Failure of the External Power Wiring or Interlock Protection

TASK 24-41-00-810-819-A
Failure of the External Power Wiring or Interlock Protection

1. Possible Causes

wiring
GAPCU [24XG]

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 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)

3. Fault Confirmation
Subtask 24-41-00-710-069-A ** ON A/C NOT FOR ALL

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

4. Fault Isolation
Subtask 24-41-00-810-088-A ** ON A/C NOT FOR ALL

A. If it is not possible to connect the external power source to the aircraft electrical network and if the fault symptom is identified by the CFDS message WRG:EXT PWR PIN E INTERLOCK/ GAPCU (24XG):

do a check of the wiring of the external power interlock-control for an open circuit or a short circuit between the pin E and the cord plug of the external power source.

(1) If the wiring is not correct:

repair or replace as necessary.

(2) If the wiring is correct:

do a check of the wiring of the interlock control ASM 244101 for an open circuit, a short circuit or a short to ground between pin E of the external power receptacle (20XG) and pin B/11E of the GAPCU.

(a) If the wiring is not correct:

repair or replace as necessary.

(b) If the wiring is correct:

replace the GAPCU [24XG] AMM 24-41-34-000-001 and AMM 24-41-34-400-001.

Subtask 24-41-00-860-064-A ** ON A/C NOT FOR ALL

B. Do this procedure to make sure that the system operates correctly:
(1) Energize the Aircraft Electrical Circuits from the external power AMM 24-41-00-861-002.
(2) De-energize the aircraft electrical circuits from the external power AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:26:54 UTC