The EXT PWR/NOT IN USE Indicator Light Stays off when the EXT PWR Energizes the Aircraft

TASK 24-40-00-810-809-A
The EXT PWR/NOT IN USE Indicator Light Stays off when the EXT PWR Energizes the Aircraft

1. Possible Causes

wiring
IND LT-EXT PWR/NOT IN USE [8XG]
CNTOR-AC GND SVCE SPLY [12XX]
EPC [3XG]
EGIU-1 [22XU1]
P/BSW-ELEC/EXT PWR [10XG]
lamp
GAPCU [24XG]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 24-22-33-000-001	Removal of the EGIU-1(2)
AMM 24-22-33-400-002	Installation of the EGIU-1(2)
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 244101
AMM 24-41-34-000-001	Removal of the Ground Power Control Unit (GPCU)
AMM 24-41-34-400-001	Installation of the Ground Power Control Unit (GPCU)
AMM 24-41-55-000-001	Removal of the External Power Contactor (EPC)
AMM 24-41-55-400-001	Installation of the External Power Contactor (EPC)
AMM 24-42-55-000-001	Removal of the Contactors
AMM 24-42-55-400-001	Installation of the Contactors

3. Fault Confirmation
Subtask 24-40-00-710-056-A

A. Test
(1) Energize the aircraft electrical circuits from the external power AMM 24-41-00-861-002

NOTE: Energization of the aircraft is correct but, during the procedure given at Para. 3.D., make sure that:

on the external power panel 108VU: the EXT PWR/NOT IN USE indicator light stays off and the EXT PWR/AVAIL caution light comes on
on the ELEC panel 35VU: the AVAIL legend of the EXT PWR pushbutton switch comes on.

4. Fault Isolation
Subtask 24-40-00-810-058-A ** ON A/C NOT FOR ALL

A. If the test confirms the fault:

on the external power panel 108VU, push the LIGHT TEST pushbutton switch (34LP) to do a test of the lights of the external power panel 108VU.

(1) If the EXT PWR/NOT IN USE indicator light comes on:

do a check of the wiring between the pin 2 of the circuit breaker (6XG) and the pin 2 of the EXT PWR/NOT IN USE indicator light (8XG) ASM 244101.

(a) If there is no continuity:

repair the wiring.

(b) If there is continuity:

replace the IND LT-EXT PWR/NOT IN USE [8XG] .

1 If the fault continues:

replace the CNTOR-AC GND SVCE SPLY [12XX] AMM 24-42-55-000-001 and AMM 24-42-55-400-001.

2 If the fault continues:

replace the EPC [3XG] AMM 24-41-55-000-001 and AMM 24-41-55-400-001.

3 If the fault continues:

replace the EGIU-1 [22XU1] AMM 24-22-33-000-001 and AMM 24-22-33-400-002.

4 If the fault continues:

replace the P/BSW-ELEC/EXT PWR [10XG] .

a If the fault continues:

do a check and repair the wiring ASM 244101 between:
. pin A/X2 of the EPC auxiliary control relay (5XG) and pin AB/3C of the EGIU 1 (22XU1)
. pin 2 of the circuit breaker (11XG) and pin AB/5C of the EGIU 1 (22XU1)
. pin AB/5C of the EGIU 1 (22XU1) and pin A/B1 of the ELEC/EXT PWR pushbutton switch (10XG)
. pin AB/4C of the EGIU 1 (22XU1) and pin A/B3 of the ELEC/EXT PWR pushbutton switch (10XG).

(2) If the EXT PWR/NOT IN USE indicator light (8XG) stays off:

replace the lamp of the EXT PWR/NOT IN USE indicator light (8XG).

(a) If the fault continues:

do a check of the wiring ASM 244101 between:
. pins 4 and 1 of the EXT PWR/NOT IN USE indicator light (8XG)
. pin 5 of the EXT PWR/NOT IN USE indicator light (8XG) and the first terminal.

1 If there is no continuity:

repair the wiring.

2 If there is continuity:

replace the IND LT-EXT PWR/NOT IN USE [8XG] .

Subtask 24-40-00-810-058-B ** ON A/C NOT FOR ALL