Download 1. INTRODUCTION

1.
INTRODUCTION
1.1
General Description
1.2
Accessories
1«3
Technical Specification
1.1
General Description
The LKB Novaspec is designed as a simple to operate instrument
capable of producing rapid measurement of light absorption or
transmission in the visible spectrum. Ease of operation is
achieved by using a microprocessor to perform most of the
repetitive tasks usually requiring prolonged operator action.
The instrument is shown in Fig. 1.1 below.
Display Panel
Sample Compartment
Cover
Key Pad
Fig. 1.1: General View
The instrument is capable of performing absorbance measurements in
the ranges -.30 to .999A and -.30 to 1.99A, and measurement
directly in transmission units with an operational wavelength
range of 325nm to 900nm. All operator inputs are made using four
keys which comprise the operator key pad. A display panel mounted
at the top of the unit provides instrument status information and
digital displays of the selected wavelength and the measurement.
Samples can be inserted into the instrument in 24mm (1") test
tubes, 12mm (1/2") test tubes or 10mm cuvettes - the latter two
requiring the use of the removable small test tube cuvette holder.
The sample compartment is covered by a removable light tight lid.
1.2
Accessories
A range of accessories is available for the LKB spectrophotometer
as described below:
Standard 10mm rectangular cells
Tall series 10mm rectangular cells
Funnel flowcell
24mm (1") and 12mm (1/2") test tubes
Spectral light pipe for educational use
External sample compartment cover for use with long test tubes
(i50mm)
Chart recorder.
1.3
Specification
The instrument specification, is described below:
Monochromator:
1200 lines/mm holographic
diffraction grating
Wavelength Range:
325-900nm
Wavelength Calibration:
Automatic upon switch on
Wavelength Accuracy:
*2nm
Wavelength Reproducibility:
*1 nm
Light Source:
Tungsten Halogen Lamp
Detector:
Single solid state silicon
photocell
Spectral Bandwidth:
12nm
Stray Light:
\% at 340nm measured
according to ANSI/ASTM
E387-72
Photometric Stability:
0.004A/Hr after warm up
Photometric Noise:
+0.001A near OA at 600nm
Photometric Ranges:
-.30 to .999A
-.30 to 1.99A
1.0 to 200$T
Sample Compartment:
Complete with removable small
test tube and cuvette holder.
Accommodates 24mm (1 ") test
tubes, 12mm (1/2") test tubes
standard and tall 10mm
Data Output:
0-1V for O - U .
C O Sf-'T $ ? N T S •-;•
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' 1.1 '=
General- - B e s c r i p t i o n
' J 1 • ^ ? AccessoTies
•'•
2.
1.5
T echnie a I'^Sy&c if i ca t i on
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Amt&matie Vavelength .C^
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Kon Calibr&tion
2.4.1
Failure at Cal 1
2.4.2
lailure at Cal 2
•5.--I ':; SSÜÏOKBTER
General DeacriptiQa
.Slectronlo PescriptiW
getting Up Procedure
Circuit Diagrams
Parts List
IC Pin -Outfl
PN4156-0184 Eöl *3/85
4.
MAIH PCB
4.1
General Description
4.2
Electronic Description
4.3
5.
4.2.1
Microprocessor
4.2.2
The Analogue to Digital Converter
4.2.3
Recorder Output
4.2.4
Programmalle I/O
4.2.5
Program Memory
Adjustments
4.3.1
A/D Ref. Voltage
4.3.2
Recorder Output
4.4
Circuit Diagrams
4.5
Parts List
4.6
IC Pin Outa
POWER SUPPLY PCB AND LOOM
5.1
General Description
5.2
Electronic Description
5.2.1
Tungsten Lamp Supply .
5.2.2
5V Logic Supply
5.2.3
-5V Supply
5.3
Tungsten Lamp Adjustment
5.4
Circuit Diagrams
5.5
Parts List '
5.6
IC Pin Puts
5.7
Loom Wire Run Outs
.
,
6.
DISPLAY PCB, KEYBOARD PCB
6.1
General Description
6.2
Electronic Description
6.2.1
Display PCB
6.2.2
Keyboard PCB
6.3
Adjustments
6.4
Circuit Diagrams
6.5
Parts List
6.6
IC Pin Outs
MAINTENANCE
7.1
Introduction
7.2
Safety Notes
7.3
Special Rote About The Monochromator
7.3.1
7.4
Fault Finding
7.4.1
7.5
Cleaning of the Optical System
Trouble Shooting Table
Mechanical Servicing
7.5.1
Removal of Top Cover
7.5.2
Removal of Wain Chassis
7.5.3
Replacement of Fan
7.5.4
Lamp Output Check
7.5.5
Tungsten Lamp Replacement
7.5.6
Drive Cord Replacement
8.
OPERATION
8.1
8.2
8.3
ÏBtroduction
8.1.1
Key Pad
8.1.2
Display Panel
8.1.3
Sample Compartment
Instrument Operation
8.2.1
Initial Switch-On
8.2.2
Performing a Measurement
Further Operator Information
8.3.1
Introduction
8.3.2
Instrument Indications
2.
DESCRIPTION OF OPTICAL SYSTEM
2.1
Light Source
2.2
Optical System for 4049
2.3
Automatic Wavelength Calibration
2.4
Reasons for Non Calibration
2.1
2.4.1
Failure at Cal 1
2.4.2
Failure at Cal 2
Light Source
The light source is a single 12V tungsten lamp operating at 10.2V
to increase lamp life. The lamp can easily be replaced without
the removal of the instrument main cover.
2.2
Optical System for 4049
The instrument optical system is shown in simplified form in Fig.
2.1. The light output from the lamp passes through a slit to the
collimator where it is converted into a single parallel beam.
This light is then passed to the monochromator which contains the
diffraction grating and the stray light filters. The diffraction
grating in conjunction with the second collimator produce the
monochromatic light which passes through the sample to the soiid
state detector unit.
