TM 9-4910-663-34
Table 2-5. TROUBLESHOOTING (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
F binding posts. Set MILLIVOLT METER MILLIVOLT DROP RANGE switch S16 to X10 position.
Connect ohmmeter between REGULATOR G+ binding post and terminal 9 of PC board assembly.
Press MILLIVOLT METER MILLIVOLT DROP PRESS TO READ switch S34 momentarily, and check
for zero ohm indication on ohmmeter.
If ohmmeter indication is not zero ohm, replace MILLIVOLT METER MILLIVOLT DROP RANGE
switch S16.
Step 4.
Set MILLIVOLT METER MILLIVOLT DROP RANGE switch S16 to X1 position. Connect ohmmeter
between REGULATOR G+ binding post and terminal 8 of PC board assembly. Press MILLIVOLT
METER MILLIVOLT DROP PRESS TO READ switch S34 momentarily, and check for zero ohm
indication on ohmmeter.
If ohmmeter indication is not zero ohm, replace MILLIVOLT METER MILLIVOLT DROP RANGE
switch S16.
Step 5.
Using ohmmeter, check for 900 ohm (approximate) resistance indication between terminals 8 and 5
of PC board assembly.
If resistance indication is incorrect, check resistances of resistor R22 and potentiometer R20 on
PC board assembly with ohmmeter; replace defective part.
Step 6.
Using ohmmeter, check for 9000 ohm (approximate) indication between terminals 9 and 5 of PC
board assembly.
If resistance indication is incorrect, check resistances of resistor R23 and potentiometer R21 on
PC board assembly with ohmmeter; replace defective part.
Step 7.
Disconnect lead from positive terminal (left terminal facing rear of meter) of MILLIVOLT METER
MILLIVOLT DROP meter M4. Set ohmmeter to low range. Connect positive lead of ohmmeter to
terminal 5 of PC board assembly, and negative ohmmeter lead to terminal 10, and check for
indication between 5 and 20 ohms. Then, reverse ohmmeter leads, and check for same indication.
If correct indications are obtained for both ohmmeter
2-57
