Emer. Lighting - Not all Cabin Emergency Lights come on during Simulation loss of 28 VDC

TASK 33-51-00-810-812-A
Emer. Lighting - Not all Cabin Emergency Lights come on during Simulation loss of 28 VDC

1. Possible Causes

POWER SUPPLY UNIT-EMERGENCY

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 24-41-00-862-002	De-energize the Aircraft Electrical Circuits Supplied from the External Power
ASM 335101
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 33-51-00-865-054-A

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	LIGHTING/EMER LT/CABIN	2WL	H06
49VU	LIGHTING/EMER LT/CABIN	1WL	H05
122VU	LIGHTING/CABIN/EMER/LT	3WL	V07

Subtask 33-51-00-860-058-A

B. Energize the aircraft electrical circuits
AMM 24-41-00-861-002.

Subtask 33-51-00-710-072-A

C. Operational Test

NOTE: Make sure that all cabin emergency lights have been tested and operate correctly.

(1) Do this test:

ACTION	RESULT
1.In the cockpit, on SIGNS panel 25VU: Set the SW-SIGNS/EMER EXIT LT (4WL) switch to the ARM position.
2.On circuit breaker panel 49VU: Open circuit breakers 1WL and 2WL.	In the cabin: Not all cabin emergency lights come on.

4. Fault Isolation
Subtask 33-51-00-810-061-A

A. Maintenance Action

NOTE: The combination of cabin emergency lights that do not come on shows you the EPSU which you must replace.

(1) If all to one POWER SUPPLY UNIT-EMERGENCY terminal related cabin emergency lights do not come on ASM 335101:

Replace the related POWER SUPPLY UNIT-EMERGENCY AMM 33-51-38-000-001 and AMM 33-51-38-400-001.

Subtask 33-51-00-710-073-A

B. Do the test given in Para. 3.

5. Close-up
Subtask 33-51-00-860-059-A

A. De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:32:08 UTC