W DOC AIRBUS | TSM A320F

APU Power Supply to the FDU Channel A and/or B

TASK 26-13-00-810-804-A
APU Power Supply to the FDU Channel A and/or B

1. Possible Causes
  • FDU-APU [13WG]
  • wiring
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 26-13-00-710-002
BITE Test of the APU Fire and Overheat Detection System
ASM 261301
AMM 26-13-34-000-001
Removal of the APU Fire-Detection Unit (FDU)
AMM 26-13-34-400-001
Installation of the APU Fire-Detection Unit (FDU)
3. Fault Confirmation
Subtask 26-13-00-710-056-A
A. Do the BITE test of the APU fire and overheat detection system AMM 26-13-00-710-002.
4. Fault Isolation
Subtask 26-13-00-810-066-A
A. If the test gives a different maintenance message:
  • Do the trouble shooting procedure related to the maintenance message.
Subtask 26-13-00-810-060-A
B. If the test gives the maintenance message CHECK FDU APU LOOP A/B NO DATA FROM FDU APU
  • do a check for 28 VDC power supply to the FDU-APU [13WG] connector A/A ASM 261301.
   (1) If there is no 28 VDC:
  • do a check and repair the wiring if necessary between the:
    FDU (13WG) connector A/A and CB (1WG),
    FDU (13WG) connector B/N and GND,
    FDU (13WG) connector B/B and GND,
    FDU (13WG) connector A/B and GND ASM 261301.
   (2) If there is approx. 28 VDC:
Subtask 26-13-00-810-061-A ** ON A/C NOT FOR ALL
C. If the test gives the maintenance message:
CHECK FDU APU SUPPLY
and/or
POWER SUPPLY INTERRUPT

  • do a check for 28 VDC power supply to the FDU-APU [13WG] connector B/A ASM 261301.
   (1) If there is no 28 VDC:
  • do a check and repair the wiring if necessary between the:
    FDU (13WG) connector B/A and CB (2WG),
    FDU (13WG) connector B/N and GND,
    FDU (13WG) connector B/B and GND,
    FDU (13WG) connector A/B and GND ASM 261301.
   (2) If there is approx. 28 VDC:
Subtask 26-13-00-810-061-B ** ON A/C NOT FOR ALL
C. If the test gives the maintenance message:
CHECK FDU APU CHAN B SUPPLY
and/or
POWER SUPPLY INTERRUPT

  • Do a check for 28 VDC power supply to the FDU APU (13WG) connector B/A ASM 261301.
   (1) If there is no 28 VDC:
  • Do a check and repair the wiring if necessary between the:
    FDU (13WG) connector B/A and CB (2WG),
    FDU (13WG) connector B/N and GND,
    FDU (13WG) connector B/B and GND,
    FDU (13WG) connector A/B and GND ASM 261301.
   (2) If there is approximately 28 VDC:
Subtask 26-13-00-710-057-A
D. Do the test as given in the Para. 3.A.
5. Close-up
Subtask 26-13-00-860-053-A
A. Put the aircraft back to its initial configuration.
[Rev.8 from Aug 2018] 2026.04.04 04:27:17 UTC
"WTRUIB" 2025