W DOC AIRBUS | TSM A320F

EPSU - Internal Load Fault Message

TASK 33-51-00-810-807-A
EPSU - Internal Load Fault Message

1. Possible Causes
  • lamp(s)
  • LIGHT-EMERGENCY, CABIN
  • wiring
  • POWER-EMERGENCY SUPPLY [10WL]
  • SIGN-EXIT LOCATION
  • SIGN-EXIT MARKING
  • lights, signs and markers
  • SEAT/WALL-MOUNTED EMERGENCY LIGHT
  • SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHT
  • EXIT MARKER
  • EPSU [11WL]
  • ESCAPE HATCH-HANDLE LIGHT
  • EPSU [12WL]
  • EPSU [13WL]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 33-51-00-810-808-A
EPSU - External Load Fault
AMM 33-51-00-710-001
Operational Test of the Emergency Lights
AMM 33-51-00-710-009
Check of all the Cabin Lights and Signs for Correct Illumination
ASM 335101
ASM 335102
ASM 335104
AMM 33-51-11-000-001
Removal of the Cabin Emergency Lights
AMM 33-51-11-400-001
Installation of the Cabin Emergency Light
AMM 33-51-13-000-001
Removal of the Cabin Wall-Mounted Emergency-Exit-Markers
AMM 33-51-13-400-001
Installation of the Cabin Wall-Mounted Emergency-Exit-Markers
AMM 33-51-16-000-001
Removal of the Emergency Exit Sign
AMM 33-51-16-400-001
Installation of the Emergency Exit Sign
AMM 33-51-17-000-001
Removal of the Emergency Exit Location-Sign
AMM 33-51-17-400-001
Installation of the Emergency Exit Location-Sign
AMM 33-51-18-000-001
Removal of the Seat/Wall-Mounted Emergency-Exit Location-Light
AMM 33-51-18-400-001
Installation of the Seat/Wall-Mounted Emergency-Exit Location-Light
AMM 33-51-19-000-003
Removal of the Seat/Wall-Mounted Emergency Light
AMM 33-51-19-400-003
Installation of the Seat/Wall-Mounted Emergency Light
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 33-51-00-710-062-A ** ON A/C NOT FOR ALL
A. Do the operational test of the emergency lighting through the CIDS AMM 33-51-00-710-001.
4. Fault Isolation
Subtask 33-51-00-810-056-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 33-51-00-810-068-A ** ON A/C NOT FOR ALL
B. If the test gives the maintenance message EPSU INT LOAD FWD L, do the operational test of the emergency cabin lights and signs AMM 33-51-00-710-009.
NOTE: The time to do this test must not be more than 1 minute. This is to prevent the discharge of the emergency lighting batteries.
   (1) If one or more lamps of the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related LIGHT-EMERGENCY, CABIN ASM 335101.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    - POWER SUPPLY UNIT-EMERGENCY (10WL) connector A/E or G and the related LIGHT-EMERGENCY, CABIN
    - related LIGHT-EMERGENCY, CABIN and GND ASM 335101.
   (2) If all the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
   (3) If one or more lamps of the SIGNS-EXIT LOCATION or the SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING ASM 335101.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    - POWER SUPPLY UNIT-EMERGENCY (10WL) connector A/N or R and the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING
    - related SIGN-EXIT LOCATION or SIGN-EXIT MARKING and GND ASM 335101.
   (4) If all the SIGNS-EXIT LOCATION and the SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
     (a) If the fault continues:
  • do a check and repair the wiring between the:
    - POWER SUPPLY UNIT-EMERGENCY (10WL) connector A/<F and the Relay (8WL) connector A/2 ASM 335101 and ASM 335101.
   (5) If all the lights and signs related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
     (a) If the fault continues:
     (b) If the fault continues:
  • do a check for a short to ground and repair the wiring if necessary ASM 335101 and ASM 335104:
    from EPSU (10WL) pin E to the connector(s) of the related signs and lights,
    from EPSU (10WL) pin G to the connector(s) of the related signs and lights,
    from EPSU (10WL) pin N to the connector(s) of the related signs and lights,
    from EPSU (10WL) pin R to the connector(s) of the related signs and lights,
  • if you find a short to ground in the wiring, replace the POWER-EMERGENCY SUPPLY [10WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.
