TM 1-1520-238-T-6
9–396
9–155. MISSION RDR JAM AC CIRCUIT BREAKER (CB74) – DOES NOT STAY CLOSED
9–155
OR 115 VAC IS NOT PRESENT AT: P1-5, P1-6, P1-7
Tools:
Nomenclature
Part Number
Tool Kit, Electrical
SC518099CLA06
Repairer’s
Multimeter, Digital
AN/PSM-45
Personnel Required:
68X
Armament/Electrical Systems Repairer
One person to assist
References:
TM 1-1520-238-23
TM 11-1520-238-23-2
WARNING
Turn off power before detaching or
attaching wires and connectors. High
current 28 VDC or 115 VAC is present.
Failure to do so could result in death or
serious injury.
1. On pilot ELEC PWR panel, set BATT/EXT PWR
switch to EXT PWR.
Does MISSION RDR JAM AC circuit breaker
(CB74) stay closed?
YES
Go to step 4.
NO
Go to step 2.
2. Open CB74. Set BATT/EXT PWR switch to OFF.
Check for short between:
P1-5 and ground,
P1-6 and ground,
P1-7 and ground.
Does short exist?
YES
Go to step 3.
NO
Refer to TM 11-1520-238-23-2
to troubleshoot radar jamming
system.
3. Detach wire ends at CB74-A2, CB74-B2, and
CB74-C2. Check for short between:
P1-5 and ground,
P1-6 and ground,
P1-7 and ground.
Does short exist?
YES
Repair shorted wire.
Go to paragraph 9–150.
NO
Replace MISSION RDR JAM
AC circuit breaker (CB74)
(TM 1-1520-238-23).
4. Set BATT/EXT PWR switch to OFF. Check for
open between:
CB74-A1 and CB41-A1,
CB74-B1 and CB41-B1,
CB74-C1 and CB41-C1,
CB74-A2 and P1-5,
CB74-B2 and P1-6,
CB74-C2 and P1-7.
Does open exist?
YES
Repair open wire.
Go to paragraph 9–150.
NO
Replace MISSION RDR JAM
AC circuit breaker (CB74)
(TM 1-1520-238-23).
END OF TASK
