Failure of the A629 BUS from the F/O ND DU to the DMC3

TASK 31-63-81-810-975-A
Failure of the A629 BUS from the F/O ND DU to the DMC3

1. Possible Causes

wiring
ND-F/O [3WT2]
DMC-3 [1WT3]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 31-63-81-810-969-A	Failure of the A629 BUS from the F/O ND DU to the DMC2
AMM 31-60-00-720-002	Operational Test of the DMC/DU data bus
ASM 316105
AMM 31-63-22-000-001	Removal of the Display Unit
AMM 31-63-22-400-001	Installation of the Display Unit
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC

3. Fault Confirmation
Subtask 31-63-81-720-105-A ** ON A/C NOT FOR ALL

A. Test
(1) Make sure that the DMC2 is correctly installed AMM 31-63-34-400-001.
(2) Do the operational test of the DMC/DU Data Bus AMM 31-60-00-720-002.

4. Fault Isolation
Subtask 31-63-81-810-260-A ** ON A/C NOT FOR ALL

A. If the test gives:
(1) The maintenance message DU ND FO(3WT2)/DMC2(1WT2):

Do the relative fault isolation procedure (Ref. TSM TASK 31-63-81-810-969).

(2) The maintenance message DU ND FO(3WT2)/DMC3(1WT3):

Check the wiring between the DMC2 and the DMC3 ASM 316105.

(a) If the wiring is correct:

Replace the ND-F/O [3WT2] AMM 31-63-22-000-001 and AMM 31-63-22-400-001.

(b) If the fault continues:

Replace the DMC-3 [1WT3] AMM 31-63-34-000-001 and AMM 31-63-34-400-001.

Subtask 31-63-81-720-106-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:31:11 UTC