     (c) If the fault continues:
Subtask 33-51-00-810-071-A ** ON A/C NOT FOR ALL
C. If the test gives the maintenance message EPSU INT LOAD EMER L, do the operational test of the emergency cabin lights and signs AMM 33-51-00-710-009.
NOTE: The time to do this test must not be more than 1 minute. This is to prevent the discharge of the emergency lighting batteries.
   (1) If one or more lamps of the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related LIGHT-EMERGENCY, CABIN ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (11WL) connector A/E or G and the related LIGHT-EMERGENCY, CABIN,
    related LIGHT-EMERGENCY, CABIN and GND ASM 335102.
   (2) If all LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
   (3) If one or more lamps of the SIGNS-EXIT LOCATION or SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (11WL) connector A/N or R and the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING,
    related SIGN-EXIT LOCATION or SIGN-EXIT MARKING and GND ASM 335102.
   (4) If one or more lamps of the ESCAPE HATCH-HANDLE LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related ESCAPE HATCH-HANDLE LIGHT ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (11WL) connector A/N or R and the related ESCAPE HATCH-HANDLE LIGHT,
    related ESCAPE HATCH-HANDLE LIGHT and GND ASM 335102.
   (5) If all SIGNS-EXIT LOCATION, SIGNS-EXIT MARKING and ESCAPE HATCH-HANDLE LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
     (a) If the fault continues:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (11WL) connector A/<F and the Relay (8WL) connector A/2 ASM 335101 and ASM 335102.
   (6) If all lights and signs related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
     (a) If the fault continues:
     (b) If the fault continues:
  • do a check for a short to ground and repair the wiring if necessary ASM 335101 and ASM 335104:
    from EPSU (11WL) pin E to the connector(s) of the related signs and lights,
    from EPSU (11WL) pin G to the connector(s) of the related signs and lights,
    from EPSU (11WL) pin N to the connector(s) of the related signs and lights,
    from EPSU (11WL) pin R to the connector(s) of the related signs and lights,
  • if you find a short to ground in the wiring, replace the EPSU [11WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.
     (c) If the fault continues:
Subtask 33-51-00-810-070-A ** ON A/C NOT FOR ALL
D. If the test gives the maintenance message EPSU INT LOAD EMER R, do the operational test of the emergency cabin lights and signs AMM 33-51-00-710-009.
NOTE: The time to do this test must not be more than 1 minute. This is to prevent the discharge of the emergency lighting batteries.
   (1) If one or more lamps of the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related LIGHT-EMERGENCY, CABIN ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (12WL) connector A/E or G and the related LIGHT-EMERGENCY, CABIN,
    related LIGHT-EMERGENCY, CABIN and GND ASM 335102.
   (2) If all LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
   (3) If one or more lamps of the SIGNS-EXIT LOCATION or SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (12WL) connector A/N or R and the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING,
    related SIGN-EXIT LOCATION or SIGN-EXIT MARKING and GND ASM 335102.
   (4) If one or more lamps of the ESCAPE HATCH-HANDLE LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related ESCAPE HATCH-HANDLE LIGHT ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (12WL) connector A/N or R and the related ESCAPE HATCH-HANDLE LIGHT,
    related ESCAPE HATCH-HANDLE LIGHT and GND ASM 335102.
   (5) If all SIGNS-EXIT LOCATION, SIGNS-EXIT MARKING and ESCAPE HATCH-HANDLE LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
     (a) If the fault continues:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (12WL) connector A/<F and the Relay (8WL) connector A/2 ASM 335101 and ASM 335102.
   (6) If all lights and signs related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
     (a) If the fault continues:
     (b) If the fault continues:
  • do a check for a short to ground and repair the wiring if necessary ASM 335101 and ASM 335104:
    from EPSU (12WL) pin E to the connector(s) of the related signs and lights,
    from EPSU (12WL) pin G to the connector(s) of the related signs and lights,
    from EPSU (12WL) pin N to the connector(s) of the related signs and lights,
    from EPSU (12WL) pin R to the connector(s) of the related signs and lights,
  • if you find a short to ground in the wiring, replace the EPSU [12WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.
