Removal of the Power Supply Unit (PSU)

TASK 33-21-31-000-801-A
Removal of the Power Supply Unit (PSU)

ZONE: 240
FIN: 572LG ** 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	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	STEPLADDER 1.0 M (3.3 FT)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
240	MID PASSENGER COMPARTMENT
FOR [572LG] (POWER SUPPLY UNIT)
241EC

C. Referenced Information

REFERENCE	DESIGNATION
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)
Power Supply Unit (PSU)
FOR [572LG] (POWER SUPPLY UNIT)
TASK 25-23-41-000-001-A	Removal of the Ceiling Panels

3. Job Set-up
Subtask 33-21-31-861-050-A ** ON A/C NOT FOR ALL

A. Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 33-21-31-010-050-A ** ON A/C NOT FOR ALL

B. Get Access
(1) Put a STEPLADDER 1.0 M (3.3 FT) in position.
(2) Remove the ceiling panel:
(a) FOR [572LG] (POWER SUPPLY UNIT)
Remove 241EC (Ref. AMM TASK 25-23-41-000-001).

Subtask 33-21-31-865-050-A ** ON A/C NOT FOR ALL

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
2000VU	LIGHT-HATRACK-STRIP	312LG	J05

4. Procedure
Subtask 33-21-31-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the PSU

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTORS ARE CLEAN BEFORE YOU DISCONNECT OR CONNECT THEM. CONTAMINATION ON THE ELECTRICAL CONNECTORS CAN CAUSE DAMAGE TO EQUIPMENT.

CAUTION: MAKE MATCH MARKS ON ALL THE ELECTRICAL WIRES BEFORE YOU DISCONNECT THEM. INCORRECT CONNECTION OF WIRES WILL CAUSE DAMAGE TO EQUIPMENT.

(1) Disconnect the electrical connectors (4) and (5) from the PSU (1).
(2) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTOR(S) IS(ARE) DISCONNECTED BEFORE YOU DISCONNECT THE BONDING STRAP(S).

(3) Remove the nut (7) and the bonding strap (6) from the PSU (1).
(4) Remove the screws (3) and the washers (2).
(5) Remove the PSU (1) from its support.

[Rev.10 from 2021] 2026.04.01 00:53:28 UTC