TM 1-1520-238-T-6
9–244
Change 3
9–64.
LT FORM CIRCUIT BREAKER (CB90) – DOES NOT STAY CLOSED
9–64
Tools:
Nomenclature
Part Number
Tool Kit, Electrical
SC518099CLA06
Repairer’s
Multimeter, Digital
AN/PSM-45
Personnel Required:
68X
Armament/Electrical Systems Repairer
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. Check for short between P1-24 and ground.
Does short exist?
YES
Go to paragraph 9–150 to
troubleshoot circuit protection
system (ac essential bus 1 –
pilot station).
NO
Go to step 2.
2. Check for short between (A402)J21-B12 and
ground.
Does short exist?
YES
Go to step 4.
NO
Go to step 3.
3. Check for short between:
P100-A18 and ground,
P100-A19 and ground.
Does short exist?
YES
Repair shorted wire between:
P100-A18 and P439-B14,
(A402)J21-B14 and
(A402)J1-24,
P100-A19 and P439-B12.
Go to paragraph 9–62.
NO
Replace pilot EXT LT/INTR LT
panel (TM 1-1520-238-23).
4. Detach P440, P441, P442, P431.
Check for short between (A402)J21-B12 and
ground.
Does short exist?
YES
Repair shorted wire between
(A402):
J21-B12 and TB3-19-A,
J24-A18 and TB3-19-B,
J27-A3 and TB3-19-C,
J5-A12 and TB3-19-D,
J16-A15 and TB3-19-E.
Go to paragraph 9–62.
NO
Go to step 5.
5. Check for short between P441-A18 and ground.
Does short exist?
YES
Go to step 6.
NO
Go to step 7.