     (c) If the fault continues:
Subtask 33-51-00-810-068-L ** ON A/C NOT FOR ALL
E. If the test gives the maintenance message EPSU INT LOAD FWD L, do the operational test of the emergency cabin lights and signs AMM 33-51-00-710-009.
NOTE: The time to do this test must not be more than 1 minute. This is to prevent the discharge of the emergency lighting batteries.
   (1) If one or more lamps of the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related LIGHT-EMERGENCY, CABIN ASM 335101.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (10WL) connector A/E or G and the related LIGHT-EMERGENCY, CABIN,
    related LIGHT-EMERGENCY, CABIN and GND ASM 335101.
   (2) If all LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
   (3) If one or more lamps of the SEAT/WALL-MOUNTED EMERGENCY LIGHTS or SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHTS or EXIT MARKERS related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SEAT/WALL-MOUNTED EMERGENCY LIGHT or SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHTS or EXIT MARKER ASM 335104.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (10WL) connector A/<B or <J and the related SEAT/WALL-MOUNTED EMERGENCY LIGHT or SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHT or EXIT MARKER,
    related SEAT/WALL-MOUNTED EMERGENCY LIGHT or SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHT or EXIT MARKER and GND ASM 335104.
   (4) If all SEAT/WALL-MOUNTED EMERGENCY LIGHTS and SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHTS and EXIT MARKERS related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
   (5) If one or more lamps of the SIGNS-EXIT LOCATION or SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING ASM 335101.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (10WL) connector A/N or R and the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING,
    related SIGN-EXIT LOCATION or SIGN-EXIT MARKING and GND ASM 335101.
   (6) If all SIGNS-EXIT LOCATION and SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
     (a) If the fault continues:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (10WL) connector A/<F and the Relay (8WL) connector A/2 ASM 335101 and ASM 335101.
   (7) If all lights, signs and markers related to the POWER SUPPLY UNIT-EMERGENCY (10WL) do not come on:
     (a) If the fault continues:
     (b) If the fault continues:
  • do a check for a short to ground and repair the wiring if necessary ASM 335101 and ASM 335104:
    from EPSU (10WL) pin E to the connector(s) of the related signs and lights,
    from EPSU (10WL) pin G to the connector(s) of the related signs and lights,
    from EPSU (10WL) pin N to the connector(s) of the related signs and lights,
    from EPSU (10WL) pin R to the connector(s) of the related signs and lights,
  • if you find a short to ground in the wiring, replace the POWER-EMERGENCY SUPPLY [10WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.
     (c) If the fault continues:
Subtask 33-51-00-810-071-L ** ON A/C NOT FOR ALL
F. If the test gives the maintenance message EPSU INT LOAD EMER L, do the operational test of the emergency cabin lights and signs AMM 33-51-00-710-009.
NOTE: The time to do this test must not be more than 1 minute. This is to prevent the discharge of the emergency lighting batteries.
   (1) If one or more lamps of the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related LIGHT-EMERGENCY, CABIN ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (11WL) connector A/E or G and the related LIGHT-EMERGENCY, CABIN,
    related LIGHT-EMERGENCY, CABIN and GND ASM 335102.
   (2) If all LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
   (3) If one or more lamps of the SEAT/WALL-MOUNTED EMERGENCY LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (11WL) connector A/<B or <J and the related SEAT/WALL-MOUNTED EMERGENCY LIGHT,
    related SEAT/WALL-MOUNTED EMERGENCY LIGHT and GND ASM 335104, ASM 335104 and ASM 335104.
   (4) If all SEAT/WALL-MOUNTED EMERGENCY LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
   (5) If one or more lamps of the SIGNS-EXIT LOCATION or SIGNS-EXIT MARKING or ESCAPE HATCH-HANDLE LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING or ESCAPE HATCH-HANDLE LIGHT ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (11WL) connector A/N or R and the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING or ESCAPE HATCH-HANDLE LIGHT,
    related SIGN-EXIT LOCATION or SIGN-EXIT MARKING or ESCAPE HATCH-HANDLE LIGHT and GND ASM 335102.