\
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MONOCHROMATOR
1
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DIFFRACTION
GRATING
W
STRAY
LIGHT
FILTERS
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,
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Fig. 2.1: Optical System
i
2.3
Automatic Vavelength Calibration
Upon switch on Cal 1 appears on the display. During Cal 1 the
grating arm is being driven to the backstop opto switch position.
Upon recognition of the opto signal, the display shows Cal 2 and
the grating motor reverses. The instrument now searches for its
calibration peak, the zero order spectrum.
Upon identifying the centre point of this peak, the instrument
changes to Cal 3 and the grating motor drives to 360nm. During
this period the darking solenoid actuates and the dark current is
stored.
2.4
Reasons for Kon Calibration
2.4.1
Failure at Cal 1
This is due to either failure of opto switch or the
breaking or disconnection of Drive Cord or a malfunction of
the grating motor or associcated drive circuit. Failure is
signified by staying on Cal 1.
2.4.2
Failure on Cal 2
This could be due to lamp failure, sample left in cell
compartment, total misalignment of the opties. Failure is
signified by automatic return to Cal 1 and display flashes.
When calibrated the instrument should read >.999A, if not
the lamp has moved or is faulty.
3.
PHOTOMETEE PCB
3.1
Specification
3«2
General Description
3-3
Electronic Description
3-4
Setting Up Procedure
3-5
Circuit Diagrams
3-6
Parts List
3.7
IC Pin Puts
3.1
Specification
Photodiode detector.
OV to -4V de signal voltage output from 2 bit Programmable Gain
Amplifier.
Programmable gains of 1, 4, 16, 64.
Gain ratiometric accuracy corresponding to 0.001A = 0.23$
+/- 5V supply.
3«2
General Description
The circuit diagram is given in Section 3-5. A conventional
photodiode front end stage similar to the Ultrospec II is used,
but with less current to voltage gain and hence lower impedances.
The lower supply voltages available make the Harris amplifier
unsuitable for this application and so the Texas TLC271CP was
chosen for its wide common mode input voltage range and low offset
current. The amplifier is operated at the medium bias setting
(pin 8 = OV) giving the best trade-off between open loop gain and
noise. The programmable gain amplifier is another TLC271CP with a
high accuracy pot chain made from discrete resistors and the
appropriate tapping selected from a low cost CMOS multiplexer.
3.3
Electronic Description
The photocurrent produced by light hitting the photodiode is
converted by 1201 into a voltage proportional to the impinging
light. Offset pot (R204) and gain pot (R208) are provided to
control photodiode bias and to ensure that the amplifier does not
saturate under maximum light levels (gain pot set to give -3V max
output). The offset pot is adjusted under no light conditions so
as to apply a small negative bias of 2mV across the photodiode.
This is done to guarantee that the diode will not become forward
biased even if the amplifier input offset voltage drifts with
temperature in a positive direction. Thus the output from the
first stage varies from -2mV under no light conditions to -3V
under maximum light conditions.
The second stage comprises the programmalle gain amplifier (1202).
A 2 bit binary input to the multiplexer is used to select one of
four possible gains, 1, 4, 16 and 64 by switching in the
appropriate section of a precision divider ladder. An offset
adjustment pot (R210) is provided to null the amplifier output
when a gain of 64 is selected and there is 0V input. This
prevents any amplifier input offset voltage from being gained up
by the feedback resistors.
3.4
Setting Up Procedure
There are three potentiometers on this PCB. The offset pots R210
and R204 are factory set and do not need adjusting. R208 is the
gain pot and will only need adjusting if the lamp intensity
changes greatly. This may happen if a new lamp is very much
brighter than the old one.
5
Circuit Diagrams
4000 4574
Photometer Circuit
4000 4576
Component Overlay
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z
in
o
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n
R20G
R205
f3
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B
40004575
ISS 1 SIDE 1
LKB
OD
:
RS10
CS06
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RS07
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R204
CD
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RS19
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RE 16
RS15
R213
RSil
RE14
RS12
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REOe
3-6
Parts List
Photometer PCB
Quantity
Part Nummer
Description
Location
4000 4575
Photometer PCB
A3
4000 4574
Photometer Circuit
A3
4000 4576
Component Overlay
1
4187 0102
1
4178 0092
10 Way Dual Row Rt. Angle
Waf er
Photodiode UV50
2
4181 0097
Integrated Circuit
TLC271CP
IC201, IC202
1
4181 0094
Integrated Circuit
CD4O52B
IC2O3
1
4160 0277
Resistor 100R \% Metal
Film
R201
2
4160 0080
Resistor 1K \% Metal Film
R2O9, R218
3
4160 0022
Resistor 10K \% Metal Film
R2O5, R206,
R207
1
4160 0321
Resistor 90.OK \% Metal
Film
R215
1
4160 0322
Resistor 147K \% Metal
Film
R213
1
4160 0323
Resistor 332K \% Metal
Film
R211
2
4160 0125
1
4160 0181
Resistor 1K5 \% Metal Film R219
1
4160 0324
Resistor 100R 0.1$ Metal
Film
R217
1
4160 0325
Resistor 301R 0.1$ Metal
Film
R216
1
4160 0326
Resistor 121OR 0/1 # Metal
Film
R214
1
4160 0327
Resistor 4870R 0.1$ Metal
Film
R212
1
J201
D201
Resistor 4M7 5% Metal Film R202, R203
Quantity
Part Number
Description
Location
4162 0098
Capacitor 100pF Ceramic
100V
C202, C2O7
4162 0099
Capacitor 10nF Ceramic
100V
C201
4162 0100
Capacitor 100nF Ceramic
50V
C203, C204,
C205, C206
4163 0008
Capacitor 10uF
Electrolytic 50V
C208, C2O9
4161 0030
Trimpot 20K 25 Turn
R204, R208,
R210
3-7
IC Pin Outs
TLC271CP Programmable Low Power Op Amp
BIAS
SELECT
V
M
OUTPUT
DD
OFFSET
NULL (NO)
\ï~\
1
OFFSET
NULL (NI)
INV NON-INV
INPUT INPUT
GND
CD4052 H Channel Analogue Multiplexer/Demultiplexer
IN/OUT
'-~*-N
'DD
16
1
2x
OUT/IN
lx x
IN/OUT
'~^->
Ox 3x
15
14
13
12
2
3
4
5
Oy 2y y 3y ly
V v >
~~
OUT/IN
^"^
IN/OUT
IN/OUT
TOP VIEW
11
6
INH
A
B
10
9
7
8
MAIN PCB
4»1
General Description
4.2
Electronic Description
4.3
4.2.1
Microprocessor
4.2.2
The Analogue to Digital Converter
4.2.3
Recorder Output
4.2.4
Programmable I/O
4.2.5
Program Memory
Adjustments
4.3.1
A/D Ref. Voltage
4.3.2
Recorder Output
4.4
Circuit Diagrams
4-5
Parts List
4.6
IC Pin Outs
4.1
General Description
The main PCB contains the microprocessor based control system of
the whole instrument. This board outputs signals to the display
board, the keyboard, the photometer board, the grating motor, the
analogue output and the darking flag solenoid. It also processes
inputs from the keyboard and the photometer board.
