Loss of the FO ND DU or no Variation of Luminosity on the FO ND DU

TASK 31-63-00-810-979-A
Loss of the FO ND DU or no Variation of Luminosity on the FO ND DU

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-60-00-740-004	EIS System Test
AMM 31-63-22-000-001	Removal of the Display Unit
AMM 31-63-22-400-001	Installation of the Display Unit
AMM 31-63-34-000-001	Removal of the DMC
AMM 31-63-34-400-001	Installation of the DMC
ASM 316801

3. Fault Confirmation
Subtask 31-63-00-740-358-A ** ON A/C NOT FOR ALL

A. Test
Do the EIS system test AMM 31-60-00-740-004.

4. Fault Isolation
Subtask 31-63-00-810-232-A ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message DU ND FO(3WT2)/ND FO POT(8WT2):
(1) If there is no FO ND image:

on the panel 500VU, make sure that the FO ND potentiometer (8WT2) is in the center position
replace the ND-F/O [3WT2] , AMM 31-63-22-000-001 and AMM 31-63-22-400-001

(a) If the fault continues:

remove the panel 500VU
on the panel 500VU, do a continuity check between the pins L and N of the connector 2104VC-A

1 If there is continuity:

2 If there is no continuity:

remove the DMC-1 [1WT1] ,
remove the DMC-2 [1WT2]
remove the DMC-3 [1WT3] AMM 31-63-34-000-001
remove the ND-F/O [3WT2] AMM 31-63-22-000-001
check the wiring between the related LRU and the first terminal block ASM 316801
install the DMC-1 [1WT1] ,
install the DMC-2 [1WT2]
install the DMC-3 [1WT3] AMM 31-63-34-400-001
install the ND-F/O [3WT2] AMM 31-63-22-400-001
install the panel 500VU

(2) If there is no variation of luminosity on FO ND DU with the FO ND potentiometer (8WT2) on the brightness position:

remove the ND-F/O [3WT2] AMM 31-63-22-000-001
check the wiring between the FO ND DU (3WT2) and the FO ND potentiometer (8WT2) ASM 316801
install the FO ND DU (3WT2) AMM 31-63-22-400-001

5. Close-up
Subtask 31-63-00-740-359-A ** ON A/C NOT FOR ALL

A. Do the test given in Para. 3.A.

[Rev.8 from Aug 2018] 2026.04.04 04:30:50 UTC