circuits on Sheet 1 through Sheet 3 of the Modulation
Encoder schematic diagram are repetitive. The next paragraphs
refer to a circuit on Sheet 1, but also describe circuits on sheets
1-3.
L.3.4.1 ROM’S (Read Only Memories) AND LATCHES
Digital audio bits 1-6 in the DX-10 address ROM’s U42 through
U47. (Bits 1-7 or 1-8 will be used in higher power DX-series
transmitters, so bits 7 and 8 also address the ROM’s). Each
output of the ROM’s provides a digital on/off signal for a “Big
Step” PA module.
L.3.4.2 Patch Plugs
P1 through P6 are 16-pin DIP sockets with U-shaped jumper
plugs. If a jumper plug is removed, there will be no turn-on/turnoff signal for the associated PA module, and the module will
remain off. However, a turn-on/turn-off signal can be routed to
another module to effectively substitute a failed module without
turning the transmitter off.
The total output of the DX-10 at any instant depends on HOW
MANY PA modules are turned on. The relative location of those
modules along the combiner pipe has no effect on output.
L.3.4.2.1
Example: Using Patch Plugs
Assume that the PA module for Step 6 has failed. For 10 kW
operation, Step 6 will be ON except when negative modulation
peaks exceed about -70%, and the failed step will increase
distortion slightly. Step 42 is used only on high positive modulation peaks, and can be substituted for Step 6, with in the worst
case only a slight reduction in positive peak capability will result.
This module substitution can be done, on the modulation encoder
board, without turning the transmitter off or physically exchanging modules, as follows:
a. Remove the U-shaped jumpers for Steps 6 and 42 (at
P4-11,12 and P6-3,4). Step numbers are also shown on the
Modulation Encoder board, next to the patch sockets. With
the jumpers removed, steps 6 and 42 remain OFF.
b. Connect a jumper from the “Latch Output” for Step 6 to
the “turn-on/turn off inverter input” for Step 42 (from
P4-11 to P6-4) Also, move the CLIP plug to P6-3, because
Step 42 is now the first UNUSED modulator output. Now,
whenever Step 6 is required to be ON, the module in the
“step 42" position will turn on, substituting for the faulty
Step 6.
L-2
c. The DX-10 can now be operated safely, and with normal
performance, with one or more “module substitutions”
using patches on the modulation encoder board, until the
next normal maintenance period.
L.3.4.2.2
Using Patch Plugs for Troubleshooting
Patch plugs can also be used for troubleshooting. By removing
the U-shaped jumper for a PA module, that module can be held
OFF. One (or two) modules can be turned on for a “single
amplifier” test by patching from P8 pins 1 and/or 2 and depressing S2 to put a simulated logic “HIGH” signal at the inverter/driver input.
L.3.5 Inverter/Drivers
Dual (“Two phase”) “MOS Clock Drivers” are used as inverter/drivers drivers, to provide the turn-on/turn-off inputs to
the PA. There is one driver for each PA module. These drivers
have very high-speed operation and can also drive large capacitive loads, including stray capacitance in PA module control
circuit input capacitance.
Referring to the Schematic Diagram, the output at pin 2 of Latch
U35 provides the turn-on/turn-off signal for Step 1, through
P4-1,2. When the signal is logic HIGH at this point, the Step 1
PA module will be turned ON.
L.3.5.1 Inverter/Driver Input
The Latch’s output goes to inverter/driver U3A’s input, at pin 2,
through isolating resistor R117 (pins 1-2). Pull-down resistor
R132 (pins 1-2) holds U3A’s input LOW if the jumper at P1-1,2
is removed, and capacitor C117 bypasses high-frequency components around R117 to improve the pulse rise and fall times at
U3A input.
L.3.5.2 Inverter/Driver Output
Refer to the schematic diagram, or to the Simplified Inverter/Driver Output circuit diagram (Figure L-1).
The output circuits of the DS0056 drivers used have two internal
transistors, one to the IC’s V+ terminal and one to the Vterminal. Only one transistor is turned on at a time, so that the
output is essentially either at V+ or V-.
The driver’s output goes to a voltage divider, made up of a
resistor from the driver output (with a paralleled “speed-up”
capacitor to improve pulse rise and fall times) and a second
resistor to the modulated B- supply. The junction of the resistors
is the PA module turn-on/turn-off control circuit input. (A logic
HIGH signal at this point turns the PA module OFF and a Logic
LOW signal turns the module ON).
Refer to (b) and (c) for equivalent output circuits. The control
voltages to the PA module depend on the instantaneous modulated B- voltage.
L.3.5.3 Modulated B-
As the PA module’s turn-on/turn-off control voltages change,
the PA’s turn-on and turn-off times will also change.
Turn-on/turn-off times also depend on the load on the modules,
that is, on the total number of modules turned on (and on the
modulation level at that moment). If one module turns on faster
than another turns off, a “spike” or “glitch” will result. Minimiz-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure L-1
Inverter/Driver output circuit simplified diagram.
ing these “glitches” by proper adjustment of modulated B- will
minimize spurious signal outputs from the transmitter.
outputs go to zero, turning off all PA modules; therefore, the
DATA CLEAR signal is also called a PA TURN-OFF signal.
Adjustment of Modulated B- is frequency dependent, and is
described in the Tuning/Frequency Change procedure in Section
5, Maintenance, in this technical manual.
The PA Turn Off (or Data Clear) input is at J17 pin 28. (Again,
refer to Sheet 1 of the Modulation Encoder schematic diagram.)
L.3.6 Data Strobe Signal Circuit: Data Latch
“Clock” Inputs
A DATA STROBE logic signal from the A/D (Analog to Digital)
Converter board “strobes” or “clocks” the latches. The DATA
STROBE input is at J17 pin 26 (refer to Sheet 1 of the Modulation Encoder Schematic diagram). Resistors R11 (pins 10 to 6)
and R11 (pins 6 to 1) form a voltage divider, or pull-up and
pull-down resistor at the input; these parallel a similar divider at
the output of the A/D Converter board. This DATA STROBE
line is pulled to ground by the inverter/driver on the A/D board
when the Data Strobe-L (TTL logic LOW) pulse is present.
Each latch is CLOCKED by a low-to-high transition, so the
DATA STROBE pulse must be inverted. Inverter/driver U57F
provides the low-to-high transition at the beginning of the Data
Strobe pulse to drive all latches on the Modulation Encoder
board. Test point TP3 allows observing the Data Strobe pulses.
Each latch is an Octal D-type flip-flop. The “low-to-high”
TRANSITION at the leading edge of each Data Strobe pulse
from U57F causes each latch flip-flop’s output to change to the
same logic state as its input. All latch outputs will then remain
in that logic state until the next Data Strobe pulse (or until a
DATA CLEAR, logic LOW signal, appears at the latch CLEAR
inputs).
On the Schematic Diagram, note that the Data Strobe line also
goes to sheets 2 and 3.
L.3.7 PA Turn-Off (“Data Clear”) Input
Each digital data Latch (see the paragraph above) also has a
CLEAR input. When the CLEAR input is logic LOW, all latch
03/16/2009
Buffer/driver U59B drives the CLEAR inputs of all latches on
the Modulation Encoder board. Test point TP4 provides a convenient point for observing the Data Clear pulse. (Buffer/driver
U59B has an open-collector output, which is paralleled with
other open-collector buffer/driver outputs, shown on sheet 4 of
the schematic diagram; PA Turn-Off circuits are described further, later in this section).
L.3.8 “Clip” Function (“Clip-H” and “Clip-L” Sig-
nals)
“Clip” Function: Description. When ALL “Binary Step” and
“Big Step” modules are turned on, and the Digital Audio signal
increases still more (which would require yet another module to
turn on) the logic “HIGH” turn-on signal for that module is
returned through a “patch cord,” P15, to the “Binary Step”
circuits and holds them all ON (see sheets 1 and 3 of the
schematic).
L.3.8.1 “Clip” Function: What Happens if the Clip-L Patch
(P15) is not Connected?
As the analog input signal to the A/D converter increases, the
A/D output consists of larger digital audio “words.” When a “Big
Step” turns on, all “Binary Steps” turn off, then as the digital
audio words continue to become larger the “Binary Steps” begin
turning on in a binary sequence to increase the transmitter’s rf
output in small increments. When ALL “Binary Steps” are ON,
the next “Big Step” turns on and all “Binary Steps” turn off again.
When ALL “Big Steps” are on and all “Binary Steps” are on, the
next larger digital audio “word” provides a turn-on signal for a
“Big Step” that does not exist. All “Binary Steps” turn off,
however, so that the transmitter’s rf output suddenly drops by
888-2247-006
WARNING: Disconnect primary power prior to servicing.
L-3
almost one “Big Step” (it drops by 63/64 of a “Big Step”), then
begins increasing as the “Binary Steps” turn on again.
tion on the Status Panel and at DS2 on the Modulation Encoder
board, when:
The result, then, is that if the audio input signal is large enough
to cause a positive modulation peak that should “clip,” instead
of “clipping” as a flat-topped peak a “sawtooth” which is 63/64
of a “Big Step” in amplitude appears instead. This would result
in an undesired audible signal. During normal operation, this
condition should not occur (if the “clip” function did not exist,
it would occur at positive modulation levels well over +125%).
a. Any of the 16 interconnecting cables between the Modulation Encoder board (A32) and PA Combiner/Motherboards (A18, A19, A20) are not in place, or
b. Any PA rf amplifier modules are not in place.
c. Power cable from DC Regulator to Modulation Encoder
is not in place.
The interconnecting cables carry PA module on/off control
signals. The interlock circuit turns all PA modules off if on/off
control signals to PA modules are missing because of cable
connectors which are not installed. Also, each PA module has a
jumper on its printed circuit board which is part of the cable
interlock circuit. If any PA module has been removed, all modules will be turned OFF by a “PA Turn-Off” logic signal generated by the cable interlock circuit.
Eliminating the “sawtooth” and providing a flat “clipped” positive peak can be done by simply holding all “Binary Steps” ON
whenever a logic HIGH signal is provided to the first unused
modulator line (the modulator line for the next “Big Step” after
the last one used in the transmitter. The “CLIP” function does
this.
L.3.9 “Clip” Circuit: Description
A “CLIP” patch cable is used to jumper P15 to the first unused
modulator line. (See Sheet 3 of the Modulation Encoder schematic diagram). When the next digital audio “word” is generated
after all “Binary Steps” and “Big Steps” are on, this line will go
HIGH (“CLIP-H” signal).
The “CLIP-H” signal goes to inverter U57A, pin 1 (see Sheet 1
of the Schematic diagram). The inverted signal is buffered by
buffer/driver U59C, to become the “CLIP-L” signal at TP5. The
open-collector output of U59C is pulled HIGH by a section of
R11 when the buffer/driver’s input is HIGH, and LOW by U59C
when the input is LOW.
This signal is inverted again by U53D. The output of U53D, at
pin 8, is a logic HIGH signal (when the “CLIP-H” is present at
P15) to one input of each of 6 OR gates in the “Binary Step” data
lines. This logic HIGH input holds all OR gate outputs HIGH,
and holds all “Binary Steps” ON, as long as the “CLIP” signal
is present.
NOTE
If one or more PA modules is taken out of service by patching on
the modulation encoder board, the “CLIP-H” patch, P15, will
also need to be moved. Refer to section 4 of this technical manual, “Emergency Operating Procedures,” for additional information.
L.3.10 Single RF Amp Momentary Test: Pushbut-
ton Switch S2
Sheet 3 of the Modulation Encoder schematic diagram shows
this circuit. The circuit consists of a pushbutton switch, which
connects pins 1 and 2 of patch connector P8 to +5 volts through
a resistance, to provide a logic HIGH signal.
When any U-shaped jumper is removed from the patch plug for
a “Big Step,” and a patch cable is then connected between the
“Output” side of the patch to P8-1 or 2, the “Momentary Test”
pushbutton can depressed to turn that module on.
L.3.11 RF Amplifier Cable Connector Interlock Cir-
cuit
The cable interlock circuit turns all PA modules OFF and provides a red “Modulation Encoder Cable Interlock Fault” indicaL-4
L.3.11.1 Cable Interlock, Description
Each of 16 cables from the Modulator Encoder board to the PA
module carries turn on-turn off control signals for four PA
modules. There is a separate interlock for each cable and the PA
modules it controls. Each interlock is a series circuit from a
pull-up resistor on the Modulation Encoder board, through the
cable, PA combiner/motherboard, all four PA modules, then
back through the cable to a ground on the Modulation Encoder
board. Figure L-2 is a simplified diagram showing one series
circuit. The figure also lists schematics needed to trace an
interlock circuit.
Cable Interlock Logic on the Modulation Encoder Board
Refer to page 4 of the Modulation Encoder Schematic or to
simplified diagram Figure L-2.
Each of the 16 interlock circuits includes a logic inverter, with a
pull-up resistor to +5 volts at its input (inverters are sections of
U51, U52, and U53). If the interlock circuit is complete, the
inverter input is pulled to ground through the interlock chain. If
a cable connector is off or any PA module in the chain is missing,
the inverter’s input is pulled high (to +5 volts), through a section
of R141, R142, or R143.
The 16 inputs are OR’ed together, first in two groups of 8 by U63
and U64, then the groups are OR’ed by U55B. The “INTERLOCK ERROR” signal at U55B’s output (pin 4) is logic LOW
if one or more interlock chains is not complete, that is, LOW if
there is an Interlock Error.
The output of U55B drives “Interlock Error” indicator circuits,
and also provides an input to “PA Turn Off” gate U56C. Interlock Error Indicator circuits and PA Turn Off circuits are described in following paragraphs.
L.3.12 Cable Interlock Indicators
Inverter U57E provides a “Cable Interlock-High” logic signal to
TP6 and to LED Board A32 when there is an Interlock Error. An
indicator driver circuit on the LED board drives the bicolor LED
“Cable Interlock” signal on the transmitter’s Status Panel. The
“Cable Interlock” signal is also available at the External Interface.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure L-2
Modulation Encoder board, Cable Interlock circuit simplified schematic.
On the modulation encoder board, LED indicators DS1 (red) and
DS2 (green) provide a RED indication if an interlock fault
(“error”) exists, or GREEN if all interlock chains are complete.
L.3.12.1 “INTLK OFF” (“ERROR”) Indication
These indicators are driven by buffer/driver U59F. When there
is an “Interlock Error,” the input and output of U59F are LOW,
and current flow through R170 and DS1 illuminates red LED
DS1. Diode CR4 also conducts through R171, pulling the junction of R171-CR4-CR5 LOW so that no current flows through
green LED, DS2. Diode CR5 ensures that DS2 will not conduct
even if U59’s output is not pulled down to zero volts.
L.3.12.2 “INTLK ON” Indication
When there is no “Interlock Error,” the input and output of U59F
are both HIGH. DS1 and CR4 do not conduct, and current flows
through R171, CR5, and DS2.
L.3.13 “PA Turn Off” Logic
PA Turn Off logic generates a logic LOW “DATA CLEAR” (PA
Turn-Off) signal which CLEARS all data latches on the Modulation Encoder board, so that their outputs all go LOW. The
LOW outputs turn off all PA modules.
Inputs to PA Turn Off logic on the Modulation Encoder board
include:
a. “Cable Interlock Error,” from a circuit on the Modulation
Encoder board.
b. “Power-Up Reset,” from a circuit on the Modulation Encoder board.
03/16/2009
c. “PA Turn-Off” signal, from fault and overload circuits on
LED Board A32.
“HIGH SPEED” Inputs:
a. “PA Turn Off” signal from Output Monitor A27 (when a
VSWR occurs).
b. “Data Clear” signal from A/D Converter Board A24 (also
called “PA Turn-Off”).
L.3.13.1 Circuit Description
Refer to Sheet 4 of the Modulation Encoder Schematic Diagram
for the following discussion. Figure L-3 and L-4 are simplified
diagrams of PA turn-off logic.
PA Turn-off Logic effectively consists of “OR” gates, so that
any of the input signals listed above will produce the logic LOW
“PA Turn-Off” signal to the CLEAR inputs of all Data Latches
on the Modulation Encoder board. L-87. Gate U56C’s output
(pin 8) goes LOW if one or more inputs goes LOW. That is, the
gate’s output goes LOW if the “Cable Interlock Fault” at pin 11
goes LOW OR “power-up reset” at pin 10 goes LOW OR “PA
Turn Off” from the LED board goes LOW.
Three open-collector buffer/drivers make up a second OR gate,
as shown in Figure L-4. Inputs are the Data Clear from the A/D
converter (to U59B, shown on Sheet 1 of the schematic); the PA
Turn-Off from VSWR detectors on the Output Monitor board
(to U59A), and the output of “OR” gate U56C (to U59D).
If one or more of these inputs go LOW, the “PA Turn Off” line
to latch “CLEAR” inputs goes LOW. Because there are fewer
888-2247-006
WARNING: Disconnect primary power prior to servicing.
L-5
Figure L-3
Modulation Encoder board, PA Turn-OFF logic simplified diagram.
Figure L-4
Parallel Open-Collector outputs as an “OR” function
(If U59A OR U59D).
L-6
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
logic elements between these inputs and the “CLEAR” inputs,
these inputs turn the PA off more quickly.
