TM 1-1520-238-T-6
9–584
9–291. LT CAUT CIRCUIT BREAKER (CB21) – DOES NOT STAY CLOSED OR 28 VDC IS NOT
9–291
PRESENT AT (A76)J1-y
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
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 LT CAUT circuit breaker (CB21) stay
closed?
YES
Go to step 4.
NO
Go to step 2.
2. On pilot center circuit breaker panel, open LT
CAUT circuit breaker (CB21). Set BATT/EXT
PWR switch to OFF. Check for short between
(A76)J1-y and ground.
Does short exist?
YES
Go to step 3.
NO
Go to paragraph 9–333 to
troubleshoot pilot
caution/warning system.
3. Detach wire at CB21-2. Check for short between
(A76)J1-y and ground.
Does short exist?
YES
Repair shorted wire.
Go to paragraph 9–263.
NO
Replace LT CAUT circuit
breaker (CB21)
(TM 1-1520-238-23).
4. Set BATT/EXT PWR switch to OFF. Check for
open between CB21-2 and (A76)J1-y.
Does open exist?
YES
Repair open wire.
Go to paragraph 9–263.
NO
Replace LT CAUT circuit
breaker (CB21)
(TM 1-1520-238-23).
END OF TASK
