Loss of the ARINC 429 Link between the FWC2 and the DMC2

TASK 31-63-00-810-962-A
Loss of the ARINC 429 Link between the FWC2 and the DMC2

1. Possible Causes

DMC-2 [1WT2]
FWC-2 [1WW2]
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 315205
AMM 31-53-34-000-001	Removal of the Flight Warning Computer (FWC)
AMM 31-53-34-400-001	Installation of the Flight Warning Computer (FWC)
AMM 31-60-00-740-002	Perform Electronic Instrument System (EIS) Input Test
AMM 31-60-00-740-007	GROUND SCANNING Test of the DMC
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC

3. Fault Confirmation
Subtask 31-63-00-865-191-A

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	EIS/FWC2/SPLY	2WW	Q07

Subtask 31-63-00-740-334-A ** ON A/C NOT FOR ALL

B. Test
Do the EIS input test (system 2) AMM 31-60-00-740-002.

Subtask 31-63-00-740-334-B ** ON A/C NOT FOR ALL

B. Test
Do the Ground Scanning Test of the DMC AMM 31-60-00-740-007.

4. Fault Isolation
Subtask 31-63-00-810-210-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:
DMC2: NO FWC2 DATA

replace the DMC-2 [1WT2] AMM 31-63-34-000-001 and AMM 31-63-34-400-001.

(1) If the fault continues:

replace the FWC-2 [1WW2] AMM 31-53-34-000-001 and AMM 31-53-34-400-001.

(a) If the fault continues:

do a check and repair the wiring from DMC2 (1WT2) pins AA/10J, 10K to the FWC2 (1WW2) ASM 315205.

Subtask 31-63-00-810-210-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:
FWC2(1WW2) BUSX DATA/DMC2(1WT2)

replace the DMC-2 [1WT2] AMM 31-63-34-000-001 and AMM 31-63-34-400-001.

(1) If the fault continues:

replace the FWC-2 [1WW2] AMM 31-53-34-000-001 and AMM 31-53-34-400-001.

(a) If the fault continues:

do a check and repair the wiring from DMC2 (1WT2) pins AD/8C, 8D to the FWC2 (1WW2) ASM 315205.

Subtask 31-63-00-740-335-A

B. Do the test given in Para. 3.B.

[Rev.8 from Aug 2018] 2026.04.04 04:40:06 UTC