4.2
Electronic Description
4.2.1
Microprocessor
An Intel 8085 controls the entire instrument. All
functions are pontrolled via the buses, and 1111 decodes
the three highest address bits to provide the chip select
signals. Timing for the 8085 is derived from a 4.433 MHz
crystal.
4.2.2
The Analogue to Digital Converter
The A/D converter is an Intersil ICL71O9, which is a 12 bit
binary, dual slope integrating A/D converter, with low
noise and drift characteristics.
The end of conversion is checked by the status line from
the converter to the input port of 1116. When the status
is high, 1109 is still converting and when the status is
low, the data is valid for reading. Each reading made by
the converter consists of three cycles:a)
Auto-zero Sequence
Auto-zero disconnects the internal inputs and shorts them
together. A reference capacitor is charged to the
reference voltage and an auto zero capacitor is also
charged. This compensates for offset voltages, so that the
output level will be zero input. The reference voltage is
set at 0.800V.
b)
Signal Integrate Phase
The signal integrate phase connects the input signal for
measurement to the internal amplifier, which has been
offset corrected and also charges capacitor C119 for a
period of 2048 clock counts.
c) De-integrate Phase
De-integrate causes the internal amplifier to be
disconnected from the signal input and then connected to
the reference capacitor, which causes the output of the
amplifier to return to zero volts. The time taken from
start of de-integrate until zero is reached, is therefore
proportional to the input voltage and this is counted
against the system clock (normally a maximum of 4096
counts).
The A/D runs independently from the microprocessor and
receives its timing from the 8253 counter/timer 1113'
4.2.3
Recorder Output
For recorder output, 1113 provides a pulse train whose mark
space ratio varies with the desired output signal from the
detection system. 1113 is a 8253 programmable interval
time/counter.
1114 accepts the pulse train from 1113 and provides drive
current to charge the two pole filter network on the input
of 1115. 1115 acts as a buffer amplifier to drive the
analogue output. The output level is set by V121 and the
output is provided at two 4mm sockets on the rear of the
instrument.
4.2.4
Programmable I/O 1103
Port A
Bit 0.
1
2
3
4
5
6
7
Stray light solenoid control bit (unused)
Darking Flag control bit
6 display digits
and indicator LED
refresh bits
)
)
Keyboard Scan
bits
Port B
Bit 0
1
2
3
4
5
6
7
Display Segments
refresh bits
Port C
Bit 0
1
2
3
4
5
4.2.5
)
) Grating Motor
) drive
)
) Photometer gain
) control bits
Program Memory
The instrument control program is contained in a 2764
EPROM, 1112. This device contains 64K bits or 8K bytes of
ROM. The RAM memory of the system, consisting of only 256
bytes, resides in the 8155 chip, 1103.
4.3
Adjustments
4.3.1
A/D Ref. Voltage
The voltage between TP1 and TP2 should be adjusted by means
of V114 to 0.800V. V114 is on the main PCB.
4.3.2
Recorder Output
The voltage at the recorder output terminals should be
adjusted by means of V121 to give 1V per 1A e.g. if the
display reads .695A, then adjust output to give O.695V.
V121 is on the main pcb.
