Motorola R-2001A Service Manual page 82

Table 5-6. System Troubleshooting (Cont)
Fault
No external modulation on the
CRT
Frequency Counter inoperative
DVM AC mode is inoperative
Troubleshooting Procedure
3. Check for the DPL signal at TP6 of the Audio
Synthesizer. If not present replace the Audio
Synthesizer (A6).
4. Check for the DPL signal at TP4 of the Scope
Amplifier module (A2). If not present replace
the Scope/DVM control module (A3).
5. If signal switching is okay tolhe Scope AmpI i-
fier module proceed to the scope trouble-:
shooting information.
1. Check for modulation signal at TP7 of the,
Audio Synthesizer module (A6). If not present
replace the Audio Synthesizer module.
2. Check for the modulation signal on pin 66 of
the Audio Synthesizer. If not present replace
the IEEE Interface module (A8), or check
for the presence of the modulation jumpers
on J8 for the standard unit.
3. Continue troubleshooting at step 3 of the "no ;
DPL signal on the CRT".
1. Check for presence of a 1 kHz signal at TP9 of'
the Audio Synthesizer (A6). If not present
check for the 10 MHz signal from the Fre-
quency Standard module (A13) to the RF
Synthesizer (A5). If present replace the RF
Synthesizer. If not present replace the Fre-
quency Standard module.
2. If the 1 kHz signal is present check for the
presence of the signal to be counted at pins
61 and 63 of the Processor I/O module (A7).
If not present replace the Front Panel Inter-
face Module (A12).
3. If signal is okay up to the Processor I/O
module replace the Processor I/O module.
1. Check for DVM signal at pin 22 of Processor
Interface module (A12). If not present replace
the Front Panel Interface module.
2. Check for short bursts of the DVM AC signal
at TP8 of the Scope/DVM Control module
(A3).
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