Loss of the Bus Output from the Clock Detected by the CFDIU

TASK 31-21-00-810-804-A
Loss of the Bus Output from the Clock Detected by the CFDIU

1. Possible Causes

CLOCK [2FS]
CFDIU [1TW]
wiring
MMR-1 [40RT1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 312101
AMM 31-21-21-000-001	Removal of the Clock
AMM 31-21-21-400-001	Installation of the Clock
AMM 31-32-00-740-003	Ground Scanning of the CFDIU
AMM 31-32-34-000-001	Removal of the CFDIU
AMM 31-32-34-400-001	Installation of the CFDIU
AMM 34-36-31-000-001	Removal of the ILS Receiver
AMM 34-36-31-400-001	Installation of the ILS Receiver

3. Fault Confirmation
Subtask 31-21-00-865-052-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	CLOCK/NORM/SPLY	6FS	F11

Subtask 31-21-00-740-053-A

B. Do the ground scanning of the CFDIU AMM 31-32-00-740-003.

4. Fault Isolation
Subtask 31-21-00-810-053-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:

CLOCK

replace the CLOCK [2FS] , AMM 31-21-21-000-001 and AMM 31-21-21-400-001.

(1) If the fault continues:

replace the CFDIU [1TW] , AMM 31-32-34-000-001 and AMM 31-32-34-400-001.

(a) If the fault continues:

do a check and repair the wiring from the clock (2FS) connector A/W, X to the CFDIU (1TW) connector AA/9H, 9J ASM 312101.

Subtask 31-21-00-810-053-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:

CLOCK

replace the CLOCK [2FS] , AMM 31-21-21-000-001 and AMM 31-21-21-400-001.

(1) If the fault continues:

replace the CFDIU [1TW] , AMM 31-32-34-000-001 and AMM 31-32-34-400-001.

(2) If the fault continues:

replace the MMR-1 [40RT1] AMM 34-36-31-000-001 and AMM 34-36-31-400-001.

(3) If the fault continues

do a check and repair the wiring ASM 312101:

(a) from the Clock (2FS) connector A/W, X to the CFDIU (1TW) connector AA/9H, 9J.
(b) from the Clock (2FS) connector A/E, F to the MMR1 (40RT1) connector AB/9E, 9H.

Subtask 31-21-00-740-054-A

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

[Rev.8 from Aug 2018] 2026.04.04 04:29:48 UTC