L.3.13.2 PA Turn-Off Indicators
LED’s DS3 (Red, “PA OFF”) and DS4 (Green, “PA ON”)
indicate the status of the “PA Turn Off” logic signal to the latch
“Clear” inputs. Buffer/driver U59E drives the LED’s. Circuit
operation is the same as the “Cable Interlock Indicators” circuit
already described.
L.3.14 Power-Up Reset (U57D, U57B)
The power-up reset holds the PA off for approximately 20
milliseconds during power-up, to allow all supply voltages to
reach normal values. (This time will vary because of component
tolerances).
When +5 volts initially comes on, inverting Schmitt Trigger
U57D’s input is zero (LOW) and its output is HIGH, so that the
second inverter’s output (U57B pin 4) is LOW and holds the
PA’s OFF.
When the +5 volt supply comes on, capacitor C4 begins charging
through R12, so that the voltage across C4 begins increasing.
When the voltage across C4 goes above the threshold of Schmitt
Trigger U57D (at pin 9), the output of the Schmitt Trigger goes
LOW, the output of the second inverter at U57B pin 4 goes
HIGH. If no other “PA OFF” inputs are present, the “Data
Clear-L” signal is removed from latch inputs allowing the PA
modules to turn ON according the the Modulation Encoder’s
outputs.
L.5.2 Troubleshooting Suggestions
Refer to Section 5, Maintenance, for information on using FlexPatch™ for troubleshooting. Faulty latches and other digital IC’s
can be identified using a logic probe to check inputs and outputs.
L.5.3 Symptom:
Red “PA OFF” Indicator A36DS1 (on the Board) Illuminated
L.5.4 Troubleshooting Suggestions
Check the Status Panel for other indications. Most causes of a
“PA OFF” indication will also cause a RED indication on the
Status Panel. Also, check for a RED “Cable Interlock OFF”
indication on this board (DS1); that would indicate a Cable
Interlock fault, and would also cause a RED “Modulation Encoder: Cable Interlock” indication on the Status Panel.
If there is no other indication, you can check the logic inputs to
PA Turn-Off gates to isolate the source of the incorrect logic
signal, then trace back to its cause (which may be on another
board). (Refer to the simplified diagram of PA Turn-Off logic,
Figure L-3, and to the Schematic Diagram for PA Turn-off
logic).
Most causes of “PA Off” indications on the modulation encoder
board will be traced back to “PA Off” signals from other printed
circuit boards. Failure of logic gates, inverters, or drivers can
also cause a “PA Off” indication, and a logic probe or a voltmeter
can be used to check inputs and outputs of gates, inverters, or
drivers for HIGH and LOW logic level signals.
L.5.5 Symptom:
Red “INTLK OFF” Indication on the Modulation Encoder Board
L.4 Maintenance
L.4.1 Printed Circuit Board Maintenance
Refer to Section 5, “Maintenance,” in this technical manual for
general printed circuit board maintenance procedures.
L.5.6 Possible Causes:
PA RF Amplifier module removed or not properly inserted in
socket Check PA modules to make certain that all are installed
and fully inserted in their sockets.
L.4.2 Adjustments
There are no adjustments on the modulation encoder board.
Cable From Modulation Encoder To A Combiner/Motherboard
Is Not Connected, or Connector Plug Loose in Socket. Check
cable connectors to determine that all are plugged in and properly
seated in the printed circuit board sockets.
L.4.3 “CLIP” Patch P15.
A patch cable should be installed from P15 to the jumper plug
for the first unused modulator line (use the side of the jumper
plug going to the inverting drivers, NOT the side from the latch
outputs. When ALL PA modules are in use in the DX-10, the
proper jumper plug position is P6 pin 5 for Module 43. This
position will change if one or more modules has been patched
out of service.
Printed Circuit Board Fault, or Connector Damage. These are
unlikely, but careful visual inspection could show a printed
circuit board fault (short, damaged PC board trace, poor solder
joint) or a damaged connector. It may be faster, if a logic probe
is available, to trace back through “Cable Fault” NOR gates U63
and U64 to find the faulty Interlock line or lines and isolate the
cable or section of a PC board.
L.5 Troubleshooting the Modulation En-
coder Board
L.5.1 Symptom:
Suspected Faulty Modulation Encoding
03/16/2009
L.5.7 Additional Troubleshooting Suggestions:
If neither of these locate the cause, and visual inspection does
not show any other cause, you can use a logic probe or voltmeter
to check logic levels at outputs of the Cable Interlock “OR” gates
(U63 and U64). A logic HIGH output from either gate indicates
that one or more inputs are LOW because of an incomplete Cable
Interlock circuit, or possibly a gate or driver failure. If either U83
or U84 output is HIGH, one or more of the gate’s inputs will be
LOW. When you locate the LOW input or inputs, the input of
888-2247-006
WARNING: Disconnect primary power prior to servicing.
L-7
the inverter driving it will be HIGH, and you can then refer to
the Modulation Encoder Schematic, Overall Schematic, and
L-8
Binary and Main Combiner/Motherboard Schematics as required to find the cause of the open interlock chain.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section M
DC Regulator (A30)
M.1 Introduction
This section describes the DC Regulator board, and includes a
description and troubleshooting information. The UC3834 integrated circuit voltage regulators used on the DC Regulator board
are also used on other boards in the DX-10; this section describes
all positive and negative voltage regulator circuits using this
integrated circuit.
The DC Regulator Board supplies +5 volts (regulated) and the
modulated B-voltage for the Modulation Encoder. The DC regulator includes contactor drive circuits for high voltage supply
step start contactors K1 and K2. Part of the interlock status circuit
is also located on the DC Regulator board.
The DC Regulator board, A30, is located in the non-interlocked
compartment, on the right side wall.
M.2 Principles of Operation
The voltage regulator circuits will be described first, including
a description of the linear regulator integrated circuit, then the
contactor driver and status interlock circuits will be described.
M.2.1 Circuit Grounds on the DC Regulator Board
Grounds for the +5 volt and Modulated B- supplies are kept
separate on the board. On the DC Regulator Schematic Diagram
the grounds are referenced as “A” and “B.” The grounds are
brought separately to the cabinet ground at the low voltage power
supply. Grounds are carefully controlled in the DX-10 to minimize ground loops and ac and rf noise.
M.2.2 UC3834 Integrated Circuit Linear Regulator
On the DC Regulator board, two UC3834 regulators are used,
one in the +5 volt supply and the other in the “Modulated B-”
supply.
M.2.3 OTHER SUPPLIES USING THE UC3834
This IC is also used in on-board regulated supplies on other
printed circuit boards in the DX-10. Additional regulated supplies using this IC are:
a. Analog to Digital Converter, A34:
1. -15 volt supply.
2. +15 volt supply.
3. +5 volt supply.
b. Analog Input Board, A35:
1. -15 volt supply.
2. +15 volt supply.
c. Output Monitor, A27:
1. -5 volt supply.
2. +5 volt supply.
d. Controller, A38 (Controller supply voltages are also used
on LED Board, A32):
1. +5 volt supply.
2. +15 volt supply.
3. -15 volt supply.
M.2.4 Linear Regulator IC Description
The UC3834 integrated circuit voltage regulator can be used for
either positive or negative regulated supplies. Figure M-1 is a
Figure M-1
Block diagram, UC3834 Linear Regulator.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
M-1
block diagram. An external pass transistor is used to increase
current capability. The integrated circuit has internal reference
voltages, internal fault monitoring, and a “Fault Alert” open-collector output for external logic and indicator circuits. The Fault
Monitoring circuit also provides a Crowbar Gate output. An
external compensation network at pin 14 is required to ensure
regulator stability. The IC’s current sensing feature is not used
in any supply in the DX-10, and the Current Sense input terminals (IC pins 6 and 7) are simply shorted together.
M.2.5 Regulator Circuit Operation
The basic regulator is conventional, and consists of the internal
voltage reference which is compared with a sample of the supply
output voltage by the error amplifier. Figure M-2 (a) shows a
basic positive regulator, and Figure M-2 (b) shows a basic
negative regulator. The error amplifier output is the input to a
driver amplifier in the IC, with internal overcurrent protection
for the driver amplifier. The IC’s internal driver amplifier provides base current for the external series pass transistor, at the
“Driver Sink” for positive supplies, or at the “Driver Source” for
negative supplies.
If the supply output voltage increases, the regulator IC decreases
base current to the external series pass transistor, reducing the
output voltage; if the supply output voltage decreases, the regulator IC increases base current to the external series pass transistor, increasing the output voltage.
M.2.5.1 Regulator IC: Fault Logic
Refer to Figure M-1, the regulator IC block diagram again. The
fault monitoring circuit senses both undervoltage and overvoltage conditions. Voltage sensing windows are +/-10% for positive supplies and +/-7.5% for negative supplies. Internal fault
logic activates the Fault Alert (turning on the internal transistor
and pulling pin 10 to the regulator IC’s internal ground at pin 5,
which is the “V(in)-” terminal. When there is no fault, the “Fault
Alert” output is an open collector, and if an out-of-tolerance
condition exists, pin 10 is an active low.
A “fault delay” capacitor from pin 11 to ground provides a delay
to prevent a “Fault Alert” when transient overvoltage or under-
voltage conditions occur. The “Fault Alert” will be generated
only when the fault is sustained for a delay time, which is
approximately (47 ms/uf) where “uf” is the capacitance in microfarads from pin 11 to ground.
M.2.5.2 Crowbar
A sustained overvoltage condition also activates a crowbar output at pin 16. The most likely cause of an overvoltage condition
at the supply output is a shorted pass transistor. The Crowbar
Output turns on an external Triac crowbar, shorting the supply
output to ground and blowing the fuse at the supply input.
M.2.5.3 Regulator IC Thermal Shutdown
A thermal shutdown circuit pulls the Error Amplifier output low,
turning off the IC’s internal drive transistor and external pass
transistor, when junction temperatures become excessive, protecting the IC from overdissipation in the IC’s drive transistor.
The undervoltage will then cause a “fault alert” to be generated.
M.2.6 +5 Volt Regulated Supply (DC Regulator
Board)
Refer to the DC Regulator Schematic Diagram, drawing 8396208-089, for the following description. The +5 volt supply uses
regulator IC U1, series pass transistor Q1, and crowbar triac Q2.
The unregulated input is +8 volts, from the Low Voltage Power
Supply. Fuse F1 protects the low voltage power supply if the
crowbar fires and shorts the regulator output. Capacitors C2 and
C3 bypass transients and high frequency noise on the unregulated input. The unregulated input voltage can be measured at
test point TP1. The output voltage can be measured at TP3.
M.2.6.1 Basic Regulator Circuit (U1, Q1)
The output voltage is determined by the reference voltage at pin
8 (Vref) and the voltage sample divider R5 and R6. The regulator
controls the output voltage so that the reference voltage at pin 8
is equal to the voltage sample at pin 9, from divider R5-R6; the
output voltage, then, is Vout = Vref/[R6/(R5 + R6)]. The reference voltage in the positive voltage regulators is the internal +1.5
volts from pin 3.
Resistance values in the output voltage sample divider may differ
in different supplies, even though all supplies with the same
Figure M-2
Basic positive and negative voltage regulator circuits.
M-2
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
output voltage have the same divider ratio. The resistances used
depend on the load impedance on the supply, and must not be
changed; unstable operation could result. Similarly, the compensation network resistance and capacitance (at pin 14) must not
be changed. Don’t substitute other component values.
The base of series pass transistor Q1 is driven by the “sink”
output of the IC, at pin 12. The “Source” at pin 13 goes to ground
through an “emitter resistor,” R3. This resistor shares series pass
transistor base-drive power with the IC’s internal drive transistor, allowing cooler, more reliable operation of the IC. Different
supplies in the DX-10 use different values of resistance at this
point, determined during design of each supply.
M.2.6.2 Turn-On Circuit
The +5 volt supply includes a turn-on circuit, consisting of R2
and CR1 through CR3. Diodes CR2 and CR3 provide a “reference voltage” of about +1.2 volts (the junction drop across the
two diodes when they are conducting). When the internal reference voltage has not come on during turn-on, Schottky diode
CR1 is forward biased, providing a voltage of slightly less than
1 volt at pin 8, the error amplifier non-inverting input. When the
internal reference voltage increases, diode CR1 will be reverse
biased and the error amplifier reference voltage will be the +1.5
volts from the regulator IC’s internal reference.
M.2.6.3 Crowbar (Q2)
The crowbar operates when a sustained overvoltage condition
occurs at the regulated output. The most likely cause of an
overvoltage condition is a shorted pass transistor, so that when
the crowbar triac fires the output is shorted and fuse F1 blows.
Normally, the “Crowbar Gate” output is an open circuit. When
an overvoltage condition remains longer than the “delay time”
set by C4 (at pin 11), the “Crowbar Gate” output at pin 16 goes
toward “V(in)+,” firing the triac. Resistors R7 through R10 limit
peak current through the triac and fuse.
M.2.6.4 Other Regulator Circuit Components
Additional components include:
a. Supply voltage for the IC’s internal circuits: Resistor R1
to pin 1 is the supply voltage for the regulator’s internal
circuits, and current sense inputs at pins 6 and 7 are tied to
pin 1. This supply voltage is not fused.
b. Feedback Loop Compensation: Capacitor C1, from pins
14 and 15 to ground, is a feedback loop compensation
capacitor.
c. Fault-Alert Pull-Up Resistor: Resistor R2 is a pull-up
resistor to +5 volts for the Fault Alert output.
d. Transient protection: Transient protection at the output
includes transzorb CR5 and bypass capacitors C5 and C6.
e. Reverse voltage protection: Diode CR4 across series pass
transistor Q1 provides protection if a reverse voltage is
accidentally applied at the unregulated input.
M.2.7 Other Positive Regulated Supplies
Operation of all regulated supplies using the UC3834 linear
regulator IC is similar to operation of the +5 volt supply on the
DC regulator board. Voltage sample divider resistances, com03/16/2009
pensation components, and IC driver emitter resistances depend
on supply load impedance, and will be different in different
supplies. Also, the +15 volt supplies do not have the “Start Up”
circuit used in the +5 volt supplies.
M.2.8 Modulated B- Supply
The Modulated B- supply provides a negative voltage to the
Modulation Encoder board, which varies with the transmitter’s
audio input and power level.
The effect of the modulated B- voltage is to minimize spurious
outputs by controlling PA module turn-on/turn-off times. Turnon/turn-off times depend on loading on each module, which in
turn depends on the total number of modules which are operating.
At low power levels (including negative modulation peaks), only
a few “big steps” are on, and each PA module is lightly loaded.
As additional “big steps” turn on, the loading changes considerably and the required turn-on/turn-off times also change. At
higher power levels (more modules turned on), the loading on
each module does not change nearly as rapidly when additional
modules turn on (or turn off).
To minimize spurious output, the B- voltage must be more
negative on positive peaks, but must change more slowly as the
transmitter’s instantaneous output becomes greater (and more
modules are turned on). Therefore, the B- voltage must vary in
a non-linear manner as the -(audio + dc) sample changes.
A non-linearity circuit between the -(audio + dc) input and U3’s
error amplifier reference voltage input purposely distorts the
audio input. If the incoming signal at J4-10 and the supply output
voltage at TP7 and J2-1 and 2 are compared, the resulting wave
forms will be very different. This is normal.
M.2.8.1 Approximate Modulated B- Supply Output Voltages
At an operating power of 10 kilowatts and with 100% modulation, the instantaneous Modulated B-voltage should vary between roughly -2 and -6 volts. At negative 100% modulation
peaks, the instantaneous voltage should be about -2 volts, and at
positive 100% peaks, the instantaneous voltage should be about
-6 volts. This voltage range will be less at lower operating
powers. For an operating power of 1 kilowatt, instantaneous
Modulated B-voltage should be on the order of -2 volts at -100%
peaks and -3.5 volts at +100% peaks.
There are four adjustments for the Modulated B- supply, two on
Analog to Digital Converter board A34 and two on the DC
Regulator board (A30). These adjustments are described in the
Tuning/Frequency change procedure in Section 5, “Maintenance,” in this Technical Manual.
M.2.9 Modulated B- Supply: Circuit Description
Refer to the DC Regulator Schematic Diagram, drawing 8396208-089, for the following description. The modulated Bsupply uses regulator IC U3, series pass transistor Q5, and
crowbar triac Q4.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
M-3
M.2.9.1 -(Audio + DC) Input
The “reference voltage” for the Modulated B- supply is a negative (inverted) sample of the analog audio signal and dc power
control signal, from the output of the Analog Input board (A35).
The non-linearity circuit consists of diode CR12, “Clip Adj”
potentiometer R39, diode CR10, and resistors R21, R23, and
R22. Zener diode CR7 and resistor R24 provide a regulated -1.22
volt reference for this circuit. Schottky diode CR6 is not part of
this network, but provides protection, preventing accidental
positive reference voltages.
When the -(audio + dc) input is small, corresponding to a
negative modulation peak, changes in this input voltage result in
roughly proportional changes in the reference voltage at U3 pin
9. As the -(audio + dc) input becomes more negative (that is,
greater in magnitude), it is clipped more and more heavily and
changes in the input result in much smaller changes in the
reference voltage at U3 pin 9, and in the Modulated B- supply
output voltage.
