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Table 5-6.
System Troubleshooting (Coni)
Test Paragraph
Fault
Troubleshooting Procedure
5-144
No spectrum analyzer sweep
1. Check pin 6 of the RF Synthesizer module
(AS) for a 50 Hz square wave. If not present
replace the RF Synthesizer module.
2. If 50 Hz signal is present replace the Scope/
DVM Control module (A3).
5-144
Spectrum display is in error
1 . Replace the Receiver module (A4).
5-145
No duplex output
1. Replace the RF Input module (A 11 ).
Table 5-7.
Test Point Identification
All test points are located near the top edge of the card and counted from left to right when facing the
component side of the card.
Module
Test Point No.
Signal Name
A1
Low Voltage
Power Supply
A1A1
101
Pulse Width Mod Out
102
Pulse Width Mod Dr
103
HV Source Voltage
A1A2
201
Ground
202
+5V FB
203
-5V
204
+12V
205
-12V
206
+33V
207
+110V
208
-110V
A1A3
Control Board
301
+8V
302
PWM Dr
303
Error Voltage
304
H.V. Bias Supply Voltage
305
Sawtooth Voltage
306
Chopper DR A
307
Chopper DR B
5-44
Table 5-7.
Test Point Identification
Module
Test Point No.
Signal Name
A1A4
Relay Assembly
401
Batt Chg
402
Freqency Std Sup Voltage
403
Relay +12V
404
De Bus
A2
1
lnt Horiz Input
Scope Amplifier
2
Horizontal Deflection Plate
3
Horizontal Deflection Plate
4
Vertical Drive
5
Focus TV
6
Vertical Deflection Plate
7
Vertical Deflection Plate
8
CRT Z-Axis
9
Intensity TV
10
Time Base Output
A3
1
Vertical Character Sync
Scope/ DVM
2
Negative Peak Detector Output
Control
3
Gen Carrier Plus AM Level
4
Positive Peak Detector Output
5
Demodulated Calibrated Audio
6
Not Used
7
Ground
8
Multiplexed A/D Signal
9
Character Generator Reset
10
Ground
11
-8 VDC
12
+8 VDC
A6
1
Synth/DPL Audio
Audio Synthesizer
2
DPL Clock
3
Unfiltered DPL
5-45
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