Loss of the FAC 1 Output Bus by the DMC 3

TASK 31-63-00-810-944-A
Loss of the FAC 1 Output Bus by the DMC 3

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 226501
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
ASM 316201
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC

3. Fault Confirmation
Subtask 31-63-00-865-176-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	AUTO FLT/FAC1/28VDC	5CC1	B04
49VU	AUTO FLT/FAC1/26VAC	14CC1	B03

Subtask 31-63-00-740-298-A ** ON A/C NOT FOR ALL

B. Test
Do the EIS input test AMM 31-60-00-740-002.

Subtask 31-63-00-740-298-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 31-63-00-810-192-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message DMC 3 : NO FAC 1 DATA:

(1) If the fault continues:

do a check and repair the wiring from the DMC 3 (1WT3) pins AA/3C, 3D to the first terminal block ASM 316201.

(2) If the fault continues:

do a check and repair the wiring from the DMC 3 (1WT3) pin AB/1K to the first terminal block ASM 226501.

Subtask 31-63-00-810-192-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message FAC1(1CC1)/DMC3(1WT3):

(1) If the fault continues:

do a check and repair the wiring from the DMC 3 (1WT3) pins AA/4A, 4B to the first terminal block ASM 316201.

(2) If the fault continues:

do a check and repair the wiring from the DMC 3 (1WT3) pin AB/5C to the first terminal block ASM 226501.

Subtask 31-63-00-740-299-A

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

[Rev.8 from Aug 2018] 2026.04.04 04:30:48 UTC