M.2.9.2 Modulated B- Supply Regulator Circuit
The output voltage from the regulator circuit depends on the
reference voltage and the setting of adjustable resistor R38 in the
output voltage sample divider. The error amplifier in U3 compares the reference voltage, at pin 9, and a sample of the supply
output voltage, at pin 8. The regulator IC controls the base
current into series pass transistor Q5 to adjust the output voltage,
so that the differential voltage between pin 9 and pin 8 is
essentially zero.
The unregulated input is -8 volts, from the low voltage power
supply. Fuse F3 protects the low voltage power supply if the
crowbar fires and shorts the regulator output. Capacitors C12, a
disc ceramic, and C13, a tantalum capacitor, provide high and
low frequency bypassing. The unregulated input voltage can be
measured at test point TP5. The negative output voltage, at test
point TP7 and J2 pins 1 and 2, depends on transmitter power and
instantaneous modulation level.
Supply voltages for the internal circuitry in the regulator IC are
+8 volts, through R36 to pin 1 (V+) and -8 volts, through R25 to
pin 5 (V-). Pins 6 and 7, the unused current sense inputs, are both
connected to pin 5 as well.
Triac Q4 is the “Crowbar,” which is triggered by a signal from
pin 16 if the regulator circuit is unable to control the output
voltage so that the voltage from sample divider R27-R20-R38,
at IC pin 8, is more than 7.5% greater than the reference voltage
at IC pin 9. Resistors R28-R29-R30-R31 limit surge current
when the crowbar is triggered.
The compensation network is R37 and C11, from pins 14-15 to
V-. The “fault delay” is determined by capacitor C10, from pin
11 to the unregulated input. Diode CR8, across series pass
transistor Q5, protects the regulator circuit if reverse voltage is
accidentally applied at the unregulated input. Transzorb CR9
limits transient voltages in the supply’s output, and diode CR11
prevents forward current flow through the transzorb. Capacitors
C14 and C15 are bypass capacitors for transients.
M.2.10 Other Negative Regulated Supplies
Operation of all negative regulated supplies using the UC3834
linear regulator IC is similar to operation of the modulated Bsupply on the DC regulator board. Other negative supplies return
pin 1, “V+ IN” to ground. The -5 volt supplies include a start-up
circuit like the one used for the +5 volt supply; -15 volt supplies
do not have the start-up circuit.
Figure M-3
Simplified diagram, 24VAC source for AC contactors. Note that the 24 volt AC
circuit is isolated from ground and one side of the 24VAC circuit is at +30VDC.
M-4
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Voltage sample divider resistances, compensation components,
and IC driver emitter resistances depend on supply load impedance, and will be different in different supplies.
M.2.11 Contactor Drivers (U2, Q3, U4 and Q6)
The Contactor Driver circuits accept transmitter turn-on signals
from the Controller (A38) and drive High Voltage step-start
contactors K1 and K2. K1 and K2 have 24 volt ac coils.
M.2.11.1 High Voltage Supply Contactors
Recall that when K1 closes, 220 Vac is applied to the high
voltage transformer through resistors to limit surge currents as
the supply capacitors charge, then 1.1 seconds later K2 is energized, bypassing the surge-limiting resistors. The transmitter
turn-on/turn-off circuits are described in Section 7, System Operation, and in Section P, Controller Board.
M.2.11.2 AC Supply for K1, K2
The contactors operate from a 24 Vac supply, from half of the
transformer secondary also used for the +30 and +60 volt supplies. Refer to Figure M-3, “Simplified Diagram, 24 Vac source
for AC Contactors.” Note that both sides of the 24 Vac are
isolated from ground, and that one side of the 24 Vac circuit is
also at +30 volts dc, referenced to ground.
Three interlock status circuits pass through the DC Regulator
Board: “Door Interlocks,” “External Interlocks,” and “Interlock
String DC.” Door Interlock status and External Interlock status
are indicated on the transmitter status panel, and are also available at the external interface for remote readout.
M.2.12.1 External Interlock Status
If the External Interlock circuit is OPEN, contactor K3 de-energizes, and its contact opens. J3-13 then provides a positive dc
voltage to the Interlock Status circuits on LED Board A-32. If
the External Interlock circuit is CLOSED, K3 energizes and its
contact pulls J3-13 to ground.
M.2.12.2 Door Interlock Status
Contacts on the door interlock switches are CLOSED when the
doors are CLOSED, and OPEN when the doors are OPEN. If
either door is OPEN, then, a positive DC voltage goes to the
Interlock Status circuits on the LED board. If both doors are
closed, the Door Interlock Status line is pulled to ground.
M.2.12.3 Interlock String DC Status
Normally open contacts on External Interlock relay K3 and Door
Interlock relay K4 provide a +30 volt dc signal (referenced to
transmitter ground) when both relays are energized. This signal
is input to the interlock status logic on LED board A32.
When referring to the overall schematic, remember that the “+30
Vdc” line is also one side of the 24 Vac circuit for the contactors.
Figure M-4, “Contactor Driver, Interlock, and Interlock Status
Circuits, Simplified Diagram” shows interlock circuits and contactor drivers. The ac supply for high voltage supply contactors
K1 and K2 goes through normally open contacts on External
Interlock relay K3 and Door Interlock relay K4. If either interlock circuit is open, K3 or K4 (or both) will be de-energized,
interrupting the 24 Vac supply for relays K1 and K2 and preventing the high voltage from coming on.
The 24 Vac supply to the contactor drivers and step-start contactors is fused, by fuse F2.
M.2.11.3 Contactor Drivers
Refer to Figure M-4 or to the DC Regulator schematic diagram
839-6208-089 for the following discussion. Each contactor
driver includes an optically isolated triac driver (U2, U4) and a
triac in series with the contactor coil. Resistor-capacitor networks are used to suppress triac switching noise.
M.3 Maintenance
M.3.1 Printed Circuit Board Maintenance
Refer to Section 5, “Maintenance,” in this technical manual for
general printed circuit board maintenance procedures.
M.3.2 Adjustments
There are two adjustments on the DC regulator board, both for
the Modulated B- supply. Refer to the Tuning/Frequency
Change procedure in Section 5, “Maintenance,” for information
on making these adjustments.
M.4 Regulated Power Supply Trou-
bleshooting
When the “contactor drive” transistor in the controller conducts,
current flow through the LED in the optically isolated triac
driver, causing it to illuminate. The triac in the driver then
conducts, placing an ac voltage on the gate of the contactor driver
triac (Q3 or Q6, on the dc regulator board). The triac then turns
on, and ac current flows through the associated step-start contactor coil, energizing the contactor.
Unless a specific supply is mentioned, these symptoms and
possible causes apply to any regulated supply using the UC3834
regulator integrated circuit.
M.2.12 Interlock Status Circuit
Figure M-4 also shows the interlock status circuit on the DC
Regulator board, along with interlock switches and relay contacts which are not located on the board. The DC Regulator board
includes only resistors and interconnections for the circuit. Interlocks are shown on the Overall Schematic, and Interlock
Status logic is located on the LED board.
M.4.2.1 Temporary Overvoltage or Transient
03/16/2009
M.4.1 Fuse in Unregulated Input Line Open (F1 or
F3 on DC Regulator Board)
M.4.2 Possible Causes:
A temporary overvoltage condition at the regulator output will
fire the triac, and cause the fuse to open. If you replace the fuse
and it immediately opens again, then look for a shorted component or load.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
M-5
M.4.2.2 Shorted Transistor or Diode
A shorted Series Pass Transistor, or Shorted Diode From Pass
Transistor Emitter to Collector could be the cause. Disconnect
primary power from the transmitter before checking components. With the supply’s fuse removed, check from emitter to
collector of the pass transistor, using an ohmmeter on a low ohms
range (recall that there is a rectifier diode across the pass transistor). If you read a short, remove the pass transistor to check
the diode and transistor separately. Diode failure is unlikely,
unless a reverse voltage has been accidentally applied at the
regulator input. If the pass transistor is shorted, check the crowbar triac as well.
M.4.2.3 Shorted “Crowbar” Triac
Remove the connector from J2 to remove the low impedance
load which parallels the triac, then check the triac using a low
ohms range on the meter. Again, remember that the transzorb,
which is a type of zener diode, is in parallel with the triac, and
the transzorb will conduct in the reverse direction if much over
five volts is applied, as well as conducting in the forward
direction.
M.4.2.4 Shorted Load
An ohmmeter should be used to locate a shorted load.
M.4.3 No Output Voltage or Output Voltage Less
than about -2 Volts from Modulated B- Supply
M.4.4 Possible Causes:
M.4.4.1 Modulated B- Supply Controls Not Adjusted Properly
Refer to the Tuning/Frequency Change Procedure in Section 5,
Maintenance, for adjustment procedures.
Figure M-4
Contactor Drive, Interlock and Interlock Status circuits simplified diagram.
M-6
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
M.4.4.2 No -(Audio + DC) Signal
Check the input at J4 pin 10 for a -(Audio + DC) signal from the
Analog to Digital Converter Board.
03/16/2009
Prior to starting a troubleshooting procedure check all switches,
power cord connections, connecting cables, and power fuses.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
M-7
M-8
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section N
External Interface (A28)
N.1 Introduction
This section describes the External Interface board and includes
a troubleshooting information.
The External Interface board provides an interface between the
transmitter’s Controller and any external control or monitoring
equipment, including remote control equipment and extended
control and monitoring panels. Interface circuits on the board
provide isolation between the Controller section and any connections made at TB1 and TB2, and diodes and transzorbs (type
ICTE-5 or ICTE-15) protect the transmitter from transient voltages from external cabling and from improper voltages accidentally placed on external interface terminals.
The External Interface Board, A28, is located at the top of the
right hand side of the non-interlocked compartment. External
Interface terminal boards TB1 and TB2 are located just above
the External Interface board, and are connected to the board with
ribbon cables.
N.2 Principles of Operation
Interface circuits include opto-isolated control inputs, analog
voltage “monitor” outputs, open-collector “status” outputs, and
resistive voltage dividers for external monitoring of low-voltage
supply voltages. Terminal board TB3 provides audio input connections, and bipolar zener diodes for protection against transient voltages. Zener diode regulators on the board provide +15
volts and -15 volts to operate IC’s on the board, and three-terminal regulators provide +15 volts at 175 mA and -15 volts at 175
mA for customer use when either relay contacts or open-collector transistor outputs are used as remote control inputs. (A
customer-supplied battery or power supply can also be used, the
internal voltages are provided for convenience).
All front-panel meter readings, front-panel status indications,
and all front-panel control functions (except the Remote/Local
switch) are available at the external interface panel.
Analog voltage samples are set at 3.4 volts when normal meter
readings are present. This allows for high excursions in readings
while still remaining under the 4-volt limit of some currently
available microprocessor-based remote control equipment.
N.2.1 Schematic Diagrams
The External Interface Schematic Diagram, drawing 839-6208099, includes three sheets. Sheets 1 and 2 are schematic diagrams
of all circuits on the printed circuit board. Sheet 3 provides
application information and reference information, including
simplified diagrams of each type of interface circuit, and interface circuit connections for all terminals on customer interface
terminal boards TB1 and TB2. In addition, terminal numbers and
functions for TB1 and TB2 are silk screened on the inside of the
front door.
03/16/2009
N.2.2 Circuit Descriptions
Each TYPE of interface circuit is described in the following
paragraphs. Sheet 3 of the schematic diagram provides a summary of information for each type of interface circuit, in the
“Characteristic Key”. The “Type” for each description refers to
the designations (A, B, C, D, E, F, G) in the Characteristic Key.
Additional figures in this section also provide information on
typical applications.
N.2.3 Status Outputs (Type A)
Refer to Sheet 3 of the External Interface Schematic Diagram,
drawing 839-6208-099.
Each status output is an open-collector output. When the action
described by the name of the signal at that status output is
happening, the transistor will be turned on (saturated), providing
a current sink to ground for a positive voltage applied at that
input. All Status Output transistors return to ground. Examples
include:
a. “Lower” Indicator: When the “Lower” button on the transmitter is illuminated, the transistor between TB1 terminal
15 and ground is “on”.
b. “Low” Indicator: When the Low Power button on the
transmitter is illuminated, indicating that the transmitter is
in the low power mode, the transistor between TB1 terminal 20 and ground is “on”.
c. “Supply Current Overload” indicator: When the “Supply
Current” overload indicator on the transmitter’s Status
Panel is RED, indicating a supply current overload, the
transistor between TB2 terminal 25 and ground is “on”.
When the overload indicator on the status panel is green,
the transistor is “off” and terminal 25 is an open circuit
(unless reverse or excessive voltage is applied to the
terminal).
N.2.3.1 Status output Protection
Status outputs are protected against reverse voltage by a diode
connected between the transistor collector and ground, with the
diode’s anode at ground. This protective diode will conduct if a
negative voltage is connected at the Status Output terminal on
TB1 or TB2.
Status outputs are also protected against excessive voltage inputs
at the Status Output terminal by a diode connected between the
transistor and the +22 volt unregulated supply. If an overvoltage
at the terminal causes enough current flow through the diode, the
27 ohm resistor between the transistor collector and the terminal
board for that output will burn out.
A capacitor from the transistor to ground provides bypassing for
transient and rf currents.
Refer the notes for Characteristic Key A on sheet 3 of the
Schematic Diagram for additional information on Status Outputs, including current and voltage limitations. N-20. USING
888-2247-006
WARNING: Disconnect primary power prior to servicing.
N-1
STATUS OUTPUTS. Refer to Figure N-1 for two possible
output configurations
N.2.4 Control Inputs (Type B)
All extended control inputs (remote control inputs) are optically
isolated. Both sides of the input are isolated from ground, allowing flexibility in control input circuits which are external to the
transmitter.
For each control input, there are two terminals on TB1 or TB2,
labeled (+) and (-). Again, both terminals are isolated from
ground.
N.2.4.3 Protection
Series resistors limit current to the opto-isolator; when input
voltage is 15 volts, opto-isolator current is 40 mA. The resistor
network, a transzorb, and bypass capacitors protect the opto-isolator input from transient voltages.
Figure N-2 shows three possible control input configurations.
N.2.5 Monitor Voltage Outputs
Monitor outputs include three types of outputs, including voltage
divider outputs and monitor voltage outputs. Each type is described in following paragraphs.
Figure N-1
External Interface, typical status output circuits.
N.2.4.1 Opto-Isolator
N.2.5.1 Voltage-Divider Outputs (Type C or Type D)
The opto-isolator input is a light-emitting diode, with both sides
above ground. When current flows through the diode, illuminating it, the internal photo-transistor conducts, providing a current
sink between the output terminals; each optoisolator’s phototransistor is effectively part of a logic circuit on the Controller
board, including pull-up resistors (refer to section P, “Controller”, for additional information).
Voltage divider outputs are used to monitor the +22 volt, -22
volt, +8 volt, and -8 volt low-voltage supply outputs. Each output
circuit consists of a resistive voltage divider, with a transzorb for
overvoltage protection, and a bypass capacitor at the input. These
monitor voltage outputs appear at TB2, terminals 35 through 38,
and are all referenced to ground.
N.2.4.2 Control Input Requirements
To initiate or activate the control action for each control input, a
momentary voltage (100 milliseconds or longer) must be applied
to the control input to illuminate the opto-isolator’s internal
LED.
To prevent the transmitter control action from activating, the
voltage input to the “Control Input” terminals must be about zero
(voltage input must be between -1 and +1 volt). It is possible that
voltages greater than +1 volt could activate the control action,
because of component tolerances. Voltages less than -1 volt may
cause component damage.
Refer to Sheet 3 of the Schematic diagram, to the notes for
Characteristic Key B, for additional requirements and limitations
on control input current and voltage. Exceeding voltage or
current limitations can cause too much power dissipation in the
series resistors or damage the opto-isolator.
N-2
The output from all four voltage dividers will be 3.4 volts when
the input voltage is at it’s nominal value (+22 volts or +8 volts),
and there is no load or a high-impedance load on the voltage
divider. The monitor voltage output is nominally +3.4 volts for
the +22 volt and +8 volt supplies, and -3.4 volts for the -22 volt
and -8 volt supplies.
Any loading will reduce this sample voltage. Normally, remote
control unit calibration will compensate for loading on the
voltage divider outputs. However, if you know the load resistance and want to calculate the reduced nominal voltage, the
Thevenin equivalent voltage and source resistance for each
voltage divider output are given on sheet 3 of the schematic
diagram; if you are not familiar with Thevenin equivalent circuits, see Figure N-3.
N.2.5.2 Operational Amplifier Buffered Outputs (Type E)
Refer to “Characteristic Key: E” on sheet 3 of the schematic
diagram for a simplified schematic diagram, and to sheet 2 for
complete schematic diagrams. There are six different parameters
using this type of monitor voltage output:
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Figure N-2
External Interface, typical control input circuits.
