Permanent noise from the cockpit loudspeaker(s)

TASK 31-53-00-810-969-A
Permanent noise from the cockpit loudspeaker(s)

1. Possible Causes

FWC-1 [1WW1]
FWC-2 [1WW2]
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 235106
AMM 23-51-34-000-001	Removal of the Audio Management Unit (AMU) (1RN)
AMM 23-51-34-400-001	Installation of the Audio Management Unit (AMU) (1RN)
AMM 31-53-34-000-001	Removal of the Flight Warning Computer (FWC)
AMM 31-53-34-400-001	Installation of the Flight Warning Computer (FWC)

3. Fault Confirmation
Subtask 31-53-00-700-055-A

A. Test
(1) Not applicable, the fault is evident.

4. Fault Isolation
Subtask 31-53-00-810-219-A

A. If there is confirmation of the fault:
(1) Replace the FWC for which the fault occurred:

FWC-1 [1WW1] or FWC-2 [1WW2] AMM 31-53-34-000-001 and AMM 31-53-34-400-001.

(2) Do the test(s) given in the Para. Fault Confirmation.

Subtask 31-53-00-810-220-A

B. If the fault continues:
Do a check and repair the wiring of the FWC for which the fault occurred.
(1) For the FWC1
(a) Remove the FWC1 AMM 31-53-34-000-001.
(b) Remove the AMU AMM 23-51-34-000-001.
(c) Do a check and repair the wiring from:

The FWC1 pin AA/7G to the AMU pin AB/12H
The AMU pin AB/13H to the ground terminal block
ASM 235106.

(d) Install the AMU AMM 23-51-34-400-001.
(e) Install the FWC1 AMM 31-53-34-400-001.
(f) Do the test(s) given in the Para. Fault Confirmation.
(2) For the FWC2
(a) Remove the FWC2 AMM 31-53-34-000-001.
(b) Remove the AMU AMM 23-51-34-000-001.
(c) Do a check and repair the wiring from:

The FWC2 pin AA/7G to the AMU pin AB/12H
The AMU pin AB/13H to the ground terminal block
ASM 235106.

(d) Install the AMU AMM 23-51-34-400-001.
(e) Install the FWC2 AMM 31-53-34-400-001.
(f) Do the test(s) given in the Para. Fault Confirmation.

5. Close-up
Subtask 31-53-00-942-050-A

A. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.

[Rev.8 from Aug 2018] 2026.04.04 04:38:57 UTC