Removal of the Smoke-Detection Control Unit (SDCU)

TASK 26-17-34-000-001-A
Removal of the Smoke-Detection Control Unit (SDCU)

ZONE: 122
FIN: 10WQ ** 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 1M(3 FT)
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
122	AVIONICS COMPARTMENT
811

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 31-32-00-860-005-A	Procedure to Get Access to the SYSTEM REPORT/TEST FIRE PROT Page
Smoke-Detection Control Unit

3. Job Set-up
Subtask 26-17-34-861-050-A ** ON A/C NOT FOR ALL

A. Energize the ground service network (Ref. AMM TASK 24-42-00-861-001).

Subtask 26-17-34-810-050-A ** ON A/C NOT FOR ALL

B. Trouble Shooting Data (If the Computer Has This Function)
(1) You can print the Trouble Shooting Data (TSD) as follows:

get access to the SYSTEM REPORT/TEST FIRE PROT page (Ref. AMM TASK 31-32-00-860-005).
on this page, push the line key adjacent to the SDCU indication.
on the SDCU page, push the line key adjacent to the TROUBLE SHOOTING DATA indication to get the TROUBLE SHOOTING DATA page.
print the TROUBLE SHOOTING DATA page.

Subtask 26-17-34-865-050-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
49VU	AIR COND/SDCU/CHAN1	11WQ	C06
122VU	AIR COND/SDCU/CHAN2	12WQ	T18

Subtask 26-17-34-010-050-A ** ON A/C NOT FOR ALL

D. Get Access
(1) Put the ACCESS PLATFORM 1M(3 FT) in position.
(2) Open the access door 811.

4. Procedure
Subtask 26-17-34-020-050-A ** ON A/C NOT FOR ALL

A. Remove the Smoke Detection Control Unit (SDCU)

CAUTION: BE CAREFUL WHEN YOU REMOVE THE SDCU. THERE IS NO HANDLE ON IT (OTHER LRU'S HAVE A HANDLE). DO NOT USE MECHANICAL TOOLS. MECHANICAL TOOLS CAN CAUSE DAMAGE TO THE SDCU.

(1) Loosen the knurled nut (4), and disengage it from the control unit (1).
(2) Remove the control unit (1) from the support (2).
(3) Put CAP - BLANKING on the electrical connector on the control unit (1) and on the receptacle on the rack (2).

[Rev.10 from 2021] 2026.03.31 23:44:23 UTC