Figure N-3
Equivalent circuits for calculation effect of circuit loading
on Monitor voltage outputs.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
N-3
a. Forward Power
b. Reflected Power
c. Supply Current
d. Supply Volts
e. RF Drive (Estimate)
f. Antenna VSWR
g. Bandpass Filter VSWR
The Forward Power, Supply Current, and Supply Volts outputs
will be nominally 3.4 volts when the transmitter is operating at
10 kW output power. These output levels are determined by
sample circuits in other parts of the transmitter.
N.2.5.3 Circuit Description
Each analog signal monitor output is buffered by a section of U4,
U5, U7 or U7 (half of U7 is not used). Each operational amplifier
is configured as a voltage follower (gain = +1). The impedance
at the op-amp output terminal is very low, so the voltage monitor’s output impedance is 2,000 ohms (determined by the two
resistors in series with the output).
A 15-volt transzorb and a bypass capacitor provide output protection. The worst-case output voltage at the interface terminal
board is therefore + 15 volts (if the op-amp fails, and it’s output
goes to either the +15 or -15 volt rail).
N.2.6 External Interlock
The external interlock terminals, TB1-1 and TB1-2, are part of
the transmitter’s interlock circuit, which operates a 24 volt AC
relay, “External Interlock” relay K3, which has a 2 volt-ampere
coil. Contacts and interconnecting wire or cables in the external
interlock circuit must be handle this ac current, and total external
interlock circuit resistance should be kept low to ensure reliable
closure of K3. See Figure M-4, in section M, “DC Regulator,”
for a drawing showing the entire interlock string.
NOTE
THE TRANSMITTER WILL NOT OPERATE IF THERE IS AN
OPEN CIRCUIT BETWEEN THE EXTERNAL INTERLOCK
TERMINALS, TB1-1 AND TB1-2.
The open-circuit voltage between the terminals is 24 volts ac.
One of the terminals is also connected to the +30 volt dc
low-voltage supply output, and is at +30 Vdc referenced to
ground.
CAUTION
THE EXTERNAL INTERLOCK CIRCUIT MUST BE ISOLATED
FROM GROUND. GROUNDING ANY PART OF THE EXTERNAL
INTERLOCK CIRCUIT ILL SHORT-CIRCUIT THE LOW-VOLTAGE
POWER SUPPLY +30 VOLT OUTPUT.
N.2.7 Audio Input
The Audio Input Terminal board, A28TB3, is located on the
External Interface printed circuit board.
TB-3, Terminals 1 and 2, are for a balanced 600-ohm audio
input. Terminal 3 is at the transmitter cabinet ground. This will
be the normal connection point for the audio input cable’s shield.
erminal 4 is an additional audio input circuit ground which is ac
coupled to cabinet ground. It will not normally be used.
N-4
A bipolar zener diode (CR30 and CR31) from each side of the
balanced audio input to ground provides overvoltage protection.
An interconnecting cable runs from A28J11 to the Analog Input
board.
Audio input levels for 100% modulation are adjustable, from -10
to +10 dBm (at 600 ohms); the adjustment is located on Analog
Input Board A35. For additional information on the audio input,
including information on matching to source impedance, refer
to Section J, Analog Input Board, and Section 2, Installation.
N.2.8 Combiner Interconnect
Two BNC coaxial connectors, J7 and J8, are provided for interconnection to the combiner control unit when the DX-10 is used
in a combined transmitter installation. The Technical Manual for
the Combiner Control unit will include information on using
these connectors.
N.2.9 PA Turn-Off and Off Control
Terminals 21 and 23 on TB1 are for a “PA TURN-OFF” connection, and TB1 terminals 33 and 35 are for “OFF CONTROL”.
Both are optically isolated control inputs, as described earlier in
this section.
N.2.9.1 PA Turn-Off
The “PA Turn Off” control input turns off all PA modules
through the modulation section of the transmitter; it does NOT
operate the High Voltage contactors or turn off the high voltage
supply!
PA Turn-Off is intended to turn the PA off briefly during antenna
pattern changes, antenna selection, or during other times when
transmitter rf output is switched.
“PA Turn-Off” MUST NOT be used for failsafe or for transmitter shut down. As soon as the PA Turn-Off control input voltage
is removed, the PA will come back on again, at the power level
determined by the High, Medium, and Low power switches and
the raise/lower controls.
N.2.9.2 Off Control
The “Off Control” control input operates in the same way as the
transmitter’s front panel “Off” switch, by de-energizing the high
voltage supply primary contactor and resetting turn-on/turn-off
control circuits.
The “Off Control” should be used any time the transmitter is to
be turned off for any reason other than a brief interruption of rf
output power during antenna switching or antenna patter change
operations.
N.2.10 External Interface Power Supplies
N.2.10.1 DC Voltages Supplied to the Board
Four dc voltages from the low voltage power supply are brought
from low voltage supply Power Distribution Board A39 to the
External Interface board. The +8 and -8 volt supplies are used
only for external monitoring outputs. The +22 and -22 volt
supplies are also used for external monitoring outputs, but in
addition are regulated to +15 and -15 volts for circuits on the
external interface board and to supply voltages required for
external interfacing.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
N.2.10.2 Zener Diode Regulated +15 and -15 Volts
Zener-diode regulated +15 volt and -15 volt supplies provide
operating voltages ONLY for operational amplifiers U4, U5, U6
and U7.
N.2.10.3 Three-Terminal Regulators
Three-terminal IC voltage regulators provide +15 VDC at up to
175 ma, and -15 VDC at up to 175 ma for external use. These
voltages are brought out at TB1-11 and 12 (TB1-10, 13 and 14
are ground connections), and can be used as convenient voltage
sources for control input circuits and for status output circuits.
These three-terminal IC voltage regulators are overcurrent protected, and their output voltages will decrease if excessive current is drawn. here are a large number of Status outputs, and if
these supplies are used, you should ensure that total current drain
cannot exceed 175 mA from either supply.
To determine whether the opto-isolator or transmitter logic is at
fault, monitor the voltage across the opto-isolator’s output terminals while activating the remote control input again. (Voltage
can be monitored either on the external interface board or at the
controller board input). If the voltage across the opto-isolator’s
output terminals drops to less than 0.5 volts, the opto-isolator is
operating properly. Refer to Section P, Controller, for information on troubleshooting the controller.
N.4.2.2 Additional Notes:
Current through the control input terminal circuit turns on an
opto-isolator, by illuminating an internal LED. A current between 40 and 70 milliamperes is required to illuminate the LED
and activate the photo transistor.
N.4.3 Symptom: No Remote Status Outputs Operate
Possible Causes:
N.4.3.1 No Supply Voltage For Status Circuits
N.3 Maintenance
Refer to Section 5, Maintenance, for information on maintaining
printed circuit boards. No other preventive maintenance is required on the External Interface board.
N.4 Troubleshooting
N.4.1 Symptom: No Remote Control Inputs Operate
Possible Causes:
N.4.1.1 Supply voltage for external inputs missing
If +15 V from TB1-11 or or -15 V from TB1-12 is used, check
for presence of this voltage. If voltage is missing, check voltage
regulator U6 for +15 volts at it’s output and U9 for -15 volts at
it’s output. If there is not output, check the +22 or -22 volt input.
If a customer-supplied battery or power supply is used, check
it’s output voltage.
N.4.1.2 Remote Control Equipment Fault
Refer to the discussion under “Some Remote Control Inputs
Operate, But One or More Do Not”, below.
N.4.2 Symptom: Some Remote Control Inputs Oper-
ate, But One or More Do Not
Possible Causes:
N.4.2.1 Faulty Opto-Isolator, Faulty Transmitter Logic, or
Faulty Remote Control Equipment
While monitoring the dc voltage between the control input
terminals on TB1 or TB2 for a faulty control input, activate the
remote control equipment. If the voltage between the terminals
is 15 volts or more, the problem is in the transmitter. If the
voltage is small, the problem is a shorted opto-isolator input or
the problem is outside the transmitter.
03/16/2009
A positive voltage through circuits external to the transmitter
must be supplied to each status output used, at the proper
terminal on TB1 or TB2. For each remote Status output, when
there is no red status indication on the transmitter status panel or
illuminated pushbutton switch, there should be a positive voltage
on the corresponding terminal on TB1 or TB2. The diode from
the status output transistor collector to +22 volts is only for
protection, and is not a supply voltage. Determine where the
supply voltage for external status circuits comes from, then
check that supply.
N.4.4 Symptom: Some Status Outputs Operate
But One or More Does Not (Fault Indication on Transmitter
Status Panel but No remote Status Indication)
N.4.4.1 Problem In Transmitter Fault And Overload Logic
Use a voltmeter or logic probe to check the logic level (input
voltage) to the status interface circuit on the External Interface
board. When a fault is present, the input at J6 should be logic
HIGH and the transistor base should be about +.6 to +.7 volts. If
the input is not logic HIGH, the problem is in transmitter fault
and overload logic. Most fault and overload logic is described in
section P, Controller Board and section Q, LED Board.
N.4.4.2 Problem Is Outside The Transmitter
Check for voltage at the corresponding terminal on external
interface terminal board TB1 or TB2. When there is a “status”
indication (red LED or illuminated pushbutton switch), the corresponding terminal should be LOW, because the transistor on
the external interface board provides a current sink to ground;
when there is no status indication, the terminal should be HIGH
(close to the external supply voltage). Further troubleshooting
depends on remote control unit or remote indicator circuits used.
N.4.5 Symptom: One or More Remote Status Indica-
tions Remain “ON” Even Though the Transmitter’s Status Indication is Off (or Green)
888-2247-006
WARNING: Disconnect primary power prior to servicing.
N-5
Possible Causes:
N.4.5.1 Problem In Transmitter Fault And Overload Logic
Use a voltmeter or logic probe to check the logic level to the
status interface circuit on the External Interface board. When the
transmitter’s “Status” indication is not on (LED is green or
pushbutton switch is illuminated), the input at J6 should be logic
LOW. If the input is logic HIGH even when the transmitter’s
corresponding status LED is green or the pushbutton switch is
not illuminated, check transmitter fault and overload logic. Most
fault and overload logic is described in section P, Controller
Board and section Q, LED Board.
N.4.5.2 Shorted Transistor On Fault And Overload Board
The status interface transistors are in DIP integrated circuit
packages; pin-outs are shown on the External Interface schematic diagram. You can check for a transistor emitter-collector
short by removing primary power from the transmitter, then
disconnecting the external lead at TB1 or TB2 and using an
N-6
ohmmeter to check for a short to the transmitter ground. A
“good” transistor should read “open”.
N.4.6 Symptom: No Monitor Outputs (Analog Sig-
nal Outputs) Operate, or All are Seriously Incorrect
Possible Causes:
N.4.6.1 No +15 Volts, or -15 Volts, or Both On External Interface Board.
Each analog voltage to the monitor output terminals is buffered
by a voltage follower. On-board zener diode regulators CR7 and
CR8 provide +15 volts and -15 volts to operate the voltage
followers. Failure of the zener diodes would result in no output
from the op amp. Failure of one zener diode would result in
incorrect output or no output.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
Section P
Controller (A38)
P.1 Introduction
This section describes Controller board circuits, and includes
circuit descriptions.
Circuits on the Controller board include turn-on and turn-off
control logic; digital power control logic for setting rf output
power; indicator lamp drivers; analog buffers for metering of rf
power, VSWR, and supply voltage; and +5V, +15V and -15V
voltage regulators which supply operating voltages for the Controller and LED boards.
In this section, circuit operation is discussed; the turn-on/turn-off
control logic sequence is also described. Section 4, “System
Theory,” also includes a shorter description, emphasizing function and logic flow rather then circuit descriptions.
The Controller board is located on the back side of the transmitter’s center front door. The Controller board is the lower board;
the LED board is located above it.
P.2 Principles of Operation
This section describes circuits on the Controller printed circuit
board. The description will be divided into functional groups of
circuits, as follows:
a. Turn-on/Turn-off Control Logic.
b. Power Control Logic.
c. “Interlock Status” Fault Logic.
d. +5B Reset Circuit.
e. Power Supplies (+5, +15, -15 volt regulators).
f. Supply Fault Logic.
g. Analog Monitor Buffer/Drivers, for Metering.
Circuit descriptions refer to the Controller board Schematic
Diagram (839-6208-100, sheets 1, 2 and 3), as well as to block
diagrams and simplified schematic diagrams in this section.
P.3 Transmitter Turn-On/Turn-Off Con-
trol Logic
The transmitter turn-on/turn-off control logic, located on the
Controller Board, provides drive signals for step-start relays K1
and K2, and also provides logic signals to inhibit various transmitter functions, during the step-start sequence and when the
transmitter is off.
A “Turn-on Request” from the power control logic starts the
turn-on sequence. Turn-on/turn-off control logic turns the transmitter on in stages or steps, and provides logic outputs to other
parts of the transmitter during the turn-on sequence. If something
goes wrong during the turn-on sequence, turn-on may either be
03/16/2009
aborted immediately or may just time-out without completing
the turn-on sequence.
An “OFF” input, also from the power control logic, immediately
de-energizes high voltage supply contactors and generates other
logic signals to inhibit other transmitter functions. A Type 1 or
Type 2 Fault input logic signal has the same effect as an OFF
input. If an “Off” or Type 1 or Type 2 fault signal occurs during
the step-start (turn-on) sequence, the sequence is immediately
stopped or aborted.
Although the turn-on/turn-off control logic is straightforward
and fairly simple, you will probably have to work through the
following explanation several times to understand the circuit.
Most transmitter turn-on/turn-off circuits require some study to
understand, because often one step must be completed before the
next can be started, and because fault and overload inputs can
modify or stop the turn-on sequence.
P.3.0.1 Basic Turn-On Sequence Requirements
The DX-10 has no filaments to warm up, so a “Turn On Request”
immediately starts the high voltage supply step-start sequence.
Primary power is initially applied to the high voltage power
supply through surge limiting resistors, in the first step of the
step-start sequence. The RF power amplifiers are held off during
this time, so that the PA does not load the power supply as its
filter capacitors charge (the RF Driver section does load the
supply lightly). Also, the first step-start relay is checked; if it has
closed, the turn-on sequence continues.
After a short time delay, rf drive level is checked (for both
overdrive and underdrive; either could damage to PA modules
when they are turned on). If drive is not correct, the transmitter
is turned off immediately. There are two possible causes of low
rf drive. First, an rf drive section fault can result in no drive or
low drive, and second, a high voltage supply fault can result in
low supply voltage to the rf driver, and therefore low rf drive
level.
If rf drive level is correct, and the second step-start relay (K2)
closes to apply primary power directly to the high voltage supply
transformer, power control circuits become completely operational and after an additional short time delay the “PA Off” logic
signal is released so that the transmitter begins operating at the
selected power level (High, Medium or Low power).
P.3.1 Inputs to Turn-On/Turn-Off Control Logic
Logic signals, the circuit which generates them, and their basic
function are:
a. TURN-ON REQUEST, from Power Control Logic:
1. Starts turn-on sequence.
b. “OFF” (Logic HIGH), from Power Control Logic:
1. De-energizes step-start contactor K2, and
2. Generates “PA Off” logic signal, and
3. Sets Power Control latch (U42) to “OFF.”
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-1
c. PA TURN-OFF (Logic LOW), from External Interface:
Generates “PA Off” logic signal, but does not de-energize
high voltage supply contactors.
d. “PA OFF,” from PA Off Switch S5, on Controller board:
Generates “PA Off” logic signal, when switch is in “PA
Off” position. Turns PA off, but does not de-energize high
voltage supply contactors.
e. SUPPLY FAULT - L, from Controller board Supply Fault
circuit:
1. During turn-on sequence: Immediately stops turn-on
sequence.
2. During operation: Immediately de-energizes step-start
contactor K2.
f. TYPE 1 FAULT - H, from Interlock Fault Circuit on
Controller Board and from LED Board:
1. De-energizes step-start contactor K2 (and K1, if during
turn-on sequence), and
2. Generates “PA Off” logic signal, and
3. Sets Power Control latch to “OFF.”
g. TYPE 2 FAULT - H, from LED Board:
1. De-energizes step-start contactor K2 (and K1, if during
turn-on sequence), and
2. Generates “PA Off” logic signal.
h. K1 AUXILIARY CONTACT (“K1 Has Closed” logic
input).
1. Immediately releases “Underdrive Inhibit B”
2. After 0.3 seconds, releases “Underdrive Inhibit A”
3. After 1.1 seconds, generates “K2 drive” signal.
i. K2 AUXILIARY CONTACT (“K2 Has Closed” logic
input).
j. Latches K2.
k. Keeps “Underdrive Inhibit A” released.
l. After 150 milliseconds, releases “PA Off” signal, allowing
PA modules to turn on.
P.3.2 Outputs From Turn-On/Turn-Off Control
Logic
Turn-on/Turn-off logic outputs include:
a. K1 (Step-Start Contactor) Drive: 1.6 second “Turn-On”
pulse generated by K1 Turn-On Monostable U50A energizes K1 coil. The turn-on pulse goes to a contactor drive
circuit on the DC Regulator board (A30), and a triac
contactor drive circuit energizes ac contactor K1’s coil.
b. K2 (Contactor) Drive: Energizes K2 coil, through a triac
contactor drive circuit on the DC Regulator board.
c. Type 1 or Type 2 Fault - H, to Power Control Logic:
Enables “Power Mode” logic as determined by the Control
latch (U42), and enables BCD Power Control output.
d. Inverted K1 Turn-On Pulse, to LED Board: Inhibits “RESET” function during turn-on)
e. PA OFF logic signal, to LED Board: Turns PA modules
OFF.