4.4
Circuit Diagrams
4000 4560
Control Circuit Diagram
4000 4562
Component Overlay
4«5
Parts List
Main PCB
Quantity Part Number
Description
Location
4000 4561
Control PCB
A1
4000 4560
Control Circuit Diagram
A3
3
4160 0013
Resistor 1 OK
R11 0,109,114
1
4160 0015
Resistor 22K
R111
2
4160 0006
Resistor 1K
R112,122
1
4160 0094
Resistor 4K7
R106
1
4160 0112
Resistor 1 80R
R108
1
4160 0275
Resistor 270K
R124
2
4160 0071
Resistor 15K
R123,113
4
4160 0103
Resistor 100K
R115,117,118
119
1
4160 0146
Resistor 39OR
R120
1
4160 0269
Resistor 1 50K
R116
1
4161 0060
Potentiometer 500R
V121
1
4161 0058
Potentiometer 1 OK
V114
1
4181 0019
Integrated Circuit
8085AH
1108
1
4181 0047
Integrated Circuit
8155AH
1103
1
4181 0042
Integrated Circuit
ICL7109
1109
1
Part Number
Description
Location
1
4181 0014
Integrated Circuit
74LS373
1110
1
4181 0043
Integrated Circuit
ULN2803A
1101
1
4181 0017
Integrated Circuit
74LS138
1111
1
4181 0010
Integrated Circuit
8253
1113
1
4181 1000
Integrated Circuit
74LS00
1107
1
4181 3140
Integrated Circuit
CA3U0E
1115
1
4181 4069
Integrated Circuit
MC4069UB
1114
1
4181 0089
Integrated Circuit
74LS365
1116
1
4181 0008
Integrated C i r c u i t 78L05
1104
1
4000 4927
Control Eprom A
1112
1
4174 0001
Crystal 4.433 MHz
10
4162 0100
Capacitor 0u1
C123-C132
2
4162 0093
Capacitor 22pF
C113-C114
1
4162 0074
Capacitor 1uF
C116
1
4162 0070
Capacitor 0.22uF
C104
1
4162 0071
Capacitor O.33uF
C118
1
4162 0072
Capacitor O.47uF
C117
1
4162 0066
Capacitor 47nF
C119
1
4163 0000
Capacitor 0.47uF
C105
2
4163 0002
Capacitor 1 uF
C120,C121
1
4163 0008
Capacitor 10uF
C122
1
4163 0011
Capacitor 47uF
C115
1
4178 4148
Diode IN4148
D101
Quantity
6 IC Pin Outs
8O85A
40 Z ]
vcc
39 Zl
HOLD
AD2
EZ 1
EZ 2
LZ 3
LZ 4
EZ 5
EZ 6
IZ 7
EZ 8
LZ 9
EZ 10
EZ 11
LZ 12
EZ 13
EZ 14
AD3
tz
15
26 Z l
A
13
AD4
25 Z ]
A
12
AD,
LZ 16
IZ 17
24 Z l
A
cz
ll
AD6
23 Z l
A
24
v
x
l
x2
RESET OUT
SOD
SID
TRAP
RST 7 . 5
RST 6 . 5
RST 5 . 5
INTR
TNTA
ADQ
AD1
b
38 Z3 HLDA
37 Zl
CLK (OUT)
36 ZJ RESET IN
35 Z3 READY
34 Zl
33
18
z:
IO/M
S
32 Z ]
l
ÏÏD
31 Z l
WR
30 Zl
ALE
29 Zl
S
28 Zl
A
15
27 Z ]
A
14
0
10
22 Z3 A9
21 Z l A
8
LZ 19
20
V
SS EZ
AD7
8253
7 IZ
D
1
2
6 EZ
3
D
5 EZ
LZ 4
D
4
5
D
3 EZ
LZ 6
D
2
D
LZ 7
D
l
V.y
23
22
21
20
19
18
8
0 LZ
CLK 0 EZ 9
16
OUT 0 LZ 10
15
GATE 0 LZ 11
14
GND LZ 12
13
D
Zl
Zl
Z1
Zl
Zl
17
Zl
Zl
Zl
Zl
Zl
cc
WR
ÏÏD
er
A
l
A
o
CLK 2
OUT 2
GATE 2
CLK 1
GATE 1
OUT 1
8155/H
8156/H
8155H-2/
8156H-2/
PC
40
3
'CC
PC4
CZ 2
39
TIMER IN
3
38
RESET
4
37
PC5
5
36
TIMER OUT
6
35
IO/M
7
34
E T OR CE
8
33
RD
9
32
W
10
31
11
30
PB ]
12
29
PB (
13
28
PA-
AD O
14
27
AD
15
26
16
25
17
24
18
23
19
22
20
21
ALE
EZ
ADQ
AD ]
AD'SS
CZ
CZ
CZ
CZ
L
=1
Z3
2
PC
PC C
PB
m
PB
PB,
PA,
PAr
4069
ïï.
'SS
CZ 1
CZ 2
CZ 3
CZ 4
CZ 5
CZ 6
CZ 7
^_y
14 Z3
'DD
13 Zl
12 Z]
.
11 Zl
10 ZJ
9 ZI
8 Zl
ÏÏ,
ICL71O9
cz
1
40
d
d
2
39
3
38 Zl REF CAP-
LZ 4
d 5
37 Z ] REF CAP+
36 Zl REF I N +
Bil
cz
6
35 Zl I N H l
B1O
tz
7
34 Z l I N LO
d
B8 d
B7 d
B6 LZ:
B5 d
B4 d
B3 d
B2 d
BI d
TEST d
LBËN d
ÏÏBËN d
CE/LOAD
d
8
33 Z ] COMMON
9
32 Zl INT
10
31 Zl AZ
11
30 =1 BUF
12
29 Z l REF OUT
13
28
14
27
15
26 Z3 RUN/HÖUÏÏ
16
25 Z ] BUF OSC OUT
17
24 Z3 OSC SEL
18
23
19
22 Z ] OSC I N
20
21 Z3 MODE
GND
STATUS
POL
OR
BI 2
B9
OFFSET NULL
INVERTING INPUT
NON-INTERTING INPUT
Zl
Zl
V+
REF I N -
V-
Z3
Zl
SEND
OSC OUT
7^365
CL
16 V-CC
m
ï?
T
GND [ V
10
5.
POVER SUPPLY PCB AND LOOM
5.1
General Description
5.2
Electronic Description
5.2.1
Tungsten Lamp Supply
5.2.2
5V Logic Supply
5.2.3
-5V Supply
5.3
Tungsten Lamp Adjustment
5.4
Circuit Diagrams
5.5
Parts List
5.6
IC Pin Outs
5-7
Loom Wire Run Outs
5.1
General Description
The power supply PCB rectifies the a.c. supplies from the
transformer to provide the d.c supplies required for instrument
operation.
5>2
Electronic Description
The power supply consists essentially of three sections.
5.2.1
Tungsten Lamp Supply
The tungsten lamp supply of 10.2V d.c. is derived from a
13.5V winding on the transformer. The regulator for this
supply is an SGS L200 linear device mounted remotely on the
fan bracket. This is because the L2OO generates a
considerable amount of heat which must be dissipated from
the instrument enclosure.
