TM 1-1520-238-T-6
9447
9193. ECS AFT FAN CIRCUIT BREAKER (CB75) DOES NOT STAY CLOSED OR 115 VAC
9193
IS NOT PRESENT AT P2-A, P2-B, P2-C
Tools:
Nomenclature
Part Number
Tool Kit, Electrical
SC518099CLA06
Repairers
Multimeter, Digital
AN/PSM-45
Personnel Required:
68X
Armament/Electrical Systems Repairer
References:
TM 1-1520-238-23
TM 1-1520-238-T-8
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 ECS AFT FAN circuit breaker (CB75)
stay closed?
YES
Go to step 4.
NO
Go to step 2.
2. Set BATT/EXT PWR switch to OFF. Check for
short between:
P2-A and ground,
P2-B and ground,
P2-C and ground.
Does short exist?
YES
Go to step 3.
NO
Refer to TM 1-1520-238-T-8 to
troubleshoot environmental
control system.
3. Detach wire at CB75-A2, CB75-B2 and
CB75-C2. Check for short between:
P2-A and ground,
P2-B and ground,
P2-C and ground.
Does short exist?
YES
Repair shorted wire.
Go to paragraph 9189.
NO
Replace ECS AFT FAN circuit
breaker (CB75)
(TM 1-1520-238-23).
4. Open CB75. Set BATT/EXT PWR switch to OFF.
Check for open between:
CB78-A1 and CB75-A1,
CB78-B1 and CB75-B1,
CB78-C1 and CB75-C1,
P2-A and CB75-A2,
P2-B and CB75-B2,
P2-C and CB75-C2.
Does open exist?
YES
Repair open wire.
Go to paragraph 9189.
NO
Replace ECS AFT FAN circuit
breaker (CB75)
(TM 1-1520-238-23).
END OF TASK
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