Installation of the Audio Mixing Box

TASK 31-53-33-400-001-A
Installation of the Audio Mixing Box

ZONE: 120
FIN: 15WW ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
120	AVIONICS COMPARTMENT
811

C. Referenced Information

REFERENCE	DESIGNATION
TASK 23-71-00-710-001-A	Operational Check of CVR and CVR-Channel Recording
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 34-41-00-740-002-A	BITE Test of the Weather Radar
TASK 52-41-00-410-002-A	Close the Avionics Compartment Doors after Access
Audio Mixing Box (15WW)

3. Job Set-up
Subtask 31-53-33-860-050-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Make sure that the ground servise network is energized (Ref. AMM TASK 24-42-00-861-001).
(2) Make sure that the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE is in position at the access door 811.
(3) Make sure that the access door 811 is open (Ref. AMM TASK 52-41-00-410-002).

Subtask 31-53-33-875-051-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	AUDIO MIXING	14WW	K03

4. Procedure
Subtask 31-53-33-420-050-A ** ON A/C NOT FOR ALL

A. Installation of the Audio Mixing Box.
(1) Clean the component interfaces and the adjacent area.
(2) Install the audio mixing box (2).
(3) Install the four washers (4) and screws (3).
(4) Tighten the four screws (3).
(5) Remove the CAP-BLANKING from each electrical connector and receptacle.
(6) Make sure that all the electrical connections are clean and in the correct condition.
(7) Connect the electrical connector (1)

Subtask 31-53-33-875-052-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	AUDIO MIXING	14WW	K03

Subtask 31-53-33-860-051-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(2) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 31-53-33-710-050-A ** ON A/C NOT FOR ALL

D. Test
(1) Do the operational test of the CVR and the CVR channel recording (Ref. AMM TASK 23-71-00-710-001).
(2) Do the BITE test of the weather radar (Ref. AMM TASK 34-41-00-740-002).

5. Close-up
Subtask 31-53-33-410-050-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the access door 811 (Ref. AMM TASK 52-41-00-410-002).
(3) Remove the access platform(s).

Subtask 31-53-33-862-050-A ** ON A/C NOT FOR ALL

B. De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.01 00:37:27 UTC