Loss of the BAT1 and BAT2 because of Undervoltage

TASK 24-38-00-810-848-A
Loss of the BAT1 and BAT2 because of Undervoltage

1. Possible Causes

P/BSW-APU/MASTER SW [14KD]
wiring
RELAY-BUS 1XP CTL [15XC]
RELAY-BUS 2XP CTL [16XC]
ADIRU-1 [1FP1]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 242402
ASM 243801
AWM 243801
ASM 243802
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

3. Fault Confirmation
Subtask 24-38-00-860-065-A

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.

Subtask 24-38-00-710-132-A

B. Test

ACTION	RESULT
1.On the ECAM control panel: push the ELEC key to get the ELEC page.	On the lower ECAM DU: if the voltage indication is shown in amber, do the trouble shooting given in Para. 4.A.

4. Fault Isolation
Subtask 24-38-00-865-059-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
122VU	ELEC/BUS/2XP/CTL	17XN2	V27
122VU	ELEC/AC/BUS1/CTL	17XN1	V25

Subtask 24-38-00-810-098-A

B. If the test confirms the fault:

On the overhead panel, on the APU section of panel 25VU, push and release the MASTER SW pushbutton switch (the FAULT legend comes on and then goes off).
Do a check for a ground signal at pin A/a of BCL1 (1PB1) ASM 243801 and at pin A/a of BCL2 (1PB2) ASM 243802.

(1) If there is a ground signal:

Replace the P/BSW-APU/MASTER SW [14KD] .

(a) If the fault continues:

Do a check and repair the wiring.

(2) If there is no ground signal:

On the rear circuit breaker panel 122VU, open circuit breakers 17XN1 and 17XN2.
Do a check for a ground signal at pin A/Y of BLC1 (1PB1) ASM 243801 and pin A/Y of BCL2 (1PB2) ASM 243802.

(a) If there is no ground signal:

Do a check for a ground signal at pin A/A3 ASM 243801 of the relay (15XC).

1 If there is a ground signal:

Repair the wiring AWM 243801 between the relay (15XC) and the first terminal block.

2 If there is no ground signal:

Do a check for a ground signal at the relay (15XC) pin A/A2 ASM 243801.

a If there is a ground signal:

Replace the RELAY-BUS 1XP CTL [15XC] .

b If there is no ground signal:

Do a check for a ground signal at pin A/A3 ASM 243801 of the relay (16XC).

* If there is a ground signal:
* - Repair the wiring ASM 243801 between pin A/A2 of the relay (15XC) and pin A/A3 of the relay (16XC).

* If there is no ground signal:
* - Do a check for a ground signal at pin A/A2 ASM 243801 of the relay (16XC).

** If there is a ground signal:
** - Replace the RELAY-BUS 2XP CTL [16XC] .

** If there is no ground signal:
** - Repair the wiring ASM 243801 between pin A/A2 of the relay (16XC) and the ground.

(b) If there is a ground signal:

Do a check for ground signal at pin A/g of BLC1 (1PB1) ASM 243801 and pin A/g of BCL2 (1PB2) ASM 243802.

1 If there is a ground signal:

Remove ADIRU-1 [1FP1] .

a If there is no ground signal after removal:

Replace ADIRU-1 [1FP1] .

b If there is a ground signal after removal:

Do a check and repair the wiring ASM 242402 between:
. Pin A/g of BCL1 and pin AA/2F of ADIRU1
. Pin A/g of BCL2 and pin AA/2F of ADIRU1.

Subtask 24-38-00-710-133-A

C. Do the test given in Para. 3.

5. Close-up
Subtask 24-38-00-860-066-A

A. Put the aircraft back to its initial configuration.
(1) On the rear circuit breaker panel 122VU, close the circuit breakers 17XN1 and 17XN2.
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:26:51 UTC