Motorola R-2002A Manual page 79

Table 5-6. System Troubleshooting (Cont)
Test Paragraph
Fault
Troubleshooting Procedure
NOTE
The DVM AC signal from the external input is
multiplexed with the other signals to be mea-
sured. Thus only short bursts of the input signal
wi II be observed at TP8.
If signal is not present at TP8 replace the
Scope/DVM Control module.
3. If the signal is okay to TP8 of A3, replace the
Processor 1/0 module (A7).
5-137 DVM DC mode is inoperative 1.
Check for the DC input level attenuated by
factors of 1 0 to less than 1 volt at pin 22 of the
Front Panel Interface module (A12). If not
present or if greater than 1 volt, replace the
Front Panel Interface module.
2. If the signal is okay from A 12, switch to the AC
mode and apply an AC signal to the DVM in-
put. Proceed from step 2 under DVM AC
mode inoperative.
5-138 No horizontal sweep
1. Check for a voltage level between -2.0 VDC
and +2.0 VDC at TP4 of the Scope Amplifier
module (A2). If the voltage cannot be brought
within range with either the vertical range
attenuator or the vertical position control
replace the Front Panel Interface module
(A12).
2.
If the voltage at TP4 is okay replace the Scope
Amplifier module (A2).
5-138
No vertical display
1. Check for the input signal at TP4 of the Scope
Amplifier module (A2). If not present replace
the Front Panel Interface module (A12).
2. If signal is okay at TP4 replace the Scope
Amplifier module.
5-138 No vertical sync
1. Check for the presence of sync pulses at pin
12 of the Scope/DVM Control module (A3)
and for a nominal zero volt sync present level
at pin 76. If either signal is not present replace
the Scope/DVM Control module.
5-40