Abnormal Power Consumption on the 28VDC HOT BUS (702PP)

TASK 24-38-00-810-835-A
Abnormal Power Consumption on the 28VDC HOT BUS (702PP)

1. Possible Causes

BAT-2 [2PB2]
BCL-2 [1PB2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 24-38-00-810-838-A	Incorrect Discharge of the Battery 2
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 24-38-51-000-001	Removal of the Batteries
AMM 24-38-51-400-001	Installation of the Batteries
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
AMM 31-32-00-860-004	Procedure to Get Access to the SYSTEM REPORT/TEST/ELEC Page
BAT2 - Ammeter Installation ** ON A/C NOT FOR ALL
BAT2 - Ammeter Installation ** ON A/C NOT FOR ALL

3. Fault Confirmation
Subtask 24-38-00-860-054-A

A. Job Set-Up
(1) Aircraft Maintenance Configuration
(a) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.
(b) On the overhead panel, on the ELEC panel 35VU, make sure that the BAT2 pushbutton switch is pushed (the OFF legend is off).
(c) Adjust the brightness of the MCDU screen.
(d) On the MCDU, get the SYSTEM REPORT/TEST/ELEC page AMM 31-32-00-860-004.

Subtask 24-38-00-865-060-A

B. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	COM/CIDS/DEU A BAT/LINE 2	145RH	N14
121VU	COM/CIDS/DEU A BAT/LINE 1	144RH	N13
** ON A/C NOT FOR ALL
121VU	COM/CIDS/DEU B/BAT	143RH	N12
** ON A/C NOT FOR ALL
121VU	ENGINE/ENG1 AND 2 FIRE EXTIG/BTL1/SQUIB/B	2WE1	Q44
** ON A/C ALL
121VU	ADIRS/ADIRU/2/28VDC	6FP2	N04
121VU	FLIGHT CONTROLS/WTB/FLP/SYS2	12CV	P20
121VU	FLIGHT CONTROLS/WTB/SLT/SYS2	11CV	P19
121VU	EIS/SLIDES/ARM AND WARN/GND	13WN	P10
121VU	EIS/HORN/SPLY	2WC	P09
** ON A/C NOT FOR ALL
121VU	ENGINE/ENG1 AND 2 FIRE EXTIG/BTL2/SQUIB/B	2WE1	Q44

Subtask 24-38-00-710-110-A

C. Do this test

NOTE: Wait at least 15 minutes and do this BITE test of the BCL2.

ACTION	RESULT
1.On the center pedestal, on the MCDU: push the line key adjacent to the BCL indication.	On the MCDU: the BCL page comes into view.
2.On the MCDU: push the line key adjacent to the TEST indication.	On the MCDU, on the BCL/TEST page: if the TEST OK message comes into view, stop the trouble shooting, if the CHECK HOT BUS 2 POWER CONSUMPTION message comes into view, continue the trouble shooting (refer to the paragraph that follows).

Subtask 24-38-00-860-055-A ** ON A/C NOT FOR ALL

D. Preparation of the Fault Isolation
(1) Make sure that OFF/NAV/ATT selector switches on the ADIRS CDU are in the OFF position.
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.
(3) Release BAT1 and BAT2 pushbutton switches.
(4) Make sure that the refuel/defuel control panel is closed.
(5) Make sure that the circuit breakers shown in the figure are closed.
(6) In the battery power center 105VU, install an ammeter as shown in the figure.

Subtask 24-38-00-860-055-B ** ON A/C NOT FOR ALL

D. Preparation of the Fault Isolation
(1) Make sure that OFF/NAV/ATT selector switches on the ADIRS MSU panel 41VU are in the OFF position.
(2) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.
(3) Release BAT1 and BAT2 pushbutton switches.
(4) Make sure that the refuel/defuel control panel is closed.
(5) Make sure that the circuit breakers shown in the figure are closed.
(6) In the battery power center 105VU, install an ammeter as shown in the figure.

4. Fault Isolation
Subtask 24-38-00-810-086-A

A. If the test gives the maintenance message CHECK HOT BUS 2 POWER CONSUMPTION:

read the value of the discharge current in the BAT 2 box on the ELEC page of the lower ECAM display unit:

NOTE: When you read the value of the discharge current, make sure that the BAT 2 contactor is open (on the ELEC page of the lower ECAM display unit).

(1) If the value of the discharge current is more than or equal to 1 ampere:

do a check of the current value with an ammeter (Ref. TSM TASK 24-38-00-810-838).

(2) If the value of the discharge current is less than 1 ampere:

replace the BAT-2 [2PB2] , AMM 24-38-51-000-001 and AMM 24-38-51-400-001,
wait at least 15 minutes and do the BITE test of the BCL2 as given in Para. 4C.

(a) If the BITE test gives the maintenance message CHECK HOT BUS 2 POWER CONSUMPTION:

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

(b) If the BITE test gives the maintenance message TEST OK:

make sure that after the subsequent flight, the maintenance message CHECK HOT BUS 1 POWER CONSUMPTION does not appear.

1 If the maintenance message CHECK HOT BUS 2 POWER CONSUMPTION appear:

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

Subtask 24-38-00-860-056-A

B. Preparation for the test
(1) Energize the aircraft electrical circuits
AMM 24-41-00-861-002.

Subtask 24-38-00-710-111-A

C. Do this test to make sure that the system operates correctly

NOTE: Wait at least 15 minutes and do this BITE test of the BCL2.

ACTION	RESULT
1.On the ELEC panel 35VU: push the BAT 2 pushbutton switch.	On the ELEC panel 35VU: the OFF legend of the BAT 2 pushbutton switch goes off.
2.On the center pedestal, on the MCDU: push the line key adjacent to the BCL indication.	On the MCDU: the BCL page comes into view.
3.On the MCDU: push the line key adjacent to the TEST indication.	On the MCDU, on the BCL/TEST page: the TEST OK message comes into view.

5. Close-up
Subtask 24-38-00-860-057-A

A. Put the aircraft back to its initial configuration.
(1) On the MCDU, push the line key adjacent to the RETURN indication until the MCDU MENU comes into view.
(2) Fully decrease the brightness of the MCDU screen (display off).
(3) De-energize the aircraft electrical circuits
AMM 24-41-00-862-002.

[Rev.8 from Aug 2018] 2026.04.04 04:39:03 UTC