TM 1-1520-238-T-6
9–405
9–164. LT FORM CIRCUIT BREAKER (CB90) – DOES NOT STAY CLOSED OR 115 VAC
9–164
IS NOT PRESENT AT P1-24
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 FORM circuit breaker (CB90) stay
closed?
YES
Go to step 4.
NO
Go to step 2.
2. Open CB90. Set BATT/EXT PWR switch to OFF.
Check for short between P1-24 and ground.
Does short exist?
YES
Go to step 3.
NO
Go to paragraph 9–62 to
troubleshoot formation lights.
3. Detach wire at CB90-2. Check for short between
P1-24 and ground.
Does short exist?
YES
Repair shorted wire between
CB90-2 and P1-24.
Go to paragraph 9–150.
NO
Replace LT FORM circuit
breaker (CB90)
(TM 1-1520-238-23).
4. Set BATT/EXT PWR switch to OFF. Check for
open between:
CB90-1 and CB40-1,
CB90-2 and P1-24.
Does open exist?
YES
Repair open wire.
Go to paragraph 9–150.
NO
Replace LT FORM circuit
breaker (CB90)
(TM 1-1520-238-23).
END OF TASK