   (6) If all SIGNS-EXIT LOCATION and SIGNS-EXIT MARKING and ESCAPE HATCH-HANDLE LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
     (a) If the fault continues:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (11WL) connector A/<F and the Relay (8WL) connector A/2 ASM 335101 and ASM 335102.
   (7) If all lights and signs related to the POWER SUPPLY UNIT-EMERGENCY (11WL) do not come on:
     (a) If the fault continues:
     (b) If the fault continues:
  • do a check for a short to ground and repair the wiring if necessary ASM 335101 and ASM 335104:
    from EPSU (11WL) pin E to the connector(s) of the related signs and lights,
    from EPSU (11WL) pin G to the connector(s) of the related signs and lights,
    from EPSU (11WL) pin N to the connector(s) of the related signs and lights,
    from EPSU (11WL) pin R to the connector(s) of the related signs and lights,
  • if you find a short to ground in the wiring, replace the EPSU [11WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.
     (c) If the fault continues:
Subtask 33-51-00-810-070-L ** ON A/C NOT FOR ALL
G. If the test gives the maintenance message EPSU INT LOAD EMER R, do the operational test of the emergency cabin lights and signs AMM 33-51-00-710-009.
NOTE: The time to do this test must not be more than 1 minute. This is to prevent the discharge of the emergency lighting batteries.
   (1) If one or more lamps of the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related LIGHT-EMERGENCY, CABIN ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (12WL) connector A/E or G and the related LIGHT-EMERGENCY, CABIN,
    related LIGHT-EMERGENCY, CABIN and GND ASM 335102.
   (2) If all LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
   (3) If one or more lamps of the SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHTS or EXIT MARKERS related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHT or EXIT MARKER ASM 335104.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (12WL) connector A/<B or <J and the related SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHT or EXIT MARKER,
    related SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHT or EXIT MARKER and GND ASM 335104.
   (4) If all SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHTS and EXIT MARKERS related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
   (5) If one or more lamps of the SIGNS-EXIT LOCATION or SIGNS-EXIT MARKING or ESCAPE HATCH-HANDLE LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING or ESCAPE HATCH-HANDLE LIGHT ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (12WL) connector A/N or R and the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING or ESCAPE HATCH-HANDLE LIGHT,
    related SIGN-EXIT LOCATION or SIGN-EXIT MARKING or ESCAPE HATCH-HANDLE LIGHT and GND ASM 335102.
   (6) If all SIGNS-EXIT LOCATION and SIGNS-EXIT MARKING and ESCAPE HATCH-HANDLE LIGHTS related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
     (a) If the fault continues:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (12WL) connector A/<F and the Relay (8WL) connector A/2 ASM 335101 and ASM 335102.
   (7) If all lights, signs and markers related to the POWER SUPPLY UNIT-EMERGENCY (12WL) do not come on:
     (a) If the fault continues:
     (b) If the fault continues:
  • do a check for a short to ground and repair the wiring if necessary ASM 335101 and ASM 335104:
    from EPSU (12WL) pin E to the connector(s) of the related signs and lights,
    from EPSU (12WL) pin G to the connector(s) of the related signs and lights,
    from EPSU (12WL) pin N to the connector(s) of the related signs and lights,
    from EPSU (12WL) pin R to the connector(s) of the related signs and lights,
  • if you find a short to ground in the wiring, replace the EPSU [12WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.
     (c) If the fault continues:
Subtask 33-51-00-810-069-A ** ON A/C NOT FOR ALL
H. If the test gives the maintenance message EPSU INT LOAD AFT L, do the operational test of the emergency cabin lights and signs AMM 33-51-00-710-009.
NOTE: The time to do this test must not be more than 1 minute. This is to prevent the discharge of the emergency lighting batteries.
   (1) If one or more lamps of the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related LIGHT-EMERGENCY, CABIN ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (13WL) connector A/E or G and the related LIGHT-EMERGENCY, CABIN,
    related LIGHT-EMERGENCY, CABIN and GND ASM 335102.
   (2) If all LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
   (3) If one or more lamps of the SIGNS-EXIT LOCATION or SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (13WL) connector A/N or R and the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING,
    related SIGN-EXIT LOCATION or SIGN-EXIT MARKING and GND ASM 335102.