P-2
f. RELEASE INHIBIT - H, logic output, to Power Control
logic: Inhibits clock, to prevent raise/lower controls from
operating during turn-on
g. OVERDRIVE INHIBIT - H, logic output, to LED Board:
Inhibits Air Flow and Overdrive fault sensing during turnon.
h. UNDERDRIVE INHIBIT - A: Inhibits Underdrive fault
sensing during turn-on.
i. UNDERDRIVE INHIBIT - B: When released, resets underdrive fault sensing “reference voltage” ramp-up.
P.4 Turn-On/Turn-Off Logic Flow
This section describes turn-on/turn-off control logic operation
for a number of inputs, including:
a. Transmitter Turn-On, from an “OFF” condition.
b. Faults during the Turn-On Sequence: K1 or K2 don’t
energize.
c. Turn-on/Turn-off Logic States, When the Transmitter is
ON.
d. Power Level Change, with the transmitter already ON.
e. Transmitter turn-off.
f. “Off” Command, during the turn-on sequence.
g. Faults during the turn-on sequence: Type 1 or Type 2
Fault, or “Off” command.
h. Controller board Supply Fault during the Turn-on sequence.
i. “Brown-Out” or Controller board Supply Fault during
normal operation.
j. Type 1 or Type 2 Fault, when the transmitter is ON.
k. Type 2 Fault: Recycle transmitter off then on.
l. AC Power Recycle (Recycle “ON” after power failure).
P.4.1 Transmitter Turn-On, From “OFF” Condition
When you depress the HIGH, MEDIUM, or LOW pushbutton
switch, you will see the pushbutton switch illuminate then hear
contactor K1 energize. After about 1.1 seconds you will hear
contactor K2 energize, then the power output will come up to the
preset level. After another half-second you will hear contactor
K1 de-energize.
P.4.1.1 Turn-On Sequence:
Refer to Figure P-1, “Turn-On/Turn-Off Control Logic Block
Diagram.” If the transmitter is OFF and there are no fault inputs,
the following turn-on sequence occurs:
a. Command Input. When a HIGH, MEDIUM, or LOW
power command is given (either a LOCAL or a REMOTE
input), a “TURN-ON REQUEST” is generated by the
Power Control logic.
b. Turn-On Request. The Turn-On Request (low-to-high
transition) triggers K1 Turn-On Monostable (one-shot)
U50A, at its B input, starting a 1.6 second “Turn-on” pulse.
If the transmitter is already on, an INHIBIT (logic HIGH)
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
c.
d.
e.
f.
g.
signal at the one-shot’s “A” input prevents the turn-on
pulse from being generated.
Turn-On Pulse. When U50A is triggered, it generates a 1.6
second logic HIGH “Turn-On Pulse” at its Q output, and
a 1.6 second logic LOW inverted turn-on pulse at its Q-not
output. The Turn-on pulse drives step-start contactor K1,
and the end of the inverted pulse generates a “Data Strobe”
signal for the Analog Input board data latches. (Note that
an “Off” or any “Fault” input during the 1.6 second turn-on
pulse CLEARS the one-shot, immediately aborting the
turn-on sequence).
K1 HAS CLOSED. When K1 closes, an auxiliary contact
places a +22 volt signal at the input of a de-bounce and
logic level converter circuit (Q5C and U59C). U59C’s
output is a “K1 Has Closed” signal, which goes HIGH,
and:
1. Releases “Underdrive Inhibit - B” (resets the underdrive comparator reference voltage ramp, on the LED
Board), and
2. Starts a 0.3 second delay timer (U59A and U59F).
K1 HAS CLOSED + 0.3 SECONDS. 0.3 seconds after the
“K1 has closed” input, delay timer U59A-U59F provides
a logic HIGH output, which:
1. Releases “Underdrive Inhibit - A” (enables the underdrive fault output on the LED board). This HIGH goes
to one input of OR gate U58B forcing the gate’s output
HIGH. Gate U58B’s other input keeps the output HIGH
as long as K2 is closed and the transmitter is on.
2. Starts a 0.8 second delay timer (U57A, U57B). The
output of this second timer is a “K1 HAS CLOSED +
1.1 SECONDS” logic HIGH signal.
K1 HAS CLOSED + 1.1 SECONDS. The 0.8 second
delay’s logic high output occurs (0.3 + 0.8) = 1.1 seconds
after the “K1 Has Closed” input. This logic HIGH signal:
1. Generates a “K2 DRIVE” output, if no faults are present. The logic HIGH signal goes through OR gate
U58A, AND gate U52B, and AND gate U52C. OR gate
U58A’s other input latches K2. If no “Inhibit K2 - L”
signal is present at U52B and no “Supply Fault - L”
signal is present at U52C, the K2 Drive signal energizes
step-start contactor K2.
2. Generates a RELEASE INHIBIT - H signal, at U58A
output, which allows clock pulses to go to the power
control logic up-down counter control gates. Until now,
the “RELEASE INHIBIT - H” logic line has been low,
inhibiting clock pulses through the Power Control logic
Clock Inhibit gate U68B).
K2 HAS CLOSED. When K2 closes, an auxiliary contact
places a +22 volt signal at the input of a de-bounce and
logic level converter circuit (Q5D and U59B). The output
from the converter, a “K2 Has Closed” logic HIGH signal:
1. Latches K2, if no faults are present. The “K2 HAS
CLOSED - H” input to OR gate U58A holds the gate’s
output HIGH, AND gate U52B’ output goes HIGH, and
03/16/2009
AND gate U52C’s output goes HIGH. Gate U52C’s
logic HIGH output is the “K2 drive” to the contactor
drive circuit on the DC regulator board. (An “Inhibit
K2 - L” at AND gate U52B or a “Supply Fault - L” at
AND gate U52C inhibit or blocks the K2 Drive signal).
2. Inhibits “K1 Turn-On Monostable” U50A, so that another power mode change (which generates another
“Turn-On Request”) cannot trigger another Turn-On
Pulse.
3. Holds the “Release Inhibit - H” line from OR gate
U58A’s output HIGH; also refer to 6(b), above.
4. Starts a 150 millisecond delay timer, U59E. After 150
milliseconds, the delay timer output goes from HIGH
to LOW, releasing the “PA OFF” and allowing PA
modules to come on.
h. 150 MILLISECOND DELAY TIMER, U59E. 150 milliseconds after the “K2 has closed” signal goes HIGH, this
delay timer’s output goes LOW providing an input to gate
U53B.
i. Negative-Input AND gate U53B. If no faults are present,
this gate’s output goes HIGH 150 milliseconds after K2
closes. Also, refer to the paragraphs describing the “PA
Off and Overdrive Inhibit gate U53B” later in this section.
When gate U53B’s output goes HIGH, it:
1. Releases “Overdrive Inhibit.” The “Overdrive Inhibit L” is released so that Overdrive sensing circuits and Air
Flow Fault circuits on the LED Board (A32) are allowed to operate.
2. Releases the “PA OFF - L” signal, allowing the PA to
turn on (unless an “External PA OFF” or “PA Off”
switch S5 on the Controller board, or PA Off signals
from other parts of the transmitter, still hold the PA off).
j. At this time, about 1.2 seconds has elapsed since the
“Turn-On Request,” and the transmitter is “ON.” The 1.6
second “K1 TURN-ON” pulse will remain HIGH for
about 0.4 more seconds, then it will go LOW, K1 Drive
will be removed, and K1 will de-energize.
P.4.2 Faults During the Turn-On Sequence:
K1 Or K2 Don’t Energize.
If the one of the high voltage supply contactors doesn’t energize
during the turn-on sequence, the turn-on sequence won’t be
completed. The following paragraphs describe turn-on/turn-off
circuit actions if either K1 or K2 doesn’t energize.
P.4.2.1 Contactor K1 Does Not Energize.
If high voltage supply step-start contactor K1 does not energize,
no further turn-on sequence steps occur because K1’s auxiliary
contact must close to continue the turn-on sequence. After 1.6
seconds, the K1 Turn-On Pulse goes LOW, K1 drive is removed,
and the transmitter remains OFF.
P.4.2.2 Contactor K2 Does Not Energize.
When the 1 second turn-on pulse ends, K1 simply de-energizes,
removing all primary power from the high voltage supply. The
transmitter is then OFF, but the High, Medium or Low indicator
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-3
lamp and corresponding remote status output will remain ON
until the transmitter is turned OFF by depressing the “Off”
pushbutton or giving a remote control “Off” command. Some
turn-on functions occur, as follows:
a. High voltage supply primary power is applied by K1,
through the step-start resistors, but the “PA OFF” signal
keeps PA modules OFF. RF driver circuits will come on,
however.
b. “Underdrive Inhibit B” is released when K1 energizes,
then 0.3 seconds later Underdrive Inhibit A is released.
When K1 drops out, these Inhibit functions will return.
c. 1.1 seconds after K1 energizes, the “Release Inhibit H”
signal is generated, but again is removed after K1 drops
out.
d. All other turn-on sequence steps occur after K2 energizes.
When K2 does not energize, no further steps occur.
Type 1 or Type 2 faults, or Controller board supply faults, during
the turn-on sequence are described separately.
P.4.3 Turn-On/Turn-Off Circuit Logic States, When
the Transmitter Is ON
Again, refer to Figure P-1. When the transmitter is ON, K2 is
energized, and the following signals are present in the Turnon/Turn-off Control Logic:
a. “K2 is Closed” logic HIGH signal at U59B output (and
input to following gates).
b. LATCH K2: K2 is Closed - H" at U58A latches K2 “ON.”
Both inputs to Inhibit Gate U52B are HIGH and, U52B
output is HIGH, both inputs to “Supply Fault” Inhibit Gate
U52C are HIGH and U52C output is HIGH, input to K2
drive transistor Q5A is HIGH and Q5A collector is LOW.
c. RELEASE UNDERDRIVE INHIBIT A: K2 is Closed H” at U58B keeps “Underdrive Inhibit A” released.
d. RELEASE PA OFF: “K2 is Closed - H” at the input to
U59E delay circuit keeps “PA Off” released.
e. INHIBIT TURN-ON PULSE: “K2 is Closed - H” is applied to Turn-On Monostable U50A’s input, through buffer U69A, to inhibit K2 and prevent another “Turn-On
Request” from generating a new K1 Drive pulse while the
transmitter is ON.
P.4.4 Power Level Change, with the Transmitter Al-
ready ON: Turn-On/Turn-Off Logic Flow
When you change power level by depressing the HIGH, MEDIUM, or LOW pushbutton switch while the transmitter is ON,
you will only see the new switch illuminate and the transmitter’s
power output will change. No contactors operate.
P.4.4.1 Turn-On/Turn-Off Circuit Action
In the turn-on/turn-off circuit, a new Turn-on Request is received
from the Power Control logic, but Turn-On Monostable U50A
is inhibited. There are no other signal changes in the turnon/turn-off control logic change.
P-4
P.4.5 Transmitter Turn-Off: Turn-On/Turn-Off
Control Logic Sequence
When you depress the “OFF” button, the HIGH, MEDIUM or
LOW button light goes out, you will hear contactor K2 de-energize, and power output drops to zero. A remote “OFF” command
or a Type 1 Fault induced “OFF” command cause the same
circuit action as depressing the OFF button.
When a latched, logic HIGH “OFF” signal is received from the
power control logic, the following sequence takes place:
a. Generates “INHIBIT K2 - L.” The “OFF-H” signal at one
input to NOR gate U53C causes the gate’s output to go
LOW. This is an “Inhibit K2-L” signal. The “Inhibit K2-L”
signal:
b. TURNS OFF HIGH VOLTAGE SUPPLY (“K2 Inhibit”
gate U52B): The logic LOW input at U52B pin 4 inhibits
the K2 Drive signal and K2 de-energizes, removing primary power from the High Voltage supply. K2 is inhibited
as long as the latched “OFF” command is present.
c. INHIBITS TURN-ON PULSE. The “Inhibit K2-L” signal
goes to Power Control logic gates U43A, B and C, to
inhibit turn-on requests; HIGH, MED, and LOW status
indicators; raise/lower functions; and multiplex output.
These functions are inhibited as long as the latched “OFF”
command is present.
d. TURNS PA MODULES OFF (“PA Off” gate U53B,
through inverter U59D). The logic LOW input causes a
“PA OFF - L” output which holds the PA modules OFF.
The PA is held OFF as long as the latched “OFF” command is present.
e. INHIBITS “OVERDRIVE” AND “AIR FLOW” FAULT
SENSING (“PA Off” gate U53B, through inverter U59D).
When the PA is turned off, these Fault and Overload
functions are also inhibited by a logic LOW “inhibit”
signal.
f. When K2 de-energizes, its auxiliary contact opens, and the
“K2 is Closed - H” line goes LOW. This causes the
following circuit actions:
g. Removes “LATCH K2" signal to U58A pin 2. K2 cannot
energize again until another ”Turn-on" request starts the
turn-on sequence again.
h. Holds “PA Off” (through U59E Delay circuit and gates
U53B and U52A). The PA Off signal remains until K2
energizes again.
i. Inhibits Air Flow and Overdrive fault sensing (through
U59E delay circuit and gate U53B). “Overdrive Inhibit H” is present.
j. Inhibits Underdrive fault sensing (on the LED board),
through gate U58B. “Underdrive Inhibit-A” signal is present.
k. Inhibits Power Change. The output of gate U58A goes
LOW, removing the “Release Inhibit-H” signal and inhibiting the clock input to the up/down counters (through gate
U68B in the power control logic).
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
l. Removes the K1 Turn-On one-shot inhibit input (through
buffer U69C to one-shot U50A’s “A” input. (Recall that
as long as the “OFF” command is present, the one-shot’s
CLEAR input is LOW, so the one-shot still cannot operate).
P.4.6 “OFF” Command During the Turn-On Se-
quence
The circuit action is the same as for a Type 1 or Type 2 Fault
during the turn-on sequence. See the next paragraphs.
P.4.7 Faults During the Turn-On Sequence: Type 1
or Type 2 Fault, or OFF Command
Any of these inputs generates an “Inhibit K2 - L” signal at the
output of gate U53C, causing the same circuit action as described
for “Transmitter Turn-Off.” If K2 has not yet energized, a
“CLEAR - L” signal at the output of gate U52D clears the
Turn-On one-shot, stopping the turn-on pulse and de-energizing
K1, so that the turn-on sequence stops. Further action is as
follows:
a. Latched “OFF” command: The transmitter is OFF. A Type
1 fault generates an “OFF” command, or this could occur
if the operator depressed HIGH, MEDIUM or LOW then
immediately depressed the OFF pushbutton.
b. Type 1 Fault: A Type 1 Fault generates an “OFF” command. Refer to (a), above.
c. Type 2 Fault: Type 2 Faults includes rf overdrive, rf
underdrive, and supply current overloads. A type 2 fault
recycles the transmitter after about 2.4 seconds; see the
description of “Type 2 Fault: Recycle Transmitter Off
Then On.”
P.4.8 Controller Board Supply Fault During the
Turn-On Sequence
A Supply Fault during the turn-on sequence clears the Turn-On
one-shot, immediately de-energizing K1, and inhibits (blocks or
removes) the K2 drive signal, through gate U52C, if K2 has
already energized.
P.4.9 “BROWN-OUT” or Controller Board Supply
Fault During Normal Operation
P.4.9.1 Brown-Out
A “Brown-out,” that is, low incoming ac supply voltage on the
ac power phase which supplies the single-phase low voltage
power supply, will reduce the low-voltage supply’s unregulated
outputs. A 15 to 20% decrease in the +8 volt output will cause a
low regulated +5 volts, which generates a “Fault Alert” and
Supply Fault - logic LOW signal. The Supply Fault - L signal’s
action is described in the next paragraph.
A Supply Fault - L input to the power control section goes
directly to one input of K2 Drive Inhibit gate U52C, causing high
voltage contactor K2 to de-energize and turning off the High
Voltage supply. The “Supply Fault Summary” indicator, LED
DS1 on the Controller board, will also illuminate. When line
voltage returns to normal, the transmitter should restart and
return to normal operation.
03/16/2009
P.4.10 Type 1 or Type 2 Fault, When the Transmit-
ter is ON
The turn-on/turn-off control logic action is the same as for an
“OFF” command, already described. Both cause the HIGH,
MEDIUM or LOW power status light to go out or turn off the
remote status indication. Differences between these inputs are:
a. TYPE 1 FAULT: A type 1 fault turns the transmitter OFF
and latches the OFF command, so that the transmitter must
be turned on again by the operator. A type 1 fault also
causes a RED “Fault” status indication on the transmitter’s
status panel and generates a remote “Fault” status output.
b. TYPE 2 FAULT: Type 2 faults include rf overdrive, rf
underdrive, and high voltage supply overloads. When a
type 2 fault first occurs, the transmitter turns off then
recycles ON again. If the same fault is still present when
the transmitter comes on again, the second Type 2 fault
turns the transmitter OFF. For a description of the “Recycle” action, refer to the description of “Type 2 Fault:
Recycle transmitter off then on.”
