Failure of EPSU 12WL to communicate with the CIDS

TASK 33-51-00-810-859-A
Failure of EPSU 12WL to communicate with the CIDS

1. Possible Causes

EPSU [12WL]
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 33-51-00-710-001	Operational Test of the Emergency Lights
ASM 335101
ASM 335102
AMM 33-51-38-000-001	Removal of the Emergency Power-Supply Unit (EPSU)
AMM 33-51-38-400-001	Installation of the Emergency Power-Supply Unit (EPSU)

3. Fault Confirmation

CAUTION: DO NOT USE THE TEACH-IN PROCEDURE AS AN ALTERNATIVE FOR TROUBLESHOOTING. A TEACH-IN PROCEDURE IS NOT A RESET PROCEDURE. BEFORE YOU DO A TEACH-IN PROCEDURE, MAKE SURE THAT YOU CORRECTED ALL FAILURES. IF YOU DO NOT OBEY THIS, FAILURES CAN CAUSE A MALFUNCTION OF THE CABIN EMERGENCY LIGHTING SYSTEM.

Subtask 33-51-00-710-162-A ** ON A/C NOT FOR ALL

A. Do the operational test of the emergency lights with the MCDU AMM 33-51-00-710-001.

4. Fault Isolation
Subtask 33-51-00-810-174-A ** ON A/C NOT FOR ALL

A. If the test gives a different maintenance message, do the trouble shooting procedure related to the maintenance message.

Subtask 33-51-00-810-175-A ** ON A/C NOT FOR ALL

B. If the operational test gives the maintenance message:
(1) EPSU(12WL)EMER R/DEU B(300RH6):

replace the EPSU [12WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.

(a) If the fault continues:

do a check and repair the wiring between:
EPSU 12WL pin -I and DEU-B 300RH6 pin B25.
EPSU 12WL pin -P and DEU-B 300RH6 pin B27.
EPSU 12WL pin X and DEU-B 300RH6 pin B26 ASM 335102.

(b) If the fault continues:

do a check of the electrical connections of the escape slide ASM 335101.

Subtask 33-51-00-710-163-A ** ON A/C NOT FOR ALL

C. Do the test given in Para. 3.

5. Close-up
Subtask 33-51-00-860-114-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.

[Rev.8 from Aug 2018] 2026.04.04 04:32:12 UTC