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UNIVERSAL HORIZONTAL
ANALYZER (HA2500) TRAINING
HA2500 Universal Horizontal Analyzer
Universal Horizontal Analyzer Tests
Load Test checks
H.output -chassis
off
Dynamic Hoirz
Output Meter
Test output current
from H. Driver stage
Substitute
B+ voltage
to Horiz.
Output stage
Load Test &
Sub Drive
Frequency
Adjust
Ringer Test
Detects shorted
turn in IHVT,
yokes, coils
Substitute H.
Drive to Horiz.
Output Transistor
HORIZONTAL STAGES IN HI-RESOLUTION
CRT VIDEO DISPLAYS
1. Horizontal Output - Produces current in flyback and/or
yoke resulting in HV and/or deflection
2. B+ Power Supply - Powers horizontal output & driver stages
with voltage ranging 30-190 volts.
3. HV/Deflection Regulator - Varies B+ to horizontal output
to keep HV and/or deflection constant.
4. Horizontal OSC/AFC - Generates sync-locked drive at the
horizontal scanning frequency.
5. Horizontal Driver Stage - Amplifies weak drive to level
needed by the horizontal output transistor.
6. X-Ray Shutdown - Disables horizontal output stage by
removing drive or B+ when the HV is at an unsafe level.
Basics of Horizontal Output Stage
Horizontal Output Stage in Multi-Resolution CRT Video Display
Horizontal Output Stage in Hi-Resolution CRT Video Displays
Horizontal Output Stage Types In Hi-Resolution CRT Video Displays
S-Capacitor and Linearity
Coil Switching
H. Deflection
Regulated B+
T503
Q519
HST +
D511
Horiz. Drive
H. Yoke
C538
HLC
Linearity Coil
L506
+ 15 V
S-Capacitors
Select
C523
Q518
Q520
Q522
Q523
Q527
Q524
C554
Switched by mode control as horizontal
scanning frequency (resolution) increased.
2.2uFd
Understanding Horizontal Troubleshooting Difficulties
Technicians indicate more than 50% of failures are horizontal related.
* Excessive horizontal current (loading) decreases the SMPS output
voltage (limiting) or damages SMPS circuitry.
* Excessive horizontal output current stresses or burns out, HOTs,
HV/defl. Regulator & SMPS components.
* A flyback or horiz. yoke shorted turnor flyback secondary circuit
short cause excessive current (loading) not evident with ohmmeter.
* HV/deflection regulator interacts with horizontal output stage.
* Horiz. Drive defects cause horizontal output transistor heating
often resulting in failures.
* Flyback pulses feed back to AFC, these circuit loops can cause
unusual drive and picture symptoms.
* X-ray shutdown results in momentary operation with no effective
means to make measurements to isolate the cause.
HA2500 Universal Horizontal Analyzer Features
* Chassis Off Horizontal Output Stage Load Test: Isolates
defects with power off (PS loading, shutdown, HOT burn outs).
* Dynamic Horizontal Output “METER”: Tests output operation
& finds horizontal drive and B+ supply problems.
* Exclusive Horiz Driver Test: Measures driver stage output
current- detects weak drive or intermittent drive.
* Horizontal Output Transistor Base or Gate Sub Drive:Subs
missing or suspect drive to prove output stage good or bad.
* Substitute B+ Power Supply: Subs chassis B+ supply to isolate
SMPS, HV/Defl. Regulator, X-ray, or output stage.
* Flyback, Yoke & Coil Ringer Tester: Determines is component
good or bad from a shorted turn(s).
Horizontal Output Load Test Introduction
Provides a functional test of the horizontal output stage at the proper
frequency & 1/10th B+ voltage to detect loading (high B+ current) and
defects that do not permit power on testing.
Benefits:
Identify horizontal output stage defects before replacing
and burning out replacement output and P.S. parts.
Quickly determine if horizontal output stage defects
exist before applying AC voltage.
Determine if the horizontal output stage is the cause
of PS defects or improper operation.
Block Diagram of Load Test and
Connections To Horiz. Output Stage
Orange clip to B+ Input to Flyback
Yellow clip to Collector of H.O.T.
Black clip to Horiz. Circuit Ground
Load Test Setup
Load Test Setup
Guides you to setting frequency & 1/10 B+ voltage to test the horizontal
output stage. Confirms proper load test with VPP readout.
1. Remove AC to chassis - start with LOAD TEST B+ VOLTS at “MIN.”
2. Connect the LOAD/RINGER test leads to proper chassis points.
3. Set the LOAD & RINGER TEST Switch to “LOAD TESTS SETUP.”
4. Set the HORIZONTAL FREQUENCY COARSE and FINE Controls
for a frequency near the displays highest horizontal scanning frequency.
5. Increase the LOAD TEST B+ VOLTS Control to approximately 1/10 of
the normal B+ to the horizontal output stage.
6. Read the VPP readout - 1/10 of normal - 100VPP typical.
Load Test Connections & Readouts
ANALYZING THE HORIZONTAL OUTPUT STAGE
Load Tests Readouts
Interpreting Load Test Readings
Typical uS range or horizontal pulse times for
multi-frequency (resolution) video displays.
A display’s pulse time should be in the range of its highest
horizontal scanning frequency or scan format capability.
Relationship of
flyback pulse to
horizontal blanking
interval in underscan and overscan displays.
Horiz. Flyback
pulse is retrace
time which occurs
during video horiz.
blanking interval.
Ringer Test
Provides a test to determine if the flyback
or yoke has a shorted turn defect.
* Confirms if flyback, yoke or coil must be replaced.
* Saves time replacing components and doing added
testing to determine flyback, yoke or coil is defective.
* Proves the flyback, yoke or coil does not have a shorted
turn and repair is likely feasible.
