TM 1-1520-238-T-4
Change 1
4–137
4–53.
EMERG PWR INDICATOR – IS NOT LIGHTED WITH CKT B SWITCH SET TO ENG 1
4–53
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-T-6
TM 1-1520-238-23
TM 55-2840-248-23
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 28 VDC at P175–11.
Is voltage present?
YES
Go to step 3.
NO
Go to step 2.
2. Check for 28 VDC at P439–A14.
Is voltage present?
YES
Repair open between:
P439–A15 and P175–11.
(A402):
J21–A14 and TB1–8–A,
J21–A15 and TB1–8–B.
Go to paragraph 4–12.
NO
Go to step 4.
3. Set and hold CKT B switch in ENG 1, check for
open between (A78):
J1–3 and XK1–X2,
J1–1 and XK1–X1.
Does open exist?
YES
Go to step 5.
NO
Go to step 7.
4. Check for open between P439–A14 and
P463–c.
Does open exist?
YES
Repair open wire.
Go to paragraph 4–12.
NO
Refer to TM 1-1520-238-T-6 to
troubleshoot circuit protection
system (dc emergency bus –
pilot station)
5. Check for open between (A78):
J1–3 and S1–6,
S1–5 and XK1–X2,
J1–1 and S1–3,
S1–2 and XK1–X1.
Does open exist?
YES
Repair open wire.
Go to paragraph 4–12.
NO
Go to step 6.
6. Check for open between (A78):
K1–X1 and K1–X2,
K1–2 and K1–4.
Does open exist?
YES
Replace power check light relay
(A78)K1 (TM 1-1520-238-23).
NO
Replace CKT B switch (A78)S1
(TM 1-1520-238-23).