P.4.11 Type 2 Fault: Recycle Transmitter OFF then
ON
A Type 2 fault turns the transmitter OFF then recycles it back
on. If the same fault is still present when the transmitter comes
back ON, the second type 2 fault becomes a Type 1 Fault which
turns the transmitter OFF. RECYCLE SEQUENCE: A type 2
fault de-energizes the high voltage supply contactors, turning off
the high voltage supply, and the turn-on/turn-off control logic
“Inhibit” outputs all appear. The Power Level Latch in the Power
Control logic is still latched in the HIGH, MEDIUM or LOW
power mode, however.
The LATCHED “HIGH” “MEDIUM,” or “LOW” power level
signal, and power level inhibit gates U43A, U43B, and U43C in
the Power control logic are the key to DX-10 “recycle ON”
functions, as follows:
a. As long as the Inhibit K2 - L signal is present, power level
inhibit gates U43A, U43B, and U43C (in the Power Control Logic) all have LOW outputs.
b. When the Type 2 Fault input to gate U53C in the turnon/turn-off control logic clears (goes LOW again), the
“Inhibit K2 - L” signal also clears (goes HIGH), and the
turn-off/turn-on control logic is ready for the turn-on sequence, if there are no other faults to keep it off.
c. When the Type 2 fault input goes Low, the Inhibit K2
signal goes HIGH, and the latched HIGH, MEDIUM or
LOW signal signal goes HIGH at the output of its inhibit
gate (U43A, B or C). The “Turn-On Request” line then
goes HIGH, and this low-to-high transition triggers “Turnon one-shot” U50A in the turn-on/turn-off control logic.
This starts a normal transmitter turn-on sequence, as already described.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-5
P.4.12 AC Power Recycle (Recycle “ON” After
Power Failure)
If an AC power failure occurs during normal operation, the
transmitter will automatically recycle ON again, to the same
power level and operating condition as before the power failure
(unless the power failure is long enough to discharge the +5B
“memory back-up supply” - at least two hours when back-up
batteries are NOT installed on the Controller board).
The AC Power Recycle function can be divided into two parts,
described in the next two paragraphs. First, the latched power
level generates a turn-on request when an “inhibit” is released.
Second, when power is first applied to the transmitter, a faultgenerated “off” command is generated, but this “off” command
is not latched because the latch “clock” is inhibited.
P.4.12.1 Generate Turn-On Request:
The Latched “HIGH” “MEDIUM,” or “LOW,” the delayed
“controller supply fault” low to high transition on power-up, and
the “clear” input edge trigger of U50, are the key to DX-10
“recycle ON” functions, as follows:
a. When ac power comes back on, various regulated power
supplies on printed circuit boards generate “Supply Fault”
outputs until the supplies are within 10% of their normal
output voltage. As long as any “Supply Fault” signal is
present, a “Fault” signal input is present to the turnon/turn-off control logic.
b. The power level at the time of the power failure is still
latched in power level latch U42. When all supplies are up
to normal voltage and the “Fault” input clears, and the
“inhibit” inputs of the three power level inhibit gates go
high. The output of the gate for the power level latched in
U42 (HIGH, MEDIUM or LOW power level) goes HIGH,
generating a Turn-On Request which establishes the
proper logic for the B input at U50-2. When the “Supply
Fault” delay returns U50-3 to HIGH, the transition begins
the step-start sequence.
c. The “fault” also generates an OFF command, but this is
not clocked into the power level latch because the “clock”
pulse is inhibited, by the delayed “Supply Fault.” The next
paragraph describes this function.
P.4.12.2 Inhibit Fault-Generated “OFF” Command
While power supplies are coming up to normal voltage, “Supply
Fault” logic outputs generate a Type 1 Fault, which generates a
“Fault Induced OFF” command. After about 20 milliseconds, the
command is decoded and goes to an input to the power level
latch, U42, but is not latched because the “Clock” input to the
latch is inhibited for about two seconds after controller supply
regulator outputs reach their normal voltages and the delayed
Supply Fault -L logic signal goes high. Circuits and functions
providing this “inhibit” are as follows:
a. Power Level Latch U42, “clock” input: The latch “stores”
a power level command when a low-to-high transition
occurs at the “clock” input; that power level command
output goes HIGH and the other outputs go LOW. Until
another “clock” transition, the command is latched and its
P-6
b.
c.
d.
e.
f.
latched output remains high no matter what the latch inputs
are. (Refer to the Power Level control logic descriptions
for more information on the latch, and power level change
pulse circuits).
Power Level Change Pulse: This is a logic LOW pulse
about 10 milliseconds wide, and is generated at the output
of gate U49A each time a new power level command is
decoded. The latch’s “clock” input is at the end of this
Power Level Change pulse, and occurs about 30 milliseconds after any power level command is decoded.
INHIBIT latch “clock” input. The “Power Level Change”
pulse is INHIBITED when pins 1 and 2 of gate U49A are
held LOW, by a “Supply Fault -L.” This forces the latch’s
output HIGH, so that the logic LOW pulse cannot occur
and therefore the power level latch is not clocked.
“Supply Fault - L” circuit. When any of the three Controller board regulated supply voltages are more than 10%
low, the regulator generates a “Supply Fault - L” output.
A fast on/delay off circuit (U67A and U67B) holds this
signal LOW for about two seconds after all Controller
board supplies are up to normal voltage. (Operation of this
circuit is described in the description of “Supply Fault
Circuits” later in this section.
Supply Fault-L, Two second “off” delay: Input commands, including the fault-induced “Off” command, cannot be latched during the two-second delay. During this
delay, the outputs of digital Power Data latches U17 and
U18 (on the Analog Input board) are also held at zero by
a “Data Clear-L” which is generated from the “Supply
Fault-L.” Although the high voltage supply should be on
by the end of this two-second delay, power output is still
zero, and a “Data Strobe” must be generated when the Data
Clear-L signal is removed.
“Data Strobe” (on Analog Input Board A35). At the end
of the two-second delay, the Controller board “Supply
Fault - L” goes high, and the “Data Clear” also goes high.
A circuit on the Analog Input board generates a “Data
Strobe” pulse from the low-to-high transition, and the
digital power data from the up-down counter for the power
level being used is clocked into data latches U17 and U18.
The latch’s outputs go to the digitally controlled potentiometer, and transmitter power output comes up, to the
same output as before the ac power failure. (Refer to
section J, Analog Input board, for details).
P.4.12.3 Summary:
When ac power fails while the transmitter is operating, the
current power level, and digital power output data, are stored in
the power level latch (U42) and in the up-down counters, which
operate from a memory back-up supply (+5B supply). Within a
few tenths of a second after power returns, a “Turn-on Command” is generated by the local (Controller board) supply regulator fault logic to start the step-start and turn-on sequence. This
request is generated after regulators on various boards are up to
normal voltage and all “Supply Fault” (undervoltage) logic
signals are cleared.
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
The “Supply Fault” signals also generate a Type 1 Fault induced
“OFF” command, but a two-second delay in the Controller
board’s supply fault circuit inhibits this command so it is not
latched. The Controller board’s Supply Fault - L signal also
causes a “Data Clear -L” which clears the data latches on the
Analog Input board, A35, and when the Data Clear goes HIGH
after the two-second delay, its low-to-high transition generates
a “Data Strobe” pulse to latch digital power data (on the Analog
Input board), send it to the digitally controlled potentiometer,
and allow the transmitter to come up to power.
P.5 Turn-On/Turn-Off Control Logic:
Circuit Descriptions
The following paragraphs describe operation of one-shot, input,
and delay timer circuits in the Turn-On/Turn-Off Control Logic.
P.5.1 “K1 Turn-On One-Shot” (Monostable U50A)
U50A is one-half of a 74HC123 dual monostable multivibrator,
or “one-shot.” In its normal state, the “Q” output (pin 13) is LOW
and the “Q-not” (also called Q-Bar) output (pin 4) is HIGH.
When the one-shot is triggered, a 1.6 second pulse is generated
at its outputs; the pulse is logic HIGH at the “Q” output and logic
LOW at the “Q-not” (also called “Q-bar”) output. The pulse
width is determined by an R-C network at pin 15, the “RC” input.
When the one-shot is INHIBITED, it cannot be triggered, but if
an INHIBIT input occurs during a one-shot pulse, that 1.6 second
pulse will be completed. When the one-shot is CLEARED, the
output pulse will be stopped immediately; the “Q” output goes
LOW and the “Q-not” output goes HIGH.
P.5.1.1 Trigger
In this circuit, the one-shot is TRIGGERED by one of two
methods, if no faults or inhibit signals are present:
a. A low to high transition at the “B” input, assuming “A”
input is low and the clear input is high. This Trigger
transition is the rising edge of the “TURN-ON REQUEST
-H” logic signal from the power control section.
b. A low to high transition at the “clear” input, assuming “A”
input is low and “B” input is high. This trigger transition
is the rising edge of the delayed supply fault from the local
regulators.
P.5.1.2 Clear
A FAULT or an “OFF” command will CLEAR the one-shot
during the step-start cycle, and will prevent it from triggering
again. When the “CLR” input (pin 3) goes LOW, the “Q” output
goes LOW and the “Q-not” output goes HIGH. The 1.6-second
“Turn-on” pulse is stopped immediately, aborting the turn-on
sequence, and K1 de-energizes. Also, when a fault or “Off”
command holds the CLEAR input LOW, the one-shot cannot
trigger again. (A fault or “Off” command also de-energizes K2).
The following conditions cause a CLEAR - L input and clear
U50A:
b. “INHIBIT K2 - L,” to U52D input.
c. The “INHIBIT K2 - L” signal comes from U53C’s output
and is generated by any of the following three conditions:
1. TYPE 1 FAULT - H, to U53C input
2. TYPE 2 FAULT - H, to U53C input
3. “OFF - H,” to U53C input (the power control latch,
U42, is latched in the “OFF” state).
P.5.1.3 Inhibit
The one-shot is INHIBITED, that is, it cannot be triggered again,
if its “B” input is LOW, its “A” input is HIGH, or its “CLEAR”
input is LOW. The following conditions INHIBIT U50A in this
circuit:
a. “A” input HIGH: The “A” input goes high when K2 is
latched. This prevents a power mode change from generating a new turn-on pulse while the transmitter is operating
normally.
b. “B” input LOW: When the transmitter is “OFF,” or when
an “INHIBIT K2 - L” signal to gates U43A, U43B and
U43C in the power control logic, the “B” input is LOW.
c. “CLEAR” input LOW: Refer to the paragraph above for
Fault conditions which cause a “Clear -L” input.
P.5.2 One-Shot Trigger and Operation During
Transmitter Turn-On
a. When a HIGH, MEDIUM or LOW command is latched
into power control mode latch U42, the latch’s “OFF”
output goes from HIGH to LOW. If there are no faults
present, the “INHIBIT K2" signal at gate U53C’s output
is HIGH, and the ”CLEAR" signal at gate U52D’s output
and at one-shot U50A’s input is HIGH, so that the one-shot
can trigger.
b. At the same time, a HIGH, MEDIUM or LOW command
is latched into power control mode latch U42, and the
corresponding output goes from logic LOW to logic
HIGH. Also, the “INHIBIT K2" signal at power control
logic AND gates U43A, U43B, and U43C goes from LOW
to HIGH, so that one of the gate outputs goes HIGH, and
one input to Turn-On Request ”OR" gate U53A goes
HIGH. This generates a “Turn-On Request” logic HIGH
signal.
c. If there are no faults, “Xmtr Turn-On” monostable U50A
triggers, generating the 1.6 second turn-on pulse.
d. When K2 closes, about 1.1 seconds after the beginning of
the “Xmtr Turn-On” pulse, its auxiliary contact closure
generates a “K2 Has Closed/Latch K2" signal, which
causes one-shot U50A’s ”A" input to go HIGH. The logic
“HIGH” at input “A” inhibits the one-shot, so that it cannot
be triggered again.
P.5.2.1 Logic Levels at U50A Inputs and Outputs
When the transmitter is OFF, U50A’s “A” input (pin 1), “B”
input (pin 2) and “CLR” input (pin 3) are all LOW. When the
transmitter is ON, these three inputs are all HIGH.
a. “SUPPLY FAULT - L,” to U52D input.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-7
P.5.3 Contact De-Bounce and Logic Level Con-
verter Circuits (Q5C-U59C, Q5D-U59B).
These circuits are both the same. The following description
describes the circuit for the “K1 Aux Contact” input.
When the contactor’s auxiliary contact closes, it applies +22
volts to the input, which is both a voltage divider and an R-C
filter which effectively filters out “contact bounce.” The filter’s
time constant also provides a small time delay (several milliseconds). Diode CR1 protects the transistor’s input against any
reverse voltage. Resistor R39 limits base current to transistor
Q5C.
Transistor Q5C acts as a logic level converter. When K1’s
auxiliary contact is open, Q5C is “off” and its collector rises to
about +5 volts (logic HIGH). When K1’s auxiliary contact is
closed, Q5C conducts and its collector goes to almost zero volts
(logic LOW). Because Q5C’s input is from a charging capacitor,
the waveform at its collector has a “long” rise and fall time, and
Schmitt trigger U59C provides an output with a short rise and
fall time.
Inverting Schmitt trigger U59C’s output is logic LOW when the
contactor’s auxiliary contact is open, and logic HIGH when the
contactor is closed. This output is the “Underdrive Inhibit B”
signal which resets the “Underdrive Fault” detector’s ramp (refer
to Section Q, LED Board, for a description of Underdrive Fault
circuits). U59C’s output also drives the 0.3 second delay circuit.
P.5.4 Delay Circuits: Description
P.5.4.1 0.3 Second Delay Timer: Delay on/Fast Off (U59A,
U59F, R34, C103, R115, CR15)
When K1’s auxiliary contact closes, the delay circuit input from
U59C pin 6 goes HIGH, and capacitor C103 begins charging
through R34. Diode CR5 is reverse biased at this time. After
about 300 milliseconds, the voltage across C103 goes above the
trigger threshold of inverting Schmitt trigger U59A, and U59A’s
output goes LOW. U59F inverts this signal, so that about 0.3
seconds after K1 closes the output of U59F goes HIGH.
About 0.3 seconds after K1 closes, U59F’s output goes logic
HIGH, releasing Underdrive Inhibit A through OR gate U58B,
and drives the second, 0.8 second timer. It is at this time that RF
Drive level begins to be measured, and if it does not come up in
a predetermined manner, a Type 2 Fault will be signaled.
When K1 opens again, U59C’s output goes LOW and capacitor
C103 discharges through diode CR15 and resistor R115; the time
constant of this circuit is about 1 millisecond, “resetting” the
delay timer in a short time.
P.5.4.2 0.8 Second Delay Timer (R33, C104, U57A, U57B)
Operation of this timer is like the “Delay On” of the 0.3 second
delay timer. When the 0.3 second delay circuit’s output (at
U59F’s output) goes high, capacitor C104 begins charging
through R33. After about 0.8 seconds, inverting Schmitt trigger
U57A triggers, and its output goes LOW. U57B inverts this
output again, so that the delay timer’s output at U57B’s output
(pin 4) goes HIGH.
P-8
The 0.3 second and 0.8 second delays add, so that U57B generates a logic HIGH signal 1.1 seconds after K1 closes. This logic
HIGH signal is an input to OR gate U58A, so that U58A’s output
also goes HIGH generating a “K1 has closed + 1.1 second delay
- H.” The “K1 has closed + 1.1 second delay” signal generates a
K2 drive signal and also releases a clock “inhibit” to allow
raise/lower functions to operate.
P.5.4.3 50 Millisecond Delay (R32, C105, U59E)
This delay circuit operation is the same as operation of the 0.8
second delay, except for the shorter R-C timer constant. This
delay starts when contactor K2 energizes, completing the stepstart sequence and applying full high voltage. At the end of this
delay, the “PA TURN-OFF” signal from gate U52A pin 3 to the
LED board is released, allowing the PA modules to turn on.
P.5.4.4 “PA Off” and “Overdrive Inhibit” Gate U53B
Gate U53B’s output is HIGH only if all three inputs are LOW.
If any one or more inputs goes HIGH, the output goes LOW.
(Note that U53B can also be described as a NOR gate: if one or
more inputs are HIGH, its NOR - that is, its inverted OR - output
goes LOW). The gate’s inputs are:
a. One input (pin 3) is grounded, holding it LOW all the time.
b. When the transmitter is OFF, the “K2 is closed + 150
millisecond delay” input (U53B pin 4) is HIGH, forcing
the output LOW and its output provides “PA Off” and
“Overdrive Inhibit” outputs, holding the PA off and inhibiting Overdrive Sensing and Air Flow fault circuits.
c. When an OFF command, Type 1 Fault or Type 2 Fault
generates an “Inhibit K2" signal, U53B pin 5 goes HIGH,
forcing the output LOW thus providing an early PA Off
and Overdrive Inhibit.
P.5.5 “PA Turn-Off” (U52A, U53B, and S5)
A PA Turn-off circuit on the Controller board generates a logic
LOW output, which is one input that turns the PA modules off
by clearing all latches on the Modulation Encoder board. This
PA turn-off signal goes through gates on the LED board and then
through gates on the Modulation Encoder board.