Ringer Test
Ringer Test Detects Shorted Turns
To Ringer Test a Flyback
1. Remove AC to the chassis
2. Set the Load & Ringer Tests Switch to “Yokes & Flybacks.”
3. Connect the Ringer/Load Test leads to the primary winding.
(Use the orange and black test lead clips)
4. Read the rings indicated by the HA2500 center display.
Note: 10 or more rings indicates the flyback does not have
a shorted turn. Rings less than 10 indicate a shorted turn.
DYNAMIC TESTS - METER
Provides automatic
measurements at horizontal
output transistor to ID
horizontal drive,
B+ supply or horizontal
output stage symptoms
and defects.
Check horizontal drive VPP and Freqeuncy.
Check for missing or improper B+ volts.
Check for horizontal output stage flyback
pulse VPP.
Check flyback pulse time in uS automatically.
Collector Or Drain METER Readouts
Base Or Gate METER Readouts
To Use the Dynamic Tests Meter
1. Remove AC to the chassis
2. Connect the Dynamic Tests Leads
3. Set the Dynamic Tests Switch to “Collector Or Drain.”
4. Apply AC to the chassis.
5. Read the DCV, VPP and uS readouts in the center display.
6. Set the Dynamic Tests Swtich to “Base or Gate.”
7. Read the kHz and VPP readouts in the center display.
Horizontal Driver Test
A measurement of the output current capability of the horizontal
driver stage. The test simulates a base/emitter HOT junction and
measures output current during positive drive cycle.
Benefits
* Determines if the base drive current is adequate for normal HOT function.
*Indicates when driver stage is suspect of HOT heating or repeat failures.
* Displays drive current to ID intermittent drive defects without damaging
replacement horizontal output transistors.
HORIZONTAL DRIVER & OUTPUT STAGE
The horizontal driver stage produces output drive current
to the base/emitter junction of the horizontal output stage.
Defects reduce this current causing H.O.T. heating, failures
and improper horizontal output stage operation.
Methods used to control driver stage output current
with horizontal scan frequency changes.
Adjust V+ to
Driver Stage
Switch resistance
in base of H.O.T
Horizontal Driver Test - Push & Hold Red Test Button
How To Perform the Horiz. Driver Test
1. Remove AC voltage - unsolder
H.O.T. base or open base circuit path.
2. Connect Dynamic Test Leads
3. Set DYNAMIC TESTS Switch to
“HORIZ. DRIVER TEST.”
4. Apply AC voltage to chassis - Push
Power switch to ON.
5. Push & Hold the HORIZ DRIVER
TEST OR SUB DRIVE Pushbutton.
6. Read the mA reading & compare
to typical mA range chart.
Block Diagram of Horiz. Driver Test
Base Sub Drive & Gate Subdrive
Provides substitute horizontal
drive, optimized to drive
the base (bipolar output)
or gate (MOSFET output)
transistor.
Subs for missing or suspect horizontal drive to test the
horizontal output stage or to isolate subtle reduced deflection,
noises or unusual picture horizontal tearing defects.
Display Before & During Base or Gate Sub Drive
Be sure Frequency
matches signal source.
Be sure B+ voltage
is proper or regulated.
During Subbing
collector DCV, VPP
puse uS readings are
displayed.
Substitute Horiz. Drive To The Base or Gate of Horizontal
Output Transistor (Base -Bipolor, Gate - MOSFET)
Block Diagram of HA2500 Base Sub Drive
Output drive current is dynamically adjusted.
Gate Sub Drive Block Diagram
To Substitute Base Drive to the
Horizontal Output Transistor (Bipolar)
1. With AC power removed unsolder the Horiz. Output
transistor base or open base circuit path.
2. Connect Dynamic Test Leads - Blue to base of H.O.T.
Yellow to H.O.T collector, Black to Horiz. Ground.
3. Set the Dynamic Test Swtich to “Base Sub Drive.”
4. Apply AC to the chassis and read the DCV readout to
confirm proper B+.
5. Read the display kHz readout to confirm the proper
drive frequency.
6. Push & hold the Horiz. Driver Test or Sub Drive push button.
7. Read the DCV, VPP and uS readouts to test the horizontal
output stage.
Note: Proper readings indicate normal output stage operation.
Synced With Generator A Locked Picture Appears
SUBSTITUTE B+ SUPPLY
A variable DCV power supply to substitute for the B+ voltage
to the horizontal output stage or to the HV/Deflection regulator.
Determines if the horizontal output stage is good or bad by subbing
for a dead or suspect B+ power supply.
Isolates defects to B+ supply, regulator, or horizontal output stage.
Permits slowly increasing B+ voltage to isolate HV breakdown
failures, troubleshoot current shutdown and regulation defects.
Isolate X-ray or HV shutdown symptoms.I
Typical B+ Voltage Path In Multi-Frequency CRT Display
Using The Substitute B+ Supply
To Substitute B+ Voltage To a Horizontal Output Stage
1. Remove AC to the chassis and open a jumper wire, coil
or resistor in the B+ power supply path to the flyback.
2. Set the HA2500 VOLTS Control to “off” and the POWER
LIMIT control to 1/2 scale (40W).
3. Connect the B+ Supply Leads to the chassis.
4. Connect the Dynamic Test Leads to the chassis horizontal
output transistor.
5. Set the Dynamic Tests Switch to “Collector Or Drain.”
6. Apply AC Power to the chassis.
7. Increase the VOLTS Control to apply substitute B+ volts.
(Increase the B+ sub voltage until the Collector Or Drain
meter indicates normal VPP for the chassis)
B+ Substitution to the Input of HV/Deflection Switching Regulator
Using the Substitute B+ Supply and Sub Drive Together
Congratulations- You are now an experienced
Universal Horizontal Analyzer (HA2500) User!