DOC AIRBUS | TSM A320FAircraft Electrical Circuits cannot be supplied from the APU GEN
TASK 24-23-00-810-806-A
Aircraft Electrical Circuits cannot be supplied from the APU GEN
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 24-23-00-710-059-A
Subtask 24-23-00-865-053-A
[Rev.8 from Aug 2018]
2026.04.04 04:26:39 UTC
Aircraft Electrical Circuits cannot be supplied from the APU GEN
1. Possible Causes
- MODULE DIODE UNIT [1164VD]
- wiring
- RELAY-APU AVAIL [6KD]
- diode module 1162VD
- GCU-APU [1XS]
- RELAY-APU GLC AUX CTL [4XS]
- RELAY-EPC AUX CTL [5XG]
- GLC-APU [3XS]
- EPC [3XG]
- P/BSW-ELEC/APU GEN [2XS]
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| TSM TASK 24-20-00-810-947-A | Failure of the Signal from the APU Control Relay to the GAPCU |
| ASM 242202 | |
| ASM 242302 | |
| AMM 24-23-34-000-001 | Removal of the GCU-APU |
| AMM 24-23-34-400-001 | Installation of the GCU-APU |
| AMM 24-23-55-000-001 | Removal of the APU GLC |
| AMM 24-23-55-400-001 | Installation of the APU GLC |
| AMM 24-41-00-861-002 | Energize the Aircraft Electrical Circuits from the External Power |
| AMM 24-41-55-000-001 | Removal of the External Power Contactor (EPC) |
| AMM 24-41-55-400-001 | Installation of the External Power Contactor (EPC) |
| ASM 496101 |
Subtask 24-23-00-710-059-A
A. Test
(1) Energize the aircraft electrical circuits from the external power AMM 24-41-00-861-002.
(2) Start the APU by external power AMM 24-41-00-861-002.
(3) Make sure that when the APU is started and the APU GEN pushbutton switch is pushed on the ELEC panel 35VU:
4. Fault Isolation(1) Energize the aircraft electrical circuits from the external power AMM 24-41-00-861-002.
(2) Start the APU by external power AMM 24-41-00-861-002.
(3) Make sure that when the APU is started and the APU GEN pushbutton switch is pushed on the ELEC panel 35VU:
- On the lower ECAM DU, on the ELEC page, in the APU GEN box, the voltage is 115VAC and the frequency is 400Hz.
- The ON legend goes off,
- The AVAIL legend comes on.
Subtask 24-23-00-865-053-A
A. Table of the circuit breakers used in this procedure:
Subtask 24-23-00-810-083-B ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 122VU | ELEC/GEN1/OFF/BTC1 SPLY | 5XU | T28 |
B. If the test confirms the result below when the APU is started and the APU GEN pushbutton switch (2XS) on the ELEC panel 35VU is pushed:
. The OFF legend of the APU GEN pushbutton switch is off, and
. The aircraft is energized by the APU generator for approximately three minutes.
(1) Replace MODULE DIODE UNIT [1164VD] .
Subtask 24-23-00-810-055-A ** ON A/C NOT FOR ALL . The OFF legend of the APU GEN pushbutton switch is off, and
. The aircraft is energized by the APU generator for approximately three minutes.
(1) Replace MODULE DIODE UNIT [1164VD] .
C. If the test confirms the results below when the APU is started and the APU GEN pushbutton switch (2XS) on the ELEC panel 35VU is pushed:
. The OFF legend of the APU GEN pushbutton switch is off, and
. The aircraft is not energized from the APU generator.
- Do a check for 28VDC at the pin 38 of the diode module 1162VD.
(a) If there is not 28VDC:
Subtask 24-23-00-810-055-B ** ON A/C NOT FOR ALL . The OFF legend of the APU GEN pushbutton switch is off, and
. The aircraft is not energized from the APU generator.
- Do a check of the wiring of the APU ready circuit ASM 496101, ASM 242302 and ASM 242202 between:
. Pin B/6J of the ECB (59KD) and pin X1 of the APU AVAIL relay (6KD)
. Pin X2 of the APU AVAIL relay (6KD) and ground
. Pin A/6A of the APU GCU (1XS) and pin A1 of the APU AVAIL relay (6KD)
. Pin A/13D of the APU GCU (1XS) and the first branch point
. Pin A2 of the APU AVAIL relay (6KD) and pin 37 of the diode module 1162VD
. Pin 38 of the diode module 1162VD and pin 2 of the ELEC/GEN1/OFF/BTC1 SPLY circuit breaker (5XU).
- Repair or replace as necessary.
- Replace RELAY-APU AVAIL [6KD] .
- Do a check for 28VDC at the pin 38 of the diode module 1162VD.
(a) If there is not 28VDC:
- Do a check and repair the wiring between the ELEC/GEN1/OFF/BTC1 SPLY circuit breaker (5XU) and the pin 38 of the diode module 1162VD ASM 242302.
- Replace diode module 1162VD and,
- Replace GCU-APU [1XS] AMM 24-23-34-000-001 and AMM 24-23-34-400-001.
- Replace RELAY-APU GLC AUX CTL [4XS] .
- Replace RELAY-EPC AUX CTL [5XG] .
- Replace GLC-APU [3XS] AMM 24-23-55-000-001 and AMM 24-23-55-400-001.
- Replace EPC [3XG] AMM 24-41-55-000-001 and AMM 24-41-55-400-001.
- Replace P/BSW-ELEC/APU GEN [2XS] .
- Do a check and repair the wiring ASM 242302 from:
. Pin B/3 of the APU GLC (3XS) to pin AA/12D of the APU GCU (1XS) and,
. Pin A/1 of the RELAY-APU GLC AUX CTL (4XS) to pin AA/12C of the APU GCU (1XS).
C. If the test confirms the results that follow when the APU is started and the ELEC/APU GEN pushbutton switch (2XS) on the ELEC panel 35VU is pushed:
. The OFF legend of the ELEC/APU GEN pushbutton switch is off, and
. The aircraft is not energized from the APU generator.
(1) On the panel 35VU, push the EXT PWR pushbutton switch:
(a) If the fault continues:
Subtask 24-23-00-710-060-A . The OFF legend of the ELEC/APU GEN pushbutton switch is off, and
. The aircraft is not energized from the APU generator.
(1) On the panel 35VU, push the EXT PWR pushbutton switch:
- The ON legend comes on,
- The AVAIL legend goes off.
(a) If the fault continues:
- Replace RELAY-APU GLC AUX CTL [4XS] .
- Replace RELAY-EPC AUX CTL [5XG] .
- Replace GLC-APU [3XS] AMM 24-23-55-000-001 and AMM 24-23-55-400-001.
- Replace EPC [3XG] AMM 24-41-55-000-001 and AMM 24-41-55-400-001.
- Replace P/BSW-ELEC/APU GEN [2XS] .
- Do a check and repair the wiring ASM 242302 from:
. Pin B/3 of the APU GLC (3XS) to pin AB/10J of the GAPCU (24XG) and,
. Pin X/1 of the RELAY-APU GLC AUX CTL (4XS) to pin AB/10J of the GAPCU (24XG).
D. Do the test given in Para. 3.