The PA Turn-off circuit is shown in the block diagram as part of
the transmitter turn-on/turn-off logic, and generates a logic LOW
“PA Off” signal at the output of gate U52A. The “PA Off” signal
from the Controller board is one input to “OR” gate A32U66 on
the LED board; the output of that gate goes to the Analog Input
board, and to the Modulation Encoder board where it is one input
to a PA Turn-Off circuit that clears all data from the digital power
data latches. Section Q, LED Board, and section L, Modulation
Encoder, include descriptions of PA turn-off circuits on those
boards.
Refer to either the Controller schematic diagram (bottom of sheet
1) or to the block diagram for the following discussion.
P.5.5.1 Gate U52A
If either input to gate U52A is logic LOW, the gate’s output will
be a “PA OFF - L” signal. If BOTH inputs to gate U52A are logic
HIGH, the gate’s output will be HIGH, and there is NO “PA OFF
-L” signal from the Controller. Inputs to Gate U52A are:
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
a. At pin 1: EXTERNAL PA TURN-OFF (active LOW),
from the External Interface, and “PA OFF (active LOW)
from PA OFF switch S5 on the Controller board when the
switch is closed (in the PA OFF position).
b. At pin 2: PA OFF (Active LOW) signal from gate U53B.
P.5.5.2 “PA Off” Gate, U53B
If any one or more inputs to U53B are HIGH, the gate’s output
will be LOW, and a “PA OFF - L” signal will always appear at
the output of U52A.
If all three inputs to U53B are LOW, the output of gate U53B
will be HIGH and gate U53B does not generate a “PA OFF”
signal.
Gate U53B’s inputs are:
a. Pin 3: GROUNDED; always “LOW” (can never generate
a “PA OFF”).
b. Pin 4: “K2 HAS CLOSED + 150 Milliseconds.” This input
holds the PA “OFF” for an additional 150 milliseconds
after K2 energizes (this delay allows time to ensure that no
supply overloads are present).
c. Pin 5: “INHIBIT K2 - H” (This is an inverted “Inhibit K2
- L” signal). The “Inhibit K2" signal is generated when an
”OFF" command is latched or when a Type 1 or Type 2
fault occurs. When an “Inhibit K2" signal is present, a PA
OFF - L output will be generated.
P.6 Power Control Logic: Principles of
Operation
The power control logic circuits accept Command Inputs for
power control and generate a 3-digit BCD (Binary Coded Decimal) power control output which goes to the digitally controlled
potentiometer circuit on the Analog Input Board (A35).
Command inputs are OFF, LOWER, RAISE, HIGH, MEDIUM
and LOW. Command inputs can be LOCAL, REMOTE, or
FAULT-INDUCED. The transmitter’s front panel pushbutton
controls are LOCAL command inputs. Inputs from remote control equipment or extended control panels to the External Interface terminal board (TB1) are REMOTE inputs. The
transmitter’s fault and overload sections can generated Type 1
fault induced OFF commands, VSWR induced LOWER commands, or Crowbar Fault induced LOW Power commands. (This
circuit is presently disabled via a grounded input to U44-5 on the
LED board).
Figure P-2, Power Control Logic Simplified Block Diagram,
shows basic functions of the power control section. Input circuits
accept the command inputs and provide switch de-bounce and
priority select functions. The latest OFF, HIGH, MEDIUM or
LOW command is stored in a “Power Level Latch,” which
operates from the +5B back-up supply, so that after a power
failure the transmitter will come back on in the same power
mode.
The Power Mode Latch “Off” output goes to turn-on/turn-off
control circuits. The High, Medium, and Low outputs are
“OR’ed” to generate a “turn-on request” to the turn-on/turn-off
control logic.
Up-down counter control logic consists of gates which send the
clock pulses to the an up-down counter input for the “latched”
Power Level when a “Raise” or “Lower” command is present.
Up-down counters set and “remember” the transmitter power
output for each power level. There is a set of up-down counters
for each power level (HIGH, MEDIUM and LOW), and when a
power level is selected its up-down counter’s BCD Power Data
output is selected by the Multiplex and goes to the Analog Input
board. The output of each set of counters is a 12-bit, parallel
output, BCD (Binary Coded Decimal) power output data signal.
When either the “Raise” or “Lower” control is operated while
the transmitter is in the HIGH, MEDIUM or LOW power mode,
clock pulses go to the Count Up or Count Down input of the
counters for that mode to change the BCD Power Data. The
counters’ supply is the +5B back-up supply, so that the counter
output does not change unless a “Count Up” or “Count Down”
input is present.
An output Multiplex circuit selects the 12-bit BCD data from one
set of up/down counters, and sends it to the Analog Input Board,
A35. Three Multiplex “Address” inputs (HIGH, MEDIUM or
LOW power level or mode) determine which set of data becomes
the multiplex output; if all three address lines are logic LOW,
Figure P-2
Power Control logic simplified block diagram.
03/16/2009
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-9
the multiplex output is zero (0000 0000 0000). On the Analog
Input Board, the data is stored in latches, then goes to the digitally
controlled potentiometer input (refer to section J, Analog Input
Board, for further information).
P.6.1 “Command” Inputs
There are six different commands to the power control logic
circuits, including: OFF, LOWER, RAISE, HIGH, MEDIUM,
and LOW. For each command, there are two inputs, a manual
input from a transmitter front panel pushbutton switch and an
extended control input (remote control input) through the External Interface A28. Three additional inputs come from transmitter
fault and overload circuits:
a. VSWR-induced “LOWER” command: When a number of
VSWR faults occur within a short time, the transmitter
continues to operate, but its output power is lowered until
reflected power is reduced to a safe level.
b. Fault-induced OFF command: Some faults turn the transmitter OFF, in the same way that depressing the transmitter’s “OFF” pushbutton does. These commands set the
Power Mode Latch to “OFF” and de-energize the high
voltage supply primary power contactors.
c. “Combiner crowbar fault” induced LOW POWER command: (NOT USED IN THE DX-10).
Don’t confuse the “Off” command with the “PA Off” or “PA
Turn-Off” input, which turns off all PA modules through the
transmitter’s modulator section, but does not turn off the high
voltage supply or change the Power Mode Latch. When a “PA
Off” input is released, the transmitter immediately comes back
on at its preset power level.
P.6.2 Other Logic Inputs
Additional inputs to the power control logic include:
a.
b.
c.
d.
Supply Fault (logic Low) signal.
+5B (Memory Back-up supply) fault logic signals.
“Type 1 Fault” (logic Low) signal.
“Release Inhibit” signal, from the turn-on/turn-off logic
(at the end of the step-start sequence).
A “Supply Fault” logic signal from any of the three regulated
supplies on the Controller board immediately inhibits (blocks)
any further command inputs from operating, but does not clear
the power mode latch or up/down counter. The “Supply Fault”
also generates a “Data Clear” which clears power control data
latches on the Analog Input Board, causing output power to go
to zero. (The “Supply Fault” also goes to the turn-on/turn-off
logic to turn off the high voltage supply).
“+5B Reset” logic signals clear the “Power Mode” latch and
clear the BCD up/down counters, setting power level for all three
modes to zero. The +5B Reset signals are generated when the
+5B (memory backup supply) voltage decreases, clearing all
backed-up memory before the supply voltage is too low for
reliable operation.
A “Type 1 Fault” logic signal generates an “OFF” command,
and prevents any further command from turning the transmitter
P-10
back on. It inhibits (blocks) inputs to turn-on request logic and
multiplex address lines, setting the BCD power control data
outputs to zero.
“Release Inhibit” signal: During the transmitter step-start cycle,
the clock input to the BCD up/down counters is inhibited,
preventing any change in power data. The “Release Inhibit”
signal from the turn-on/turn-off control logic removes this clock
inhibit, allowing the raise/lower controls to operate.
P.6.3 Power Control Section: Logic Outputs
Logic output signals include:
a. A “Turn-On Request” signal to the turn-on/turn-off control logic starts the transmitter turn-on sequence.
b. An “Off” signal, to the turn-on/turn-off control logic, turns
off the high voltage power supply by de-energizing stepstart relay K2. If the “Off” signal occurs during the stepstart cycle, it also clears the Turn-on monostable, de-energizing K1 as well.
c. A “Data Strobe” signal clocks the power control data
latches on the Analog Input board whenever any change
in the BCD power control data occurs.
P.6.4 Logic Flow in the Power Contol Section
Normal logic flow will be described. Refer to Figure P-3, Power
Control Section Block Diagram. “Fault” and “Reset” signals will
stop this logic flow, but are described later in this section.
Power control section logic flow, when a local, remote, or
fault-induced command input occurs, is as follows:
a. COMMAND (“CONTROL”) Input Occurs.
b. DECODE/PRIORITY SELECT. About 20 milliseconds
after a command input occurs, a single “priority selected”
output appears at the decoder output (Unless the command
is given within 2.4 seconds after any OFF command). A
decoder output is present only while a control input is
present.
c. Decoder output: OFF, HIGH, MEDIUM, LOW commands:
1. To Power Level Change circuit: see Step 3, and
2. To Power Level Latch: see Step 4.
d. Decoder output: RAISE, LOWER commands (active only
if the transmitter is already ON, in the HIGH, MEDIUM,
or LOW power level mode):
1. To Up/Down Counter control gates: see Step 6, and
2. To Status Indicate Circuits: to illuminate front-panel
pushbutton and provide remote status output.
e. “Power Level Change” Pulse: A HIGH, MEDIUM, LOW
or OFF command generates a Power Level Change pulse
about 20-30 milliseconds after it appears at the Decoder
output. A delayed, 10-millisecond power level change
pulse occurs only when a power level command is given.
When a Supply Fault exists, the Power Level Change pulse
is blocked. When a pulse occurs, it goes to circuits which:
1. Clock the Power Level Latch (step 4), and
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
f.
g.
h.
i.
j.
k.
2. Generate a Data Strobe pulse (step 8).
Power Level Latch: A HIGH, MEDIUM, LOW or OFF
command is Latched (“stored”) in U40 when the latch is
clocked by the Power Level Change pulse (from step 3).
One latch output is ALWAYS present (logic HIGH) unless
the backup supply has failed. Latch outputs are:
“OFF” Command latched: an “OFF” command goes to:
1. Turn-on/Turn-off control logic, to turn the transmitter
off, and
2. “Decode inhibit” one-shot trigger input, to prevent
turning the transmitter on again for 2.4 seconds.
“HIGH,” “MEDIUM” or “LOW” command latched: Unless INHIBITED (blocked) by a Type 1 or Type 2 fault,
these three commands go to:
1. Status Indicate Circuits, to illuminate front-panel pushbutton and provide remote status output, and
2. Multiplex Address inputs (See Step 5), and
3. Turn-On Request Gate, to generate Turn-On request for
turn-on/turn-off control logic (starts turn on sequence
unless the transmitter is already on), and
4. Up-down counter control gates, to route clock pulses to
the correct counter when a Raise or Lower command is
given (also see step 6).
Multiplex Address: Latched HIGH, MEDIUM and LOW
commands immediately select the output of one of the
up/down counters, which “stores” 12-bit BCD power level
“word,” and sends that data to the Analog Input board
(address data from latch, step 4b, above).
Up/down counter input gates. These gates route a clock
pulse to only one counter input if a HIGH, MEDIUM or
LOW input and a RAISE or LOWER input to the gates are
present, and if the clock pulse is not inhibited during the
turn-on cycle. If the transmitter is OFF or if a Raise or
Lower command is not present, there is no clock pulse to
any counter. Clock pulse outputs are:
1. Six “clock pulse” output lines, one to each up/down
counter inputs (clock pulses on no more than one line
at a time; may be no clock pulses), and
2. When a clock pulse is present on any output line, a clock
pulse also goes to the Data Strobe (step 8).
Up-down counters: There are three up-down counters, one
each for HIGH, MEDIUM and LOW power levels. Outputs and inputs are:
1. OUTPUTS: Each up-down counter always has a 12-bit
BCD output (the last power output data set in that
counter), unless the backup supply fails. If the transmitter is in the HIGH, MEDIUM, or LOW power level
mode, that counter’s output is selected by the Multiplex
and goes to input latches on the Analog Input board.
2. INPUTS: Each counter can count UP or DOWN when
clock pulses are sent to its count-up or count-down
input, and transmitter power changes as the counter
“counts.” Clock inputs are determined by the input
control gates (step 6, above).
03/16/2009
l. Data Strobe: Inputs to Data Strobe gate U45A are delayed
100 microseconds, then strobe the digital power data
latches on the Analog Input board when:
1. The transmitter is turned on (inverted K1 Start Pulse
generates Data Strobe), or
2. Any Power Level Change occurs (Power Level Change
pulse, see step 3 above), or
3. Any up/down counter has a count up or count down
clock pulse input (see step 7, above).
P.7 Power Control Logic: Circuit De-
scriptions
Figure P-3 is a Detailed Block Diagram of the power control
section, which will be useful for following signal flow between
functional circuits. Also, refer to sheets 1 and 2 of the Schematic
Diagram.
P.7.1 Command Input Circuits: Description
Command input circuits (also referred to as “Control Input”) are
shown in the upper left part of Sheet 1 of the Controller Schematic Diagram. Also, Figure P-4 is a simplified diagram of a
Command Input circuit. Any command input provides a logic
LOW input to the Switch Debounce integrated circuit, U3. Three
of the command inputs are inhibited when an RF Combiner
Crowbar Fault is present, by a section of quad 2-input OR gate
U46 (the Combiner Crowbar Fault is not used on the DX-10).
There are either two or three command inputs for each input to
the Switch Debounce IC. These are LOCAL and REMOTE
inputs for all commands, and Fault-Induced command inputs for
OFF, LOWER, and LOW commands. Each input, which is logic
HIGH when active, goes to a transistor base.
For each command, the two or three input transistors’ collectors
are tied together, forming a NOR gate. If one or more inputs for
a command are active HIGH, the output at the transistor collectors is LOW. When all inputs are LOW, the transistors are OFF
and the collector line rises to nearly +5 volts (logic HIGH)
through a pull-up resistor to +5 volts. If one or more inputs are
HIGH, that transistor (or transistors) turn ON, and the collector
line is pulled to ground (logic LOW).
For each command, the input transistor “NOR” gate’s output
goes to a switch-debounce input, either directly (Figure P-4a) or
through an “inhibit” gate (Figure P-4b). When a control input
(command) is present, that switch de-bounce input is LOW.
P.7.1.1 “Local Control” Inputs
Each Local Control input is from a transmitter front panel
pushbutton switch mounted on the Switch Board/Meter Panel
assembly, A31. On the Controller board, the six local control
inputs go to four sections of transistor array Q2 (Q2A through
Q2B) and to two sections of Q3 (Q3A and Q3B).
At each local control input, there is a pull-down resistor to
ground and a series current-limiting resistor to the transistor’s
base. When the front-panel pushbutton switch is open the pull-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-11
Figure P-4
Controller board command input circuit.
down resistor holds the transistor’s base at ground and the
transistor is OFF. When the pushbutton switch is depressed, the
transistor’s input circuit goes to +15 volts through the pushbutton
switch, the transistor turns ON, and the transistor collector goes
LOW.
P.7.1.2 “Extended Control” Inputs
Each extended control input comes from an opto-isolator on the
External Interface Board, A28. When sufficient current flows
through the opto-isolator’s input LED, its transistor turns ON,
again pulling the collector line to ground (unless the “Local-Remote” switch is in the “Local” position). The opto-isolator’s
internal transistor is paralleled with the corresponding Local
Control input transistor, so that when it turns on it also pulls to
ground the input to switch de-bounce IC or to an OR gate (U46A,
U46B or U46C) LOW.
The opto-isolator’s transistor emitters are connected together, at
the controller input, and go to a “Local-Remote” switch, which
is mounted on the LED board and is a front-panel control (a
toggle switch, on the Status Panel). When the switch is in the
“Local” position, the emitters are returned to +5 volts, so that the
“Remote” inputs at External Interface terminal boards TB1 and
TB2 cannot operate. When the switch is in the “Remote” position, the opto-isolator emitters are all grounded and the “Remote” inputs can operate (all “Local” inputs still operate as well;
they are not affected by the “Local-Remote” switch position).
P.7.1.3 “Fault-Induced” Commands, Command Inputs
From Fault and Overload Circuits
Three transmitter “Fault” conditions provide power level “Command” inputs. Each “Fault” condition turns on a transistor which
is paralleled with the Local Control input and Extended Control
input transistors, so that a “Fault” induced command will also
pull the corresponding switch de-bounce IC input LOW. Faultinduced commands include:
P-12
a. VSWR INDUCED LOWER COMMAND. A Logic
HIGH input from the VSWR Fault circuits on LED Board
A32 turns on Q4C.
b. “TYPE 1 FAULT” INDUCED “OFF” COMMAND.
Either a Type 1 Fault, logic HIGH signal from the LED
board or an Interlock Fault from the Controller board
causes the output of OR gate U56C to go HIGH, turning
on transistor Q4A.