5.2.2
5V Logic Supply
The second section consists of the 5V logic supply via a
78S05 regulator and a 9V unregulated supply for the display
drivers, the grating motor and the darking flag solenoid.
A 9V a.c. supply is tapped off before the rectifier REC2 to
drive the fan.
5-2.3
-5V Supply
The third section is a -5V supply via IC3, a 79LO5
regulator, for the A/D converter, the photometer amplifiers
and the, analogue output driver.
Note
The +5V supply, denoted +5V(A), for the A/D converter,
photometer amplifiers and the analogue output driver, is
generated on the main PCB via 1104, a 78LO5 regulator, from
the 9V unregulated supply. It is located on the main PCB
because it needs to be physically close to the A/D
converter to minimise noise pickup on the supply. The
reference voltage on the A/D converter should be as quiet
as possible.
5-3
Tungsten Lamp Adjustment
This is 10.2V measured on the terminal strip and adjusted by R2
mounted on the power supply board.
5«4
Circuit Diagrams
4000 4569
Power Supply Circuit Diagram
4000 4571
Component Overlay
LKB
S
HËCl
RECS
R
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POWER SUPPLY PCB ASSY 40004571
5.5
Parts List
Power Supply PCB and ]Loom
Quantity
Part Number
Description
Location
4000 4570
Power Supply PCB
A3
4000 4569
Power Supply Circuit
A3
2
4178 0029
Rectifier KBL02
REC 1 ,REC 2
1
4178 0013
Rectifier W01
REC 3
4
4163 1070
Capacitor 4,700uF 25V SU
C1 ,C12,C5,C6
1
4163 1071
Capacitor 1,CO0uF 25V SU
C9
2
4163 0000
Capacitor 0u47 K Series
C8.C11
3
4162 0070
Capacitor 0u22 MKS2
C2,C7,C10
1
4162 0068
Capacitor 0u1 MKS2
C4
1
4163 1034
Capacitor 100uF 25V
C3
2
4163 0011
Capacitor 47uF K Series
C13,C14
1
4160 0104
Resistor 820R
R1
2
4160 0094
Resistor 4K7
R3.R4
1
4161 0026
Potentiometer 10K
R2
1
4181 0091
Regulator 78S05
IC2
1
4181 0055
Regulator 79LO5
IC3
1
5.6
IC Pin Outs
100 mA fixed voltage
pin view
pin view
Fixed-voltage 100 mA regulators with internal, overload, thermal and shortcircuit protection TO92 plastic case. Total dissipation 600 mW at T
25 C.
5-7
Loom Wire Run Outs
Control Board Connector J100
Pin
Number
Signal Name
Wire Colour
Destination
1
Motor 0 2
YL/REL
Motor 2
2
Motor 0 1
RD/BRN
Motor 1
3
Motor 0 3
RD/BK
Motor 3
4
5
Recorder +
Motor 0 4
OR/BL
RD/GRN
Conn Block Row 8
Motor 4
6
+5V (A) Output
WH/YEL
Photometer J201
Pin 3
7
Darking Flag
Solenoid
WH/GRN
Conn Block Row 4
8
+5V Input
¥H
Pwr Supply J2 Pin 6
9
Polarising Key
10
+5V Input
WH
Pwr Supply J3 Pin 9
11
Photometer G1
WH/BRN
Photometer J201
Pin 9
12
Opto Collector
GY/OR
Opto Switch Term C
13
Photometer G 0
WH/BK
Photometer J201
Pin 10
14
-5V (A) Input
WHAIO
Pwr Supply J3 Pin 7
15
OV
GREY
Pwr. Supply J3 Pin 3
16
OV
GREY
Pwr Supply J3 Pin 5
17
Opto Anode
GY/BL
Opto Switch Term B
18
-5V (A) Output
WH/VIO
Photometer J201
Pin 5
19
9V Input
¥H/OR
Conn Block Row 3
20
Inlo
BLUE
Photometer J201
Pin 2
Pin
Number
21
Signal Name
. Photometer G2
Wire Colour
Destination
¥H/RD
Photometer J201
Pin 8
22
Photometer Signal
Input
RED
Photometer J201
Pin 1
23
Recorder -
OR/BK
Conn Block Row 9
24
OV (A) Output
WH/GY
Photometer J201
Pin 4
25
OV (A) Input
WH/GY
Pwr Supply J3 Pin 1
26
Photometer Signal
Screen
Screen of
Twin Screen
No Where
Photometer Board Connector J201
1
Signal Out
RED
Control Board
J100 Pin 22
2
Inlo
BLUE
Control Board
J100 Pin 20
3
+5V (A)
WHAEL
Control Board
J100 Pin 6
4
OV (A)
¥H/GY
Control Board
J100 Pin 24
5
-5V (A)
WH/VIO
Control Board
J100 Pin 18
6
1st Stage Out
Control Board
J100 Test only
7
Polarising Key
Control Board
J100
8
G2 (Unused)
WH/RD
Control Board
J100 Pin 21 •
9
G1
WH/BRN
Control Board
J100 Pin 11
G 0
¥H/BK
Control Board
J100 Pin 13
10
Pover Supply Board Connector J4
Pin
Number
Signal Name
Vire Colour
Destination
1
Input
WH/BRN
Leg 1 of L200
Regulator
2
Limiting
WH/RD
Leg 2 of L200
Regulator
3
GND
WH/OR
Leg 3 of L200
Regulator
4
Eef
WH/GRN
Leg 4 of L200
Regulator
5
Output
WH/BL
Leg 5 of L200
Regulator
6
Polarising Key
7
Fan (C)
YL/GRN
Conn Block Row 10
8
Fan (B)
YL/RED
Conn Block Row 11
9
Fan (A)
YL/BK
Conn Block Row 12
