Removal of the Isolation Units

TASK 23-44-42-000-001-A
Removal of the Isolation Units

ZONE: 200
FIN: 4RJ1
FIN: 4RJ2
FIN: 4RJ3
FIN: 4RJ4
FIN: 4RJ5

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	SAFETY CLIP - CIRCUIT BREAKER
FOR [4RJ1] (ISOLATION UNIT)
No specific	1	ACCESS PLATFORM 2M (6 FT)
FOR [4RJ2] (ISOLATION UNIT)
No specific	1	ACCESS PLATFORM 2M (6 FT)
FOR [4RJ3] (ISOLATION UNIT)
No specific	1	ACCESS PLATFORM 2M (6 FT)
FOR [4RJ4] (ISOLATION UNIT)
No specific	1	ACCESS PLATFORM 2M (6 FT)
FOR [4RJ5] (ISOLATION UNIT)
No specific	1	ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
200	UPPER HALF FUSELAGE
FOR [4RJ1] (ISOLATION UNIT)
822
FOR [4RJ2] (ISOLATION UNIT)
824
FOR [4RJ3] (ISOLATION UNIT)
131CC
FOR [4RJ4] (ISOLATION UNIT)
132PW
FOR [4RJ5] (ISOLATION UNIT)
312AR

C. Referenced Information

REFERENCE	DESIGNATION
ESPM 204825
Isolation Unit ** ON A/C NOT FOR ALL
Isolation Unit ** ON A/C NOT FOR ALL
Isolation Unit ** ON A/C NOT FOR ALL
Isolation Unit ** ON A/C NOT FOR ALL
Isolation Unit ** ON A/C NOT FOR ALL
FOR [4RJ1] (ISOLATION UNIT)
TASK 52-41-00-010-002-A	Open the Avionics Compartment Doors for Access
FOR [4RJ2] (ISOLATION UNIT)
TASK 52-41-00-010-002-A	Open the Avionics Compartment Doors for Access
FOR [4RJ3] (ISOLATION UNIT)
TASK 25-54-12-000-002-A	Removal of the Ceiling Panels in the Forward Cargo Compartment
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
FOR [4RJ4] (ISOLATION UNIT)
TASK 25-54-12-000-001-A	Removal of the Forward Cargo-Compartment Partition
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump

3. Job Set-up
Subtask 23-44-42-010-050-A ** ON A/C NOT FOR ALL

A. Get Access
(1) FOR [4RJ1] (ISOLATION UNIT)
(a) Put the ACCESS PLATFORM 2M (6 FT) in position below access door 822.
(b) Open access door 822 to get access to the avionics compartment (Ref. AMM TASK 52-41-00-010-002).
(2) FOR [4RJ2] (ISOLATION UNIT)
(a) Put the ACCESS PLATFORM 2M (6 FT) in position below access door 824.
(b) Open access door 824 to get access to the avionics compartment (Ref. AMM TASK 52-41-00-010-002).
(3) FOR [4RJ3] (ISOLATION UNIT)
(a) Open the forward cargo-compartment door and safety it with the actuator safety locks (Ref. AMM TASK 52-30-00-860-001).
(b) Put the ACCESS PLATFORM 2M (6 FT) in position below the opened forward cargo-compartment door.
(c) Remove ceiling panel 131CC of the forward cargo compartment (Ref. AMM TASK 25-54-12-000-002).
(4) FOR [4RJ4] (ISOLATION UNIT)
(a) Open the forward cargo-compartment door and safety it with the actuator safety locks (Ref. AMM TASK 52-30-00-860-001).
(b) Put the ACCESS PLATFORM 2M (6 FT) in position below the opened forward cargo-compartment door.
(c) Remove partition 132PW at FR34 of the forward cargo compartment (Ref. AMM TASK 25-54-12-000-001).
(5) FOR [4RJ5] (ISOLATION UNIT)
(a) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below access door 312AR.
(b) Open access door 312AR.

Subtask 23-44-42-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	COM/CIDS/DIR ESS/2	157RH	G02
** ON A/C NOT FOR ALL
49VU	COM/CIDS/DIR ESS/1	150RH	G01
** ON A/C NOT FOR ALL
49VU	COM DIR ESS/2	157RH	G02
** ON A/C NOT FOR ALL
49VU	COM NAV/CIDS/DIR2 ESS	157RH	G02
49VU	COM NAV/CIDS/DIR1 ESS	150RH	G01
** ON A/C NOT FOR ALL
121VU	COM NAV/CIDS/DIR NORM/2	156RH	M06
121VU	COM NAV/CIDS/DIR NORM/1	151RH	M05
** ON A/C NOT FOR ALL
121VU	COM NAV/CIDS/DIR NORM/2	156RH	M07
121VU	COM NAV/CIDS/DIR NORM/1	151RH	M06
** ON A/C NOT FOR ALL
121VU	COM NAV/CIDS/DIR2 NORM	156RH	M06
121VU	COM NAV/CIDS/DIR1 NORM	151RH	M05

4. Procedure
Subtask 23-44-42-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Isolation Units
(1) Make match marks on the components that you disconnect/remove to record their connections/positions. This is important for the subsequent installation procedure.
(2) Disconnect the wires of the cable harness (1) from the connector of the PC-board (2) and safety them ESPM 204825.

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

(3) Cut and remove the lockwire from the clamp screw (7).
(4) Loosen the clamp screw (7) and remove the end clamp (8) from the mounting rail (3).
(5) Remove the PC-board bracket (6) together with the PC-board (2) from the mounting rail (3).
(6) If necessary, remove the nuts (4) and the washers (5) to disassemble the PC-board (2) from the PC-board bracket (6).

[Rev.10 from 2021] 2026.04.02 06:50:42 UTC