Loss of the Battery 2 because of an Undervoltage or a Failure of the Voltage Sensing Circuit

TASK 24-38-00-810-833-A
Loss of the Battery 2 because of an Undervoltage or a Failure of the Voltage Sensing Circuit

1. Possible Causes

wiring
BCL-2 [1PB2]
P/BSW-ELEC/BAT 2 [7PB2]
C/B-ELEC/BAT BUS/REF/BCL2 [8PB2]
C/B-ELEC/BAT REF/BCL2 [9PB2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 24-38-00-810-835-A	Abnormal Power Consumption on the 28VDC HOT BUS (702PP)
AMM 24-38-00-710-001	Operational Test of the Battery Charge Limiter (BCL), (with the CFDS)
ASM 243802
AWM 243802
AMM 24-38-34-000-001	Removal of the Battery Charge Limiter (BCL)
AMM 24-38-34-400-001	Installation of the Battery Charge Limiter (BCL)
AMM 24-38-51-280-001	Removal of the Battery for Overhaul

3. Fault Confirmation
Subtask 24-38-00-710-106-A

A. 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.B. if amber crosses replace the voltage indication, do the trouble shooting given in Para. 4.C.

4. Fault Isolation
Subtask 24-38-00-865-058-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
105VU	ELEC/BAT REF/BCL2	9PB2	F02

Subtask 24-38-00-810-083-A

B. If the test confirms the fault:
(1) If the voltage read on the lower ECAM DU is equal to the voltage read on the voltmeter of the ELEC panel 35VU:
(a) Do the operational test of the BCL AMM 24-38-00-710-001.
1 If the test gives the maintenance message CHECK HOT BUS 2 POWER CONSUMPTION:

do the procedure given in (Ref. TSM TASK 24-38-00-810-835).

2 If the test result is TEST OK:

do a check and repair the wiring AWM 243802 between:
. the pin A/a of the BCL2 (1PB2) and the first terminal block,
. the pin A/Y of the BCL2 (1PB2) and the first terminal block.
do the removal and the restoration of the BAT2 (2PB2) AMM 24-38-51-280-001.

(2) If the voltage read on the lower ECAM DU is different from the voltage read on the voltmeter of the ELEC panel 35VU:

replace the BCL-2 [1PB2] AMM 24-38-34-000-001 and AMM 24-38-34-400-001.

(a) If the fault continues:

replace the P/BSW-ELEC/BAT 2 [7PB2] .

1 If the fault continues:

do a check of the wiring ASM 243802 between:
. the pin 2 of the circuit breaker (8PB2) and the pin A/D3 of the ELEC/BAT 2 pushbutton switch (7PB2)
. the pin A/D1 of the ELEC/BAT 2 pushbutton switch (7PB2) and the pin A/A of the BCL 2 (1PB2).

a If the wiring is not correct:

repair or replace as necessary.

b If the wiring is correct:

replace the C/B-ELEC/BAT BUS/REF/BCL2 [8PB2] .

Subtask 24-38-00-810-084-A

C. If the test confirms the fault:

do a check of the position of the circuit breaker (9PB2).

(1) If the circuit breaker is closed:

do a check for 28VDC at pin 2 of the circuit breaker (9PB2).

(a) If there is 28VDC:

do a check and repair the wiring ASM 243802 between:
. the pin 2 of the circuit breaker (9PB2) and the pin A/C3 of the ELEC/BAT 2 pushbutton switch (7PB2)
. the pin A/C1 of the ELEC/BAT 2 pushbutton switch (7PB2) and the pin A/C of the BCL2 (1PB2).

(b) If there is no 28VDC:

do a check and repair the wiring ASM 243802 between:
. the pin 1 of the circuit breaker (9PB2) and the 28VDC HOT BUS 704PP.

(2) If the circuit breaker is open:

close it.

(a) Do a check of the wiring for a short to ground between the pin 2 of the circuit breaker (9PB2) and the pin A/C3 of the ELEC/BAT 2 pushbutton switch (7PB2) ASM 243802.
1 If the wiring is not correct:

repair it.

2 If the wiring is correct:

replace the C/B-ELEC/BAT REF/BCL2 [9PB2] .

Subtask 24-38-00-710-107-A

D. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:26:49 UTC