Removal of the DC Service Bus Normal Supply Contactor

TASK 24-61-55-000-001-A
Removal of the DC Service Bus Normal Supply Contactor

WARNING: MAKE SURE THAT NO AC OR DC POWER IS CONNECTED TO THE AIRCRAFT ELECTRICAL CIRCUITS. THERE IS A RISK OF ELECTROCUTION IF THE AC OR DC POWER STAYS CONNECTED.

ZONE: 125
FIN: 8PN

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 1M (3 FT)-ADJUSTABLE
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
125	LATERAL AVIONIC COMPARTMENT
121AL

C. Referenced Information

REFERENCE	DESIGNATION
TASK 25-11-41-000-001-A	Removal of the Third Occupant Seat
Contactor ** ON A/C NOT FOR ALL
Contactor ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 24-61-55-010-050-A

A. Get Access
(1) Remove the Third Occupant seat (Ref. AMM TASK 25-11-41-000-001).
(2) Remove the front panel on the bottom right side of the panel 120VU.
(3) Put the ACCESS PLATFORM 1M (3 FT)-ADJUSTABLE in position at the access door 121AL.
(4) Open the access door 121AL.

Subtask 24-61-55-860-050-A

B. Safety Precautions
(1) Make sure that the external power connector is not connected to the aircraft EXT PWR receptacle.
(2) Put WARNING NOTICE(S) in position on the access door 121AL to tell persons not to connect the external power connector to the aircraft EXT PWR receptacle.
(3) In the cockpit, on the ELEC panel 35VU, make sure that these pushbutton switches are released:

BAT 1, BAT 2,
APU GEN,
GEN 1, GEN 2,
EXT PWR.

(4) In the cockpit, put WARNING NOTICE(S) in position to tell the persons not to operate the pushbutton switches on these overhead panels:

21VU (EMER ELEC PWR section),
25VU (APU section),
35VU (ELEC).

(5) In the cockpit, on the APU section of the overhead panel 25VU, put a WARNING NOTICE(S) to tell persons not to start the APU.

4. Procedure
Subtask 24-61-55-020-050-A

A. Removal of the Contactor

CAUTION: REMOVE THE CONTACTOR ONLY AND NOT THE BASE OR THE MODULE WHERE THE WIRES ARE CONNECTED.

(1) Disconnect the electrical connector (4).
(2) Put a blanking caps on the disconnected electrical connector (4) and the electrical receptacle.
(3) Loosen the captive screws (2).

NOTE: Do not remove the captive screws (2) and the spring washers from the contactor (3).

(4) Remove the contactor (3).

[Rev.10 from 2021] 2026.04.01 05:53:51 UTC