WH/OR
Conn Block Row 3
WH/OR
Grating Motor Tags
Power Supply Connector J2
1
9V
2
Polarising Key
3
9V
5 &6
4
-5V (A)
Unused
5
+5V
Unused
6
+5V
WHITE
J100 Pin 8
7
Lamp
OR/BK
Conn Block Row 1
8
Unused
9
Lamp
OR/RD
Conn Block Row 2
OV
GREY
Opto Switch
Terminals A+D
10
Pover Supply Connector J3
Signal Name
Vire Colour
Destination
Pin on J100
1
OV (A)
VH/GY
25
2
PV
GREY
Conn Block Row 7
3
OV
GREY
15
4
OV (A)
Unused
5
OV
GREY
6
OV
Unused
7
-5V (A)
WH/VIO
14
8
Polarising Key
9
+5V
WHITE
10
Pin
Number
10
16
Unused
Connector Block
Lamp
1
1
Lamp
OR/BK
Pwr Supply J2 Pin 7
Lamp
2
2
Lamp
OR/RD
Pwr Supply J2 Pin 9
3
9V Input
WH/OR
Control Board J100
Pin 19
3
9V
WH/OR
Pwr Supply J2 Pin 1
Solenoid
3
3
Solenoid
4
4
Darking Flag
Solenoid
WH/GN
Control Board J100
Pin 7
Pin
Number
Signal Name
¥ire Colour
Destination
7
OV
GREY
Pwr Supply J3 Pin 2
8
Recorder +
OR/BL
Control Board J100
Pin 4
*8
Recorder +
OR/BL
Rear Pnl Red Term
9
Recorder -
OR/BK
Control Board J100
Pin 23
*9
Recorder -
OR/BK
Rear Pnl Black Term
10
Fan (C)
YL/GRN
Pwr Supply J4 Pin 7
10
Fan
RED
To Fan
11
Fan (B)
YL/RED
Pwr Supply J4 Pin 8
11
Fan
YL
To Fan
12
Fan (A)
YL/BK
Pwr Supply J4 Pin 9
12
Fan
BK
To Fan
7
* Part of Rear Panel Assembly
6.
DISPLAY PCB, KEYBOARD PCB
6.1
General Description
6.2
Electronic Description
6.2.1
Display PCB
6.2.2
Keyboard PCB
6.3
Adjustments
6.4
Circuit Diagrams
6.5
Parts List
6.6
IC Pin Outs
6.1
General Description
The keyboard and display board are mounted on the inside of the
top cover. They are connected to the main PCB via ribbon cables.
6.2
Electronic Description
6.2.1
Display PCB
The instrument display is driven by 1103 on the main
control PCB via the two driver chips IC307 and IC308.
IC307 pulls down the numbered segment displays and IC308
drives the anodes and the sources of the individual LEDs
(such as
6.2.2
Keyboard PCB
The keyboard contains 4 key switches and the pull down
diodes necessary for operation.
6.3
Adjustments
There are no adjustments on either of these PCBs.
6.4
Circuit Magrams
4000 4563
Display PCE Circuit Diagram
4000 4565
Display PCB Component Overlay
4000 4566
Keyboard PCB Circuit Diagram
4000 4568
Keyboard PCB Component Overlay
r
d
D4
AD3
Ó
iO
S2
ZD2
M S1
X D1
1
-•
2
4
-«•
5
I
|
KEYBOARD CIRCUIT 40 00 4566
COMPONENTS SHOWN DOTTED ARE
MOUNTED ON NON-TRACK 5IDE OF BOARD
KEYBOARD ASSEMBLY 40 00 4568
6.5
Parts List
Display ]PCB
Quantity
1
Part Number
Description
4000
4564
Display PCB
4000
4563
Display Circuit
Location
6
4178 0099
5082-7750 7 Seg LED
1301-1306
3
4178 0094
5082-4670 Reet LED
D301-D3O3
1
4181 0043
Integrated Circuit
ULN2803A
1307
1
4181 0044
Integrated Circuit
UDN2981A
1308
1
4162 0068
Capacitor 1OOnF MKS 2
C301
8
4160 0299
Resistor 150R
R301-R308
Keyboard
PCB
4000
4567
Keyboard PCB
A2
4000
4566
Circuit Diagram
A4
4
4000
3607
Keytop
A2
4
4184 0046
Disc Switch
S1-S4
4
4178 4148
Diode I N 4 H 8
D1-D4
1
6.6
IC Pin Outs
ULN-2803A
DARLINGTON TRANSISTOR ARRAYS
UDN-2981A
CURRENT SOURCE DRIVERS
7.
MAINTENANCE
7.1
Introduction
7.2
Safety Notes
7.3
Special Note At>out The Monochromator
7.3.1
7.4
Fault Finding
7.4.1
7.5
7.1
Cleaning of the Optical System
Trouble Shooting Table
Mechanical Servicing
7.5.1
Removal of Top Cover
7.5.2
Removal of Main Chassis
7.5.3
Replacement of Fan
7.5-4
Lamp Output Check
7.5.5
Tungsten Lamp Replacement
7.5.6
Drive Cord Replacement
Introduction
The only user maintenance is changing the lamp and the fuse. The
LKB service engineer is responsible for all other servicing.
7.2
Safety Notes
Servicing is carried out with the cover removed so proceed with
CAUTION AS KAÏNS VOLTAGES ARE PRESENT.
7«3
Monochromator
The monochromator housing contains the grating and the stray light
filters. The filters are fixed to the arm of the grating, and by
design are in the light path when necessary.
7.3.1
Cleaning of the Optical System
The grating cannot be cleaned as this would destroy the
diffraction lines (1200/mm). The other opties should be
cleaned with a lens cloth and cleaning fluid suitable for
camera and precision optical use only.
