TM 1-1520-238-T-7
Change 5
11–418.1
11–120. AUDIO TONE – IS NOT HEARD IN BOTH CREW STATIONS (cont)
11–120
4. Open ENG WARN (A76)CB52 circuit breaker.
Detach J993 from (A641)P1.
Check for continuity between P993–F and
P993–E.
Does continuity exist?
YES
Replace pilot RESET switch
(A641) (TM 1-1520-238-23).
NO
Go to step 5.
5. Detach J994 from (A641)P1.
Check for continuity between P994–F and
P994–E.
Does continuity exist?
YES
Replace CPG RESET switch
(A641) (TM 1-1520-238-23).
NO
Go to step 6.
6. Attach:
P1077 to (A329)J1,
P491to (A323)J6.
Detach P429 from (A402)J23.
Check for short between:
J993–E and ground,
J994–E and ground.
Does short exist?
YES
Repair shorted wire between.
J993–E and P429–B8,
J994–E and P429–B9.
Go to paragraph 11–88.
NO
Go to step 7.
7. Detach P431 from (A402)J27.
Check for short between (A402)J27–A20 and
ground.
Does short exist?
YES
Repair shorted wire between
(A402):
J27–A20 and TB2–26/27–G,
TB2–26/27–A and
TB2–26/27–B,
TB2–26/27–P and J23–B8,
TB2–26/27–C and J23–B9.
NO
Go to step 8.
8. Detach P491from (A323)J6.
Check for short between P431–A20 and ground.
Does short exist?
YES
Repair shorted wire between
P431–A20 and P491–A18.
Go to paragraph 11–88.
NO
Go to step 9.
9. Check for short between (A323)J6–A18 and
ground.
Does short exist?
YES
Repair shorted wire between
(A323) J6–A18 and J6–A19.
Go to paragraph 11–88.
NO
Go to step 10.
10. Check for short between P491–A19 and ground.
Does short exist?
YES
Go to step 11.
NO
Go to step 12.
11. Detach P987 from (A637–J3).
Check for short between P491–A19 and ground.
Does short exist?
YES
Repair shorted wire between
P491–A19 and P987–E.
Go to paragraph 11–88.
NO
Replace STAB CONT UNIT 1
(A637) (TM 1-1520-238-23).
12. Detach P1077 from (A329)J1.
Check for short between P491–A20 and ground.
Does short exist?
YES
Repair shorted wire between
P491–A20 and P1077–H.
Go to paragraph 11–88.
NO
Go to step 13.
