Failure of the Status Circuit of the ELEC/APU GEN Pushbutton Switch

TASK 24-23-00-810-816-A
Failure of the Status Circuit of the ELEC/APU GEN Pushbutton Switch

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 242302
AMM 24-41-00-740-002	Operational Check of the GAPCU via the CFDS
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 24-23-00-740-054-A ** ON A/C NOT FOR ALL

A. Test
(1) Do the BITE test of the GAPCU AMM 24-41-00-740-002.

4. Fault Isolation
Subtask 24-23-00-865-052-A ** ON A/C NOT FOR ALL

A. Table of the circuit breakers used in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
122VU	ELEC/GAPCU	17XG	W24

Subtask 24-23-00-810-062-A ** ON A/C NOT FOR ALL

B. If the BITE test gives the maintenance message PB SW ELEC GEN APU (2XS)/ GAPCU (24XG):

NOTE: After you do the trouble shooting for this fault, open and close the circuit breaker 17XG to remove all 28VDC power supply from the GAPCU.

do a check of the wiring ASM 242302 for an open circuit or a short to ground between:
. pin A/1C of the GAPCU and pin A/D3 of the ELEC/APU GEN pushbutton switch
. pin A/4E of the GAPCU and pin A/D2 of the ELEC/APU GEN pushbutton switch
. pin A/2G of the GAPCU and pin A/D1 of the ELEC/APU GEN pushbutton switch.

(1) If the wiring is not correct:

(2) If the wiring is correct:

do a check of the contact of the ELEC/APU GEN pushbutton switch (2XS) ASM 242302 for correct operation between:
. pins A/D3 and A/D2 (normally closed)
. pins A/D3 and A/D1 (normally open).

(a) If the test is not OK:

(b) If the test is OK:

Subtask 24-23-00-740-055-A ** ON A/C NOT FOR ALL

C. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:26:40 UTC