   (4) If all SIGNS-EXIT LOCATION and SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
     (a) If the fault continues:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (13WL) connector A/<F and the Relay (8WL) connector A/2 ASM 335101 and ASM 335102.
   (5) If all lights and signs related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
     (a) If the fault continues:
     (b) If the fault continues:
  • do a check for a short to ground and repair the wiring if necessary ASM 335101 and ASM 335104:
    from EPSU (13WL) pin E to the connector(s) of the related signs and lights,
    from EPSU (13WL) pin G to the connector(s) of the related signs and lights,
    from EPSU (13WL) pin N to the connector(s) of the related signs and lights,
    from EPSU (13WL) pin R to the connector(s) of the related signs and lights,
  • if you find a short to ground in the wiring, replace the EPSU [13WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.
     (c) If the fault continues:
Subtask 33-51-00-810-069-L ** ON A/C NOT FOR ALL
H. If the test gives the maintenance message EPSU INT LOAD AFT L, do the operational test of the emergency cabin lights and signs AMM 33-51-00-710-009.
NOTE: The time to do this test must not be more than 1 minute. This is to prevent the discharge of the emergency lighting batteries.
   (1) If one or more lamps of the LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related LIGHT-EMERGENCY, CABIN ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (13WL) connector A/E or G and the related LIGHT-EMERGENCY, CABIN,
    related LIGHT-EMERGENCY, CABIN and GND ASM 335102.
   (2) If all LIGHTS-EMERGENCY, CABIN related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
   (3) If one or more lamps of the SEAT/WALL-MOUNTED EMERGENCY LIGHTS or SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHTS or EXIT MARKERS related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SEAT/WALL-MOUNTED EMERGENCY LIGHT or SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHTS or EXIT MARKER ASM 335104.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (13WL) connector A/<B or <J and the related SEAT/WALL-MOUNTED EMERGENCY LIGHT or SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHT or EXIT MARKER,
    related SEAT/WALL-MOUNTED EMERGENCY LIGHT or SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHT or EXIT MARKER and GND ASM 335104.
   (4) If all SEAT/WALL-MOUNTED EMERGENCY LIGHTS and SEAT/WALL-MOUNTED EMERGENCY-EXIT-LOCATION LIGHTS and EXIT MARKERS related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
   (5) If one or more lamps of the SIGNS-EXIT LOCATION or SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
  • replace the lamp(s).
     (a) If the fault continues:
  • do a check for approx. 6 VDC at the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING ASM 335102.
       1 If there are approx. 6 VDC:
       2 If there are no 6 VDC:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (13WL) connector A/N or R and the related SIGN-EXIT LOCATION or SIGN-EXIT MARKING,
    related SIGN-EXIT LOCATION or SIGN-EXIT MARKING and GND ASM 335102.
   (6) If all SIGNS-EXIT LOCATION and SIGNS-EXIT MARKING related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
     (a) If the fault continues:
  • do a check and repair the wiring between the:
    POWER SUPPLY UNIT-EMERGENCY (13WL) connector A/<F and the Relay (8WL) connector A/2 ASM 335101 and ASM 335102.
   (7) If all lights, signs and markers related to the POWER SUPPLY UNIT-EMERGENCY (13WL) do not come on:
     (a) If the fault continues:
     (b) If the fault continues:
  • do a check for a short to ground and repair the wiring if necessary ASM 335101 and ASM 335104:
    from EPSU (13WL) pin E to the connector(s) of the related signs and lights,
    from EPSU (13WL) pin G to the connector(s) of the related signs and lights,
    from EPSU (13WL) pin N to the connector(s) of the related signs and lights,
    from EPSU (13WL) pin R to the connector(s) of the related signs and lights,
  • if you find a short to ground in the wiring, replace the EPSU [13WL] AMM 33-51-38-000-001 and AMM 33-51-38-400-001.
     (c) If the fault continues:
Subtask 33-51-00-710-063-A ** ON A/C NOT FOR ALL
I. Do the test given in Para. 3.
5. Close-up
Subtask 33-51-00-860-070-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
[Rev.8 from Aug 2018] 2026.04.04 04:40:23 UTC
"AVIABRAIN" 2025