W DOC AIRBUS | TSM A320F

Failure of the Diode Module Related to the GCU 1

TASK 24-20-00-810-959-A
Failure of the Diode Module Related to the GCU 1

1. Possible Causes
  • GCU-1 [1XU1]
  • DIODE MODULE (2420VD)
  • wiring
  • BTC-1 [11XU1]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
ASM 242202
AMM 24-22-34-000-001
Removal of the GCU-1(2)
AMM 24-22-34-400-001
Installation of the GCU-1(2)
AMM 24-22-55-000-001
Removal of the Contactors
AMM 24-22-55-400-002
Installation of the Contactors
AMM 24-41-00-740-002
Operational Check of the GAPCU via the CFDS
3. Fault Confirmation
Subtask 24-20-00-740-112-A ** ON A/C NOT FOR ALL
A. Test
   (1) Do the BITE test of the GAPCU AMM 24-41-00-740-002.
     (a) If the BITE test gives the message TEST FAILED:
  • do the trouble shooting given in Para 4.A.
     (b) If the BITE test gives the message TEST PASSED:
  • stop the trouble shooting.
4. Fault Isolation
Subtask 24-20-00-810-232-A ** ON A/C NOT FOR ALL
A. If the BITE test gives the message TEST FAILED:
  • push the line key adjacent to the TEST FAILED message.
   (1) If the maintenance message GCU1 (1XU1)/DIODE MODULE (2420VD) comes into view associated with the fault code 174 (PRR SSR/DIODE keyword):
     (a) If the fault continues:
  • Replace the DIODE MODULE (2420VD).
   (2) If the maintenance message GCU1 (1XU1)/DIODE MODULE (2420VD) comes into view associated with the fault code 273 (PRR SSR/DIODE keyword):
     (a) If the fault continues:
  • Do a check and repair the wiring between the GCU 1 and the GLC 1 auxiliary control relay (4XU1) ASM 242202 for a short to 28VDC between:
    . Pin AB/10J of the GCU 1 and pin A/C3 of the ELEC/GEN 1 pushbutton switch (3XU1)
    . Pin A/C1 of the ELEC/GEN 1 pushbutton switch and pin A/A of the function relay (20XU)
    . Pin A/1 of the function relay and pin A/X1 of the GLC