DMU receives no Data from the FDIU

TASK 31-33-00-810-823-A
DMU receives no Data from the FDIU

1. Possible Causes

DMU [1TV]
FDIU [2TU]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-33-00-710-006	Operational Check of DFDR via MCDU
ASM 313301
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)

3. Fault Confirmation
Subtask 31-33-00-710-064-A ** ON A/C NOT FOR ALL

A. Do the test of the DMU AMM 31-36-00-710-001

NOTE: make sure that the circuit breakers 7TU and 4TV are closed.

4. Fault Isolation
Subtask 31-33-00-810-057-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenace message NO FDIU DATA:

do the FDIU (2TU) fault monitoring test via the MCDU AMM 31-33-00-710-006

(1) If the test gives a different maintenance message, do the trouble shooting procedure related to the maintenance message.
(2) If the fault continues:

replace the DMU [1TV] AMM 31-36-34-000-001 and AMM 31-36-34-400-001

(3) If the fault continues:

do a check and repair the wiring between:
FDIU [2TU] AB/9J and DMU [1TV] AA/5E,
FDIU [2TU] AB/9K and DMU [1TV] AA5F ASM 313301.

Subtask 31-33-00-710-065-A ** ON A/C NOT FOR ALL

B. Do the test as given in Para. 3 again to check the correct operation
(no maintenace message display).

[Rev.8 from Aug 2018] 2026.04.04 04:30:01 UTC