DMU Receives No Data from the CFDS

TASK 31-36-00-810-827-A
DMU Receives No Data from the CFDS

1. Possible Causes

wiring
CFDIU [1TW]
DMU [1TV]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-32-00-740-002	BITE Test of the Centralized Fault Display Interface Unit (CFDIU)
AMM 31-36-00-710-001	Test of the DMU
ASM 313601
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 31-36-00-740-080-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, 2TW, 8TW on the panel 121VU are closed during the test.

4. Fault Isolation
Subtask 31-36-00-810-067-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:

NO CDFS DATA, or
CFDS COMMUNIC FAIL

(1) Do the BITE Test of the Central Fault Display Interface System (CFDIU) AMM 31-32-00-740-002.

(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 CFDIU [1TW] to the DMU [1TV] ASM 313601:

CFDIU Connector AA/2B to DMU Connector AB/5C
CFDIU Connector AA/2C to DMU Connector AB/5D
CFDIU Connector AB/3F to DMU Connector AA/11E
CFDIU Connector AB/3G to DMU Connector AA/11F

(3) If the fault continues:

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

Subtask 31-36-00-740-081-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