DMU Receives No Data from the SDAC 1 or SDAC 2

TASK 31-36-00-810-834-A
DMU Receives No Data from the SDAC 1 or SDAC 2

1. Possible Causes

wiring
SDAC-1 [1WV1]
SDAC-2 [1WV2]
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 31-36-00-740-094-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, 6WV, 7WV, 8WV, 9WV on the panel 121VU and 2WV, 3WV, 5WV, 10WV, 12WV on the panel 49VU are closed during the test.

4. Fault Isolation
Subtask 31-36-00-810-074-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:

NO SDAC 1 DATA (BUS 1)
NO SDAC 2 DATA (BUS 1)
NO SDAC 1 DATA (BUS 2)
NO SDAC 2 DATA (BUS 2)

(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 SDAC-1 [1WV1] or SDAC-2 [1WV2] to the DMU [1TV] ASM 313701:

SDAC 1 Connector AB/8J to DMU Connector AA/6G and AA/6J
SDAC 1 Connector AB/8K to DMU Connector AA/6H and AA/6K
or
SDAC 2 Connector AB/8J to DMU Connector AB/6G and AB/6J
SDAC 2 Connector AB/8K to DMU Connector AB/6H and AB/6K

(3) If the fault continues:

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

Subtask 31-36-00-740-095-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