7.4
Fault Finding
7.4.1
Trouble Shooting Table
It is too early to compile a suitable table.
See SILs for details.
7.5
Mechanical Servicing
7.5.1
•
Removal of Top Cover
The top cover is attached to the base by four screws. Undo
these screws and carefully lift the lid as the cable for
the boards mounted in the lid is attached to main chassis.
7.5.2
Removal of Main Chassis
The main chassis can be removed completely as follows:
1) Remove lid as in section 7.5.1.
2) Undo the four mounting screws.
3) Unplug the connector to lid unit.
4) Disconnect the wires from the recorder at the terminal
block.
5) Disconnect earth wire from the spade terminal on the
chassis.
7.5.3
Replacement of Fan
The fan can be replaced by first removing the lid as in
section 7-5.1. Then undo the two screws and replace with
Part Number 4000 4945.
7.5«4
Lamp Output Check
Switch on the instrument and allow to calibrate but do not
press the SET REF key.
Set the wavelength to 692nm and, without pressing the SET
REF key, read the absorbance value. This gives a measure
of the light output from the tungsten lamp. The absorbance
value obtained should be approximately O.O35A, however,
variations in output of individual lamps may result in a
range of * O.O65A of the above figure, without affecting
the performance of the instrument.
Reduced light output from the tungsten lamp will show an
increased absorbance value indicating that the lamp
requires replacement.
7.5.5
Tungsten Lamp Replacement
WARMING: THE LAMP BBCOMES VERY HOT IN USE.
COOL BEFORE CHANGING.
ENSURE IT IS
To replace the lamp proceed as follows:
a)
Switch off the instrument and disconnect the mains
input.
b)
Remove the spring cover from the lamp compartment at
the rear of the instrument as shown in Fig. 7.1.
c)
Remove the faulty lamp by sliding it upwards out of
the lamp holder. Slide the replacement lamp into the
holder. CAUTION: IF THE LAMP IS TOUCHED BY FINGERS
THEN CLEAN THE GLASS USING METHANOL.
d)
Refit the lamp compartment cover.
If, after a lamp has been replaced, the display flashes all
zeros (000) at 692nm, then proceed as follows:
a)
Remove the replacement lamp.
b)
Rotate the lamp through 180 .
c)
Replace lamp.
If after this procedure the lamp does not function
correctly then adjust photosensor PCB as in section 3«
7.5.6
Drive Cord Replacement
Remove lid as in section 7-5.1, remove chassis as in
section 7.5.2. Remove the plastic cover from the underside
of the chassis. The drive cord is then simply replaced by
hooking the new cord over the peg on the drive pulley and
attaching the other loop to the hook on the grating arm.
The Part Number for the ready-assembled drive cord is 4000
4593.
Fig. 7.1: Lamp Compartment
8.
OPERATION
8.1
8.2
8.3
8.1
Introduction
8.1.1
Key Pad
8.1.2
Display Panel
8.1.3
Sample Compartment
Instrument Operation
8.2.1
Initial Switch-On
8.2.2
Performing a Measurement
Further Operator Information
8.3-1
Introduction
8.3»2
Instrument Indications
Introduction
The three operator areas of the instrument are the key pad,
display panel and sample compartment.
8.1.1
Key Pad
The key pad comprises four individual keys, hinged along
the upper edge and ergonomically positioned such that,
during normal operation, the operator inputs progress from
left to right along the key pad. Fig. 8.1 shows the key
pad layout. The individual key functions are described
below:
a)
WAVELENGTH +/WAVELENGTH-. These keys select the
wavelength of light used for the measurement. Press
and hold either WAVELENGTH + or WAVELENGTH - to
increment or decrement the selected wavelength as
shown on the display. An automatic ramp function
increases the rate of change of wavelength with the
length of time the key is pressed until a
predetermined maximum rate is reached.
b)
MODE. Used to select the mode of instrument operation
as indicated on the display panel. This key has a
sequential operation, the order being 0-1A, 0-2A, %T,
0-1A, etc.
c)
SET REF. When pressed, this key sets the absorbance
readout to zero or the transmission readout to 100$T.
8.1.2
Display Panel
The display panel comprises two digital display units and
three indicator LEDs. Figure 8.2 shows the layout of the
display panel, the display functions are as follows:
a)
WAVELENGTH. Three digit display indicating the
selected wavelength in nanometers.
b)
MODE. Three LEDs indicating which of the three
instrument modes is selected. Only one of these
LEDs is illuminated at any one time.
0-1A. When this LED is illuminated, the measurement
display indicates the sample absorbance in the range
-.30 to .999A.
0-2A. When this LED is illuminated, the measurement
display indicates the sample absorbance in the range
-.30 to 1.99A.
$T. When this LED is illuminated, the measurement
display indicates the sample transmission, in the
range of 0.1 to 200$T.
c)
8.1.3
MEASUREMENT. Three digit display, the information
displayed being dependent on the selected mode.
Sample Compartment
The sample compartment is enclosed by a light tight cover
which is hinged along the rear edge. To gain access to the
sample compartment, lift the front of the lid. If it is
necessary to remove the lid completely, it can be sprung
off the hinge pins.
The instrument sample compartment will accommodate samples
in standard 24mm (1 ") test tubes as shown in Fig. 8.3. For
tubes greater than 100mm in length the extended sample
compartment cover should be placed over the test tube to
exclude light.
A removable small test tube/cuvette holder is supplied with
the instrument to allow samples in 12mm (1/2") test tubes
or 10mm cuvettes to be accommodated as shown in Fig 8.4.
