W DOC AIRBUS | TSM A320F

Loss of the Power Supply of the CFDIU

TASK 31-32-00-810-881-A
Loss of the Power Supply of the CFDIU

1. Possible Causes
  • CFDIU [1TW]
  • wiring
  • C/B-CFDS/CFDIU/SPLY [2TW]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 31-32-34-000-001
Removal of the CFDIU
AMM 31-32-34-400-001
Installation of the CFDIU
AWM 313244
3. Fault Confirmation
Subtask 31-32-00-740-206-A
A. Test
Not applicable (see fault isolation).
4. Fault Isolation
Subtask 31-32-00-810-130-A
A. do a check of the status of the circuit breaker (2TW).
   (1) If the circuit breaker (2TW) is closed:
  • do a check for 28VDC between pin AC/3 and pin AC/8 of the CFDIU (1TW) AWM 313244.
     (a) If there is 28VDC:
     (b) If there is no 28VDC:
  • do a check for a ground signal at pin AC/8 of the CFDIU (1TW) AWM 313244.
       1 If there is no ground signal:
  • repair the wiring between CFDIU (1TW) pin AC/8 and the ground terminal AWM 313244.
       2 If there is a ground signal:
  • do a check of the wiring between CFDIU (1TW) pin AC/3 and the circuit breaker (2TW) AWM 313244.
         a If there is no continuity:
  • repair the wiring.
         b If there is continuity:
  • replace the C/B-CFDS/CFDIU/SPLY [2TW]
   (2) If the circuit breaker (2TW) is open:
  • close the circuit breaker.
     (a) If the circuit breaker trips:
       1 If the fault continues:
  • do a check for a short to ground at the wiring between CFDIU (1TW) pin AC/3 and the circuit breaker (2TW) AWM 313244.
         a If there is a short to ground:
  • repair the wiring.
         b If there is no short to ground:
  • replace the circuit breaker (2TW).
     (b) If the circuit breaker (2TW) stays closed and the fault continues:
  • replace the CFDIU [1TW] .
[Rev.8 from Aug 2018] 2026.04.04 04:29:54 UTC
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