DMU Receives No Data from the FCU

TASK 31-36-00-810-825-A
DMU Receives No Data from the FCU

1. Possible Causes

wiring
FCU [2CA]
DMU [1TV]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 22-96-00-710-001	Operational Test of the AFS
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

3. Fault Confirmation
Subtask 31-36-00-740-076-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, 9CA2 on the panel 121VU and 9CA1 on the panel 49VU are closed during the test.

4. Fault Isolation
Subtask 31-36-00-810-065-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:

NO FCU BUS A DATA, or
NO FCU BUS B DATA, or
NO FCU 1 DATA, or
NO FCU 2 DATA

(1) Do the operatioal test of the AFS AMM 22-96-00-710-001.

(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 FCU [2CA] to the DMU [1TV] ASM 313701:

FCU Connector A/DD to DMU Connector AA/5A
FCU Connector A/EE to DMU Connector AA/5B
FCU Connector A/FF to DMU Connector AB/5A
FCU Connector A/GG to DMU Connector AB/5B

(3) If the fault continues:

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

Subtask 31-36-00-740-077-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:30:03 UTC