The spring clip in the lower section of the holder, firmly
clamps the cuvette in position. A tall 10mm cuvette may
also be used with the holder. When handling cells, only
hold the cell using the ground faces.
rn
^ ^ ^ ^ W
^
•
1
WAVELENGTH
;
MODE
- • ; . ; ; > -••'!'..•.••
SET
• - ' * ' •
F i g . 8 . 1 : Key Pad
C D 0-1A
CID 0 2A
1 1 «/„f
SPECTROPHOTOMETER
WAVELENGTH
MODE
MEASUREMENT
Fig. 8.2: Display Panel
Sample Compartment
Cover
-Test Tube Cover
Small Test Tube/
Cuvette Holder
12mm Test Tube
24mm Test Tube
Fig. 8.3: Sample Compartment
Fig. 8.4: Small Test Tube/Cuvette Holder
8.2
Instrument Operation
8.2.1
Initial Switch-On
Before switching on the instrument ensure that the sample
compartment is empty with the cover closed and that the
voltage selector is set to the appropriate voltage.
To switch on the instrument, set the main ON/OFF rocker
switch located at the rear of the instrument to ON. Vhen
switched on the instrument automatically performs a series
of 3 calibration checks, for a period of approximately 90
seconds, during which the sample compartment cover must be
closed. While these calibration checks are being performed
the digital displays on the display panel are as shown in
Fig. 8.5If the calibration check fails on CAL 2 then the instrument
automatically returns to CAL 1 and recommences the
calibration process. To indicate that the calibration has
failed once, the CAL and number displays flash throughout
the subsequent recalibration. If the calibration procedure
fails totally, then the displays flash and the measurement
display holds the value of the failed calibration number.
Attempt recalibration by switching off and on again.
When the instrument has completed these checks the
operation may commence. The satisfactory conclusions of
the checks is indicated on the display panel as follows:
a)
Wavelength - changes from CAL to 36Onm.
b)
Mode - 0-1A indicated.
c)
Measurement - changes from 3 to an absorbance value
below 1A.
When this condition is achieved then the instrument is
ready for operation. If the instrument does not attain
this condition then a fault may exist.
The identification mark on the removable small test
tube/cuvette holder should be used to ensure reproducibile
location of the marked test-tube. When inserted the mark
should be nearest the front left-hand corner of the sample
compartment.
CR
Wavelength
C 3 OlA
i—i 0-2A
C=l %T
1
1
Mode
Measurement
i
No. of calibration check,
progressing from 1 to 3.
Fig. 8.5: Calibration Display
Fig. 8.6: Select Wavelength
MODE
Fig. 8.7: Select Mode
8.2.2
Performlng a Measurement
To perform a measurement in any of the three modes of
operation, proceed as follows:
8.3
a)
Select the required wavelength using the WAVELENGTH
+/- keys (Fig. 8.6).
b)
Press the MOBE key until the LED indicating the
desired operating mode is selected (Fig. 8.7).
c)
Load the reference cell or test tube into the sample
compartment and close the lid.
d)
Press the SET REF key to zero the display (Fig. 8.8).
This is either zero absorbance or 100$ transmission.
e)
Remove the reference tube and insert the sample cell
or test tube into the sample compartment then read the
absorbance or transmission value from the measurement
display.
f)
To measure further samples, repeat step e) above.
g)
If the wavelength is adjusted then return to step c)
above.
Further Operation Information
8.3.1
Introduction
The instrument provides the operator with information in
the event of action being required due to an operator error
or instrument malfunction.
n n n
u u u
MODE
MEASUREMENT
Fig. 8.8: Set Reference
f
8.3.2
c
f
Instrument Indications
The following table describes the possible indications, lists the probable reasons and then describes the
relevant operator action.
INDICATION
POSSIBLE REASON
OPERATOR ACTION
Wavelength shows only CAL 1
Grating motor failed or backstop
opto malfunction, broken drive
cord.
Check motor drive/opto electronics.
Replace drive cord.
Wavelength display flashes CAL.
Automatic calibration has failed
- the instrument re-attempts
calibration from CAL 1 .
a)
Measurement display flashes .999»
Mode 0 to 1A selected, sample
absorbance greater than 1A.
a)
b)
Measurement display flashes 1.99•
Mode 0 to 2A selected, sample
absorbance greater than 2A.
Dilute sample
Measurement display flashes 200.
Mode %T selected, sample
transmittance greater than
reference.
Range available 1.0 to 200$T.
Measurement display flashes -.30.
Mode 0 to 1A or 0 to 2A, sample
absorbance less than reference.
Range available -.30 to 1.99A.
Measurement display indicates
Wavelength value being changed.
Display returns to normal
after wavelength reaches set
value.
Instrument performing Set
Reference
Display returns to normal
after Set Ref sequence completed.
NOTE:
b)
c)
Ensure that the sample compartment
is empty.
Check the lamp.
Check that the sample compartment
lid is closed.
Select mode 0 to 2A.
Dilute sample.
When the wavelength is altered in single steps the measurement display continues to indicate value,
thus allowing maximum determinations.
C202
100PF
J201.1
SIGNAL
DECOUPLING CAPACITORS
C203 - C20G
TO BE LAYED NEAR TO
OPERATIONAL AMPLIFIERS
_ÏO1.3
+5V(A)
_201.4
SIGLOW
'01.2
TV(A)
R203
4M7
C203
1201
TLC271CP
GND
D201
PHOTO
DIODE
-vcc
R214 I1R213 n
1.21K J147K
0.1% Tl.O'A T
12
14
R216
hR2Q7
MlOK
C205
0.1UF
0.1%
R215
90.9K M
Ul.0% U
15
11
1
13
1203
MC4052
5
5
R217
100R
0. 1%
R202
4M7
sD
4
GND
PHOTOMETER PCB
4000 4574
DISPLAY P.C.B. 40 00 4563
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MOTOR
POSITION
DETECTOR
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MOTOR
CONNECTIONS
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DISPLAY PCB
KEYBOARD PCB
DECOUPLING CAPACITORS
C123 - C13S ARE ALL 0.1LF
AND TD BE MOUNTED BY IC
1111
SN74LS138
GND'
CONTROL PCB 4000 4560