TM- 9-4910-663-34
Table 2-5. TROUBLESHOOTING (Continued)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
4. RELAY CONTACT CLOSURE CIRCUIT/DC CONTROL POWER
a. WITH JUMPER CONNECTED BETWEEN RELAY CONTACTS INPUT BINDING POSTS, CONTACT CLOSURE
INDICATOR DS7 FAILS TO LIGHT.
Step 1. Check to make sure that circuit breaker switch CB1, CIRCUIT BREAKERS CB2 DRIVE CONTROL
circuit breaker, and CIRCUIT BREAKERS CB5 RELAY CONTROL circuit breaker are all set to ON
position.
Set circuit breakers to ON position.
Step 2. Set circuit breaker switch CB1 to OFF position. Remove lamp from CONTACT CLOSURE indicator
DS7, and check lamp filament for continuity with ohmmeter.
Replace lamp if open indication is obtained.
Step 3. With circuit breaker switch CB1 set to OFF position, check resistance across terminals of resistor R5
with ohmmeter.
Replace resistor RS if resistance indication is not within 150 ±15 ohms.
Step 4. Set circuit breaker switch CB1 to ON position. Using DC voltmeter, check for 26 to 30 volt DC
indication between RELAY CONTACTS INPUT binding posts.
If DC voltage is not as specified, set circuit breaker switch CB1 to OFF position and proceed to step
5.
Step 5. With circuit breaker switch CB1 set to OFF position, disconnect lead from one terminal of CIRCUIT
BREAKERS CB5 RELAY CONTROL circuit breaker. Using ohmmeter, check for continuity across
terminals of circuit breaker CB5 with circuit breaker set to ON position.
Replace circuit breaker CB5 if open indication is obtained.
Step 6. Reconnect lead disconnected in step 5. Disconnect lead from ± terminal of rectifier assembly CR1
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