P.7.2 Inhibit Gates (U46A, U46B, U46C)
In the DX-10, these three gates act as buffers. The output of each
gate is normally HIGH and goes LOW when its control input is
active (Control inputs are U46C-9, U46B-5, and U46A-2). The
“Inhibit” inputs (U46C-10, U46B-4, and U46A-1) remain in a
logic LOW state. Recall that an OR gate output is LOW if both
inputs are LOW, and is HIGH if one or both inputs are HIGH.
A logic HIGH at the gate’s Inhibit Inputs (pins 10, 4, and 1)
would hold the OR gate outputs HIGH and block “High,”
“Medium,” or “Raise” control inputs by preventing the gate
outputs and Switch Debounce IC inputs from going LOW. The
“Combiner Crowbar Fault” input is not used in the DX-10, so
U51C’s input is always HIGH and its output is LOW. Transistor
Q4 also remains OFF.
P.7.3 Switch De-Bounce (U37)
The Switch De-Bounce uses an MC14490 integrated circuit
“Hex Contact Bounce Eliminator,” which includes six independent “contact bounce eliminator” sections and an internal
“clock” oscillator. Each contact bounce eliminator’s input is
pulled “HIGH” by an internal pull-up resistor to the +5 volt
supply, unless a command pulls the input LOW to activate the
input. (More usual contact bounce eliminator circuits require a
switch with two sections, one normally open and one normally
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
closed; the “reset” switch circuit on the LED board is an example).
P.7.3.1 Why is a De-bounce Circuit Used?
When a switch is operated (either turned on or off), the contacts
typically “bounce” rapidly between open and closed several
times. With high-speed logic, the logic can interpret this as
several switch operations. A de-bounce circuit’s output is a logic
signal with a single transition.
P.7.3.2 Internal “Clock” Oscillator
The oscillator frequency is determined by an external capacitance connected between pins 7 and 9. The 0.01 mf capacitance
used here gives a period of about 5 milliseconds. The clock
oscillator’s output is also available at pin 9, and is buffered by
U69A for use in other sections of the power control circuits.
P.7.3.3 “Contact Bounce Eliminator” Operation
Each section of the MC14490 requires a “clean” input (contact
“bounce” has stopped) for 3-1/2 to 4-1/2 clock cycles before the
output can change state. Any “Command” input must therefore
be held LOW for at least 20 milliseconds before the contact
bounce eliminator provides a command (logic LOW) to the rest
of the circuit. Also, when the command goes HIGH again, there
is a delay of about 20 milliseconds (3-1/2 to 4-1/2 clock cycles)
before the contact bounce eliminator goes high.
NOTE
IMPORTANT: ANY COMMAND INPUT MUST BE HELD FOR
A MINIMUM OF 20 MILLISECONDS TO OPERATE THE
COMMAND. COMMAND INPUT PULSES LESS THAN 20 MILLISECONDS LONG WILL PROBABLY NOT BE RECOGNIZED
BY THE TRANSMITTER.
P.7.4 Priority Encode/Decode
The Priority Encode/Decode circuit ensures that if two command
inputs occur at the same time, only the one with the higher
priority will be executed. An “OFF” command has the highest
priority, and a “LOW” power mode command has the lowest.
Command priorities, from highest to lowest, are as follows:
1. OFF ...... Highest priority
2. LOWER
3. RAISE
4. HIGH
5. MEDIUM
6. LOW ..... Lowest priority
Example: A local “OFF” command will override any remote
command, and a fault-induced “OFF” command during turn-on
will override any other command.
P.7.5 Priority Encoder and Decoder Circuit Descrip-
tion
The priority encode/decode circuit uses a 74LS148 8-line to
3-line Priority Encoder (U38), a 74HC138 3-to-8 line decoder
(U40), and three inverters (U39, sections D, E and F). Figure P-5,
“Priority Encode/Decode Function Table,” shows logic signals
for the Encoder and Decoder circuit in the DX-10.
There are some encoder/decoder control functions which are not
used in this circuit, and are not shown in the figure. The EN03/16/2009
CODER (U38) is enabled at all times, and the DECODER (U40)
circuit is configured so that a single logic input at pin 4 enables
or disables the decoder. Functions not used, and held HIGH
(resistor to +5 volts) or LOW (grounded) include:
a. PRIORITY ENCODER (U38):
1. “ENABLE” input E1 (U38 pin 3) is held LOW to
ENABLE the encoder at all times.
2. INPUT LINES: Only six of the eight encoder inputs are
used. Inputs D0 and D1 (pins 10 and 11) are held HIGH.
3. The PRIORITY ENCODER also has “GS” and “EO”
outputs, at pins 14 and 15, which are NOT used in this
circuit and are therefore not shown in these function
tables or on the schematic diagram.
b. PRIORITY DECODER (U40):
1. The PRIORITY DECODE IC has three “Enable” inputs, at U40, pins 4, 5 and 8. In this circuit, pins 5 and
8 are grounded, or held LOW. Pin 4 then functions as
a “DECODE ENABLE” input, as follows:
c. Pin 4 LOW: Decoder enabled.
d. Pin 4 HIGH: Decoder disabled (all outputs remain HIGH).
1. Only six Decoder outputs are used (Y2 through Y7).
The Y0 and Y1 outputs are not used, and no connection
is made to them. These pins will always remain HIGH.
P.7.6 Encoder and Decoder Operation
You may find it useful to refer to Figure P-5, Priority Encode/Decode Function, when reading the next paragraphs.
P.7.6.1 Encoder
For each encoder input (D0 through D7), there is a corresponding
binary “code” on the three output lines. If more than one input
is active (logic LOW), the highest priority input which is active
will determine the output “code.” When a higher priority input
occurs, the output lines will immediately change to the new
binary code required by the new input. The encoder, therefore,
selects the highest priority input and provides its binary code on
the three output lines.
P.7.6.2 Inverters
The encoder’s output signals are inverted, by U39D, U39E, and
U39F, then go to the decoder’s “select” inputs (A, B, and C).
P.7.6.3 Decoder
Unless the DECODER is inhibited, it will convert the encoded
3-bit logic signal at its A, B, and C inputs back to a logic LOW
signal on only one of its outputs. Recall that if more than one
command occurs at the same time, only the highest priority
command will appear at the decoder’s output. If NO commands
are active, all decoder outputs will be HIGH. This will be the
case most of the time, as remote control equipment should
provide only a pulse except for RAISE and LOWER commands.
P.7.6.4 Decoder: Inhibit Decode
Decoder operation is inhibited for about 2.4 seconds after any
OFF command is given. This prevents any new command from
operating, and prevents rapid on-off cycling of the transmitter’s
high voltage supply which could result in damage if the supply
is turned “on” while its crowbar SCR, CR16, is still on. Recall
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-13
Figure P-5
Priority Encode/Decode circuit function tables.
P-14
888-2247-006
WARNING: Disconnect primary power prior to servicing.
03/16/2009
that Decoder IC U40 operates when pin 4 is LOW and is
inhibited when pin 4 is HIGH.
signals that strobes the latches on the Analog Input board, storing
the new BCD power output data.
P.7.6.5 Inhibit Decode One-Shot, U50B
Power level (or “power mode”) commands are OFF, HIGH,
MEDIUM, and LOW. Whenever a new power level is latched
into the Power Level latch (U42), a 20 millisecond delay timer
starts (R128-C128-U51B) and at the end of that time-out a 10
millisecond Power Level Change pulse (Logic LOW) is generated. A transistor circuit (Q4D) starts a new Power Level Change
pulse immediately if an OFF command is generated while the
High, Medium or Low command is still present at the input (this
turns the transmitter off if a type 1 fault occurs during turn-on).
When an “OFF” command is latched in Latch U42, the “OFF”
flip-flop’s output at U42 pin 2 goes HIGH. The “OFF” logic
signal is buffered by U43D, a two-input gate with its inputs tied
together so that it acts as a buffer-driver. The OFF command goes
to the B input (pin 10) of U50B, and the positive-going transition
triggers one-shot (monostable multivibrator) U50B. The oneshot’s Q output (U50B pin 5) goes HIGH and inhibits the
decoder. When the one-shot is triggered, a 2.4 second logic
HIGH pulse is generated at the Q output.
The Q output remains high during the one-shot’s time-out (2.4
seconds), unless a supply fault clears the one shot. The time-out
(pulse width) is determined by resistor R71 and capacitor C107
at U50B pin 7. If a Supply Fault logic signal is generated during
this time, it appears at U50B’s CLEAR input (pin 11) and
immediately clears the one-shot, causing the Q output to go
LOW again.
P.7.6.6 Decoder U40 Outputs
Only one decoder output can be active at a time, at the Y2
through Y7 outputs of U40. When any output is active (when the
command is present), that output is logic LOW. If no command
is present, all six outputs will be HIGH. Because commands are
only pulses (except for “Raise” and “Lower” commands), all
outputs will be HIGH most of the time.
Outputs to “Power Level Change” circuit: The OFF, HIGH,
MED, and LOW active LOW outputs from the decoder go
directly to 4-input OR gate U49B, which is the input of a “Power
Level Change” circuit (discussed later in this section). The
Power Level Change circuit generates a delayed pulse which
“strobes” the Power Level Data latches on the Analog Input
board.
P.7.6.7 Inverters (U41A through F)
All six Decoder outputs are inverted by the six sections of Hex
Inverter U41. When a command is present, then, the inverter’s
output is logic HIGH.
The inverter outputs for “Raise” and “Lower” commands go to
Up/Down Counter input gates. RAISE and LOWER commands
are active as long as the “Raise” or “Lower” button is held, or as
long as the remote command input is present, or when the VSWR
Induced Lower command is present.
Inverter outputs for Power Level commands (OFF, and HIGH,
MEDIUM, or LOW power) go to the Power Level Latch (U42).
The “Off” command also goes to Q4D’s input circuit. Any of
these commands are logic LOW signals, lasting as long as a
button is depressed or a remote control input is present.
P.7.7 “Power Level Change” Pulse
Each time a new Power Level Command is decoded, a delayed
“Power Level Change” logic LOW pulse is generated by this
circuit. This pulse clocks the Power Level Latch (U42) so that
the new power level is stored, and the pulse is also one of several
03/16/2009
P.7.7.1 Inhibit
A supply fault-L input to gate U49A inhibits the “power level
change” pulse.
P.7.7.2 Data Strobe
The Power Level Change pulse is “OR’ed” with other logic
signals in U45A (shown on sheet 2 of the schematic) to form the
Data Strobe pulse which clocks the digital power level data
latches on the Analog Input Board, A35. When a Supply Fault
occurs, the Power Level Change pulse is inhibited.
P.7.8 “Power Level Change Pulse” Circuit Descrip-
tion
This circuit includes U49B, U51A, U51B, U51E, Q4D, U49A.
Refer to Sheet 1 of the Controller board schematic diagram for
this description. The Power Level Change circuit is shown at
schematic grid locations D4, D5 and D6.
P.7.8.1 Input “OR” Gate (U49B)
The OFF, HIGH, MEDIUM and LOW logic LOW outputs from
the decoder are inputs to a four input NAND gate, U49B. When
any one of these commands is given, the output of U49B (at pin
8) immediately goes HIGH.
P.7.8.2 Delay (U51A, U51B, R128, C128)
The Data Strobe pulse to the Analog Input board is delayed about
20 milliseconds after the new power level Command occurs, to
ensure that the new power level data from the Controller is
present at the Analog Input board’s latch inputs.
During normal transmitter operation, or when the transmitter is
off, U49B’s inputs are all HIGH and its output is LOW. The
output of inverter U51A is then HIGH and C128 is charged to
U51A’s output voltage (nearly +5 volts). The voltage across
C128 is applied to the input of inverting Schmitt trigger U51B
(at pin 3), so that U59B’s output is LOW.
When an OFF, HIGH, MED, or LOW command input occurs,
one of OR gate U49B’s inputs goes LOW and its output goes
HIGH, forcing U51A’s output LOW. U51A then provides a
current sink and C128 begins discharging through R128 and
U49B’s output circuit. After about 20 milliseconds, the voltage
at inverting Schmitt trigger U51B’s input (pin 3) goes below the
trigger threshold and the trigger’s output goes HIGH.
At the end of the power level command pulse, the decoder
output, and the OR gate input, goes HIGH again. OR gate
U49B’s output goes LOW, inverter U51A’s output goes HIGH,
and capacitor C128 begins charging again. After about 20 milli-
888-2247-006
WARNING: Disconnect primary power prior to servicing.
P-15
seconds the voltage rises above inverting Schmitt trigger U51B’s
threshold, and U51B’s output goes LOW.
this logic LOW signal forces the NAND gate output HIGH,
inhibiting any Power Level Change pulse.
The output of U51B, then, is a logic HIGH pulse, like the one at
the decoder’s output except that it is inverted and delayed by
about 20 milliseconds. The pulse width depends on how long the
Power Level command input is held. U51B’s normal output (no
command present) is LOW.
The Power Level Change logic LOW pulse goes to the CLOCK
input of Power Level Latch U42, latching the new power level,
and also goes to OR gate U45 (shown on sheet 2 of the schematic
diagram) to generate a “Data Strobe” pulse.
P.7.8.3 “Power Level Change” Pulse Generator
This pulse generator includes R16, C108, inverting Schmitt
trigger U51E, and two inputs to NAND gate U49A. The pulse
generator’s input is the logic HIGH pulse at U51B, pin 4.
If ANY of NAND gate U49A’s inputs are LOW, its output, at
pin 6, will be HIGH. If ALL of the NAND gate inputs are HIGH,
the output will be LOW. During normal transmitter operation,
U51B’s output (pin 4) is LOW, forcing the NAND gate’s output
HIGH. The voltage across C108 is also LOW, so that Schmitt
trigger U51E’s output is HIGH.
About 20 milliseconds after a “power level” command, the
Delay output (U51B pin 4) goes HIGH. Now, all inputs of
NAND gate U49A are HIGH and its output goes LOW; this starts
the “Power Level Change - L” pulse.
Capacitor C108 begins charging to U51B’s “HIGH” output
voltage. After about 10 milliseconds, the rising voltage triggers
inverting Schmitt trigger U51E, and its output (pin 10), and
NAND gate U49A’s input (pin 4) go LOW. The LOW input
forces the NAND gate output HIGH again, and the “Power Level
Change -L” pulse ends.
Another “Power Level Change” pulse cannot start until C108 is
discharged. The capacitor does not begin discharging until the
Delay timer’s output (U51B pin 4) goes LOW, about 20 milliseconds after the power level command ends (the power level
command lasts as long as someone holds down a power button).
If an overload or other Type 1 fault occurs during this time,
another means of starting another “Power Level Change” pulse
is needed.
P.7.8.4 Transistor Q4D: Fast “OFF” Command
When a fault-induced OFF command occurs before the Power
Level change has been completed, Q4D initiates another “Power
Level Change” pulse as soon as the OFF command is given.
An OFF command, including fault-induced OFF commands, has
the highest priority, and when one occurs the Y7 output of
Decode IC U40 goes LOW. At inverter U41E’s output (pin 10)
there is a low-to-high transition, which is differentiated by
C122-R113-R114 (and the transistor’s input impedance). A
short positive going pulse is generated at Q4D’s base, the transistor conducts, and capacitor C108 discharges through the transistor. U51E’s output goes HIGH (and U51B’s output is still
HIGH) so that both pins 3 and 4 of NAND gate U49A are HIGH.
If there is no “Inhibit” at pins 1-2, the output of U49A goes LOW,
starting another Power Level Change pulse.
P.7.9 Power Level Latch (U42)
Normally, OFF, HIGH, MEDIUM and LOW commands are
short pulses. The Power Level Latch stores the power mode
information, that is, it “remembers” the last command. The
latch’s supply voltage is from the +5B memory backup supply,
so that the current “Power Level” information is still available
to restore transmitter operation after a power failure.
The outputs of Decoder U40 are active LOW. These outputs are
inverted by hex inverter U41, and the Power Level Command
signals become the Latch inputs. When a power level change
occurs, the high-to-low transition at the beginning of the Power
Level Change pulse (from U49A’s output, at pin 6) clocks latch
U42 and the new power level is stored in the latch.
P.7.9.1 Power Level Latch “CLEAR”
The power level latch is CLEARED only if the backup supply
voltage decreases to near the level where latch operation becomes unreliable and integrity of stored information would be
compromised. The latch is cleared (all outputs set LOW) if the
clear input goes LOW. The latch “CLEAR” input is a “RESETL” signal from the +5B Reset circuit (U66).
P.7.10 Latched “OFF” Command
When an “OFF” command is stored in latch U42, a logic HIGH
output appears at U42 pin 2. This output is buffered by U43D
(an AND gate used as a logic buffer), and goes to:
a. The trigger input of “Decode Inhibit” one-shot U50B (the
one-shot’s output pulse inhibits the decoder for 2.4 seconds, preventing transmitter turn-on during that time).
b. “Inhibit K2" NOR gate U53C (pin 11) (in the turn-on/turnoff control logic). This de-energizes the high-voltage supply contactors.
When the “Off” command is latched, the HIGH, MEDIUM and
LOW latched outputs are all logic LOW, the multiplex address
lines are all LOW, all multiplex outputs go to th