TM 1-1520-238-T-5
7–139
7–47.
FUEL BST CIRCUIT BREAKER – DOES NOT STAY CLOSED
7–47
Tools:
Nomenclature
Part Number
Tool Kit, Electrical
SC518099CLA06
Repairer’s
Multimeter, Digital
AN/PSM-45
Extractor, Relay
CTJ-RO6
Personnel Required:
68X
Armament/Electrical Systems Repairer
References:
TM 1-1520-238-T-6
TM 1-1520-238-T-7
TM 1-1520-238-T-8
TM 1-1520-238-23
Equipment Conditions:
Ref
Condition
TM 1-1520-238-23
Access provisions –
R200 panel removed
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. Open FUEL BST circuit breaker. Check for short
between P1–48 and ground.
Does short exist?
YES
Refer to TM 1-1520-238-T-6 to
troubleshoot circuit protection
system (dc emergency bus –
pilot station).
NO
Go to step 2.
2. Check for short between (A402)J1–48 and
ground.
Does short exist?
YES
Go to step 3.
NO
Refer to TM 1-1520-238-T-7 to
troubleshoot fuel
crossfeed/boost system.
3. Detach wire end from (A402)TB2–6–E. Check
for short between (A402)J1–48 and ground.
Does short exist?
YES
Go to step 4.
NO
Refer to TM 1-1520-238-T-8 to
troubleshoot APU fire detection
system.
4. Detach P217. Check for short between P217–1
and ground.
Does short exist?
YES
Go to step 5.
NO
Replace SDC inlet throttle valve
(TM 1-1520-238-23).
5. Check for short between (A402)XK2–1/2–A3
and ground.
Does short exist?
YES
Repair shorted wire between:
P217–1 and P442–B3.
(A402):
XK2–1/2–A3 and J5–B3.
Go to paragraph 7–45.
NO
Go to step 6.
