SDCU Channel 2 Fault

TASK 26-17-00-810-814-A
SDCU Channel 2 Fault

1. Possible Causes

SDCU [10WQ]
aircraft wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 261702
AMM 26-17-34-000-001	Removal of the Smoke-Detection Control Unit (SDCU)
AMM 26-17-34-400-001	Installation of the Smoke-Detection Control Unit (SDCU)
AMM 31-32-00-860-005	Procedure to Get Access to the SYSTEM REPORT/TEST FIRE PROT Page

3. Fault Confirmation
Subtask 26-17-00-865-057-A ** ON A/C NOT FOR ALL

A. Table of the circuit breakers used in this procedure:

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 26-17-00-710-074-A ** ON A/C NOT FOR ALL

B. Test
(1) Open the circuit breakers 11WQ and 12WQ.
(a) After 60 seconds, close the circuit breakers 11WQ and 12WQ.
(b) After one more minute, start the subsequent test.
(2) Get access to the MCDU/SDCU menu page AMM 31-32-00-860-005.
(a) Push the line key adjacent to the <ON GROUND FAULTS indication.

4. Fault Isolation
Subtask 26-17-00-810-096-A ** ON A/C NOT FOR ALL

A. If the MCDU gives the maintenance message NO FAILURE, no other maintenance action is necessary.

Subtask 26-17-00-810-097-A ** ON A/C NOT FOR ALL

B. If the MCDU gives the maintenance message SDCU CHANNEL 2 (10WQ)

replace the SDCU [10WQ] AMM 26-17-34-000-001 AMM 26-17-34-400-001.

(1) If the fault continues:

do a check and repair the aircraft wiring from the circuit breaker 12WQ to the SDCU [10WQ] AC/4 ASM 261702.

5. Close-up
Subtask 26-17-00-710-075-A ** ON A/C NOT FOR ALL

A. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:27:21 UTC