TM 1-1520-238-T-4
4–100
4–20.
ENG START CIRCUIT BREAKER – DOES NOT STAY CLOSED (WITH ENG START NO 1
4–20
SWITCH IN START POSITION) (cont)
9. Detach P439. Check for short between P439–A2
and ground.
Does short exist?
YES
Go to step 10.
NO
Replace engine starter regulator
valve (TM 1-1520-238-23).
10. Detach P21. Check for short between P21–25
and ground.
Does short exist?
YES
(ABY) Repair shorted wire.
Go to paragraph 4–12.
(ABZ) Replace wire harness
(TM 1-1520-238-23).
NO
Repair shorted wire between
P439–A2 and J21–25.
Go to paragraph 4–12.
11. Detach P1370. Check for short between
P977–B3 and ground.
Does short exist?
YES
Repair shorted wire between
P977–B3 and P64–D.
Go to paragraph 4–12.
NO
Replace air turbine speed
starter switch
(TM 1-1520-238-23).
12. Check for short between P438–A2 and ground.
Does short exist?
YES
Go to step 13.
NO
Go to step 15.
13. Detach P40. Check for short between P438–A2
and ground.
Does short exist?
YES
Go to step 14.
NO
Replace engine 2 starter
regulator valve
(TM 1-1520-238-23).
14. Detach P22. Check for short between P40–4
and ground.
Does short exist?
YES
(ABY) Repair shorted wire.
(ABZ) Replace wire harness
(TM 1-1520-238-23).
Go to paragraph 4–12.
NO
Repair shorted wire between
J22–25 and P438–A2.
Go to paragraph 4–12.
15. Check for short between P439–A15 and ground.
Does short exist?
YES
Go to step 16.
NO
Go to step 17.
16. Detach P175. Check for short between
P439–A15 and ground.
Does short exist?
YES
Repair shorted wire between
P439–A15 and P175–11.
Go to paragraph 4–12.
NO
Replace pilot EMERG PWR
CHK OVSP TEST panel
(TM 1-1520-238-23).
17. Check for short between P439–A11 and ground.
Does short exist?
YES
Go to step 18.
NO
Go to step 19.
18. Detach P978. Check for short between
P439–A11 and ground.
Does short exist?
YES
Repair shorted wire between
P439–A11 and P978–A13.
Go to paragraph 4–12.
NO
Replace start mode relay panel
(TM 1-1520-238-23).
