DMU Receives No Data from the FWC 1 or FWC 2

TASK 31-36-00-810-828-A
DMU Receives No Data from the FWC 1 or FWC 2

1. Possible Causes

wiring
FWC-1 [1WW1]
FWC-2 [1WW2]
DMU [1TV]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-36-00-710-001	Test of the DMU
AMM 31-36-34-000-001	Removal of the Data Management Unit (DMU)
AMM 31-36-34-400-001	Installation of the Data Management Unit (DMU)
ASM 313701
AMM 31-50-00-710-001	Ground Scanning of the Central Warning System

3. Fault Confirmation
Subtask 31-36-00-740-082-A ** ON A/C NOT FOR ALL

A. Do the DMU (1TV) fault monitoring test AMM 31-36-00-710-001.

NOTE: Make sure that the circuit breakers 1TV, 2WW on the panel 121VU and 3WW on the panel 49VU are closed during the test.

4. Fault Isolation
Subtask 31-36-00-810-068-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:

NO FWC 1 DATA, or
NO FWC 2 DATA

(1) Do the operational test of the Central Warning System AMM 31-50-00-710-001.

(a) If the test gives a different maintenance message, you can find the related trouble shooting procedure in the applicable Page Block 201.

(2) If the fault continues:

do a check and repair the wiring from the FWC-1 [1WW1] or FWC-2 [1WW2] to the DMU [1TV] ASM 313701:

FWC 1 Connector AB/12J to DMU Connector AA/6A
FWC 1 Connector AB/12K to DMU Connector AA/6B
or
FWC 2 Connector AB/12J to DMU Connector AB/6A
FWC 2 Connector AB/12K to DMU Connector AB/6B

(3) If the fault continues:

replace the DMU (1TV) AMM 31-36-34-000-001 and AMM 31-36-34-400-001.

Subtask 31-36-00-740-083-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

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