Loss of the GCU1 Bus of the SDAC1

TASK 31-54-00-810-946-A
Loss of the GCU1 Bus of the SDAC1

1. Possible Causes

SDAC-1 [1WV1]
GCU-1 [1XU1]
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 24-22-34-000-001	Removal of the GCU-1(2)
AMM 24-22-34-400-001	Installation of the GCU-1(2)
AMM 31-50-00-710-001	Ground Scanning of the Central Warning System
AMM 31-55-34-000-001	Removal of the SDAC
AMM 31-55-34-400-001	Installation of the SDAC

3. Fault Confirmation
Subtask 31-54-00-710-323-A ** ON A/C NOT FOR ALL

A. Do the ground scanning of the central warning system AMM 31-50-00-710-001.

4. Fault Isolation
Subtask 31-54-00-810-194-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:

SDAC1: NO DATA FROM GCU1
(1) Replace the SDAC-1 [1WV1] AMM 31-55-34-000-001 and AMM 31-55-34-400-001.
(2) If the fault continues:

replace the GCU-1 [1XU1] AMM 24-22-34-000-001 and AMM 24-22-34-400-001.

(3) If the fault continues:

do a check and repair the wiring between the GCU1 (1XU1) and the SDAC1 (1WV1).

Subtask 31-54-00-710-324-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:30:33 UTC