W DOC AIRBUS | TSM A320F

Failure of the APU Generator PMG-Stator or its Wiring to the GAPCU

TASK 24-23-00-810-815-A
Failure of the APU Generator PMG-Stator or its Wiring to the GAPCU

1. Possible Causes
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
ASM 242301
AMM 24-23-51-000-001
Removal of the APU Generator
AMM 24-23-51-400-001
Installation of the APU Generator
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 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 24-23-00-869-054-A ** ON A/C NOT FOR ALL
A. Test
Not applicable.
NOTE: As the APU GEN was set to OFF because of a true failure, the fault confirmation is not necessary.
4. Fault Isolation
CAUTION: BEFORE YOU START THE CHECK OF IDG WIRING THAT INCLUDES CONNECTORS, EXAMINE EACH CONNECTOR TO MAKE SURE THAT THERE IS NO CONTAMINATION IN IT. IF YOU FIND CONTAMINATION, CLEAN THE CONNECTOR AND CONNECT IT AGAIN. IF THE FAILURE CONTINUES, DO THE TROUBLE SHOOTING PROCEDURE AS GIVEN BELOW.
Subtask 24-23-00-810-061-B ** ON A/C NOT FOR ALL
A. If the fault symptom is identified by the CFDS message GEN APU (8XS) PMG/ GAPCU (24XG):
   (1) If the CFDS message comes into view with the fault codes 122, 182, 197 or 199:
  • do a check of the resistance of the APU generator PMG-stator ASM 242301 between:
    . pins A/12 and A/13 of the APU generator (0.868 ohm plus or minus 0.156 ohm)
    . pins A/12 and A/14 of the APU generator (0.868 ohm plus or minus 0.156 ohm)
    . pins A/13 and A/14 of the APU generator (0.868 ohm plus or minus 0.156 ohm).
     (a) If the resistance values are out of the specified limits:
     (b) If the resistance values are in the specified limits:
  • do a check of the wiring ASM 242301 for a short to ground, a short circuit or an open circuit between:
    . pin A/12 of the APU generator and pin C/10 of the GAPCU
    . pin A/13 of the APU generator and pin C/11 of the GAPCU
    . pin A/14 of the APU generator and pin C/9 of the GAPCU
    . pins C/9, C/10, C/11 and pin C/7 of the GAPCU.
       1 If the wiring is not correct:
  • repair or replace as necessary.
       2 If the wiring is correct:
         a If the fault continues:
   (2) If the CFDS message comes into view with the fault code 67:
     (a) If the fault continues:
  • do a check of the wiring ASM 242301 for a short to ground, a short circuit or an open circuit between:
    . pin A/12 of the APU generator and pin C/10 of the GAPCU
    . pin A/13 of the APU generator and pin C/11 of the GAPCU
    . pin A/14 of the APU generator and pin C/9 of the GAPCU
    . pins C/9, C/10, C/11 and pin C/7 of the GAPCU.
       1 If the wiring is not correct:
  • repair or replace as necessary.
       2 If the wiring is correct:
Subtask 24-23-00-860-056-A ** ON A/C NOT FOR ALL
B. Make sure that the aircraft electrical circuits operate correctly in APU configuration.
   (1) Energize the aircraft electrical circuits from the APU AMM 24-41-00-861-002.
   (2) Let the APU generator operate for five minutes to make sure that it operates correctly.
   (3) De-energize the aircraft electrical circuits from the APU AMM 24-41-00-862-002.
[Rev.8 from Aug 2018] 2026.04.04 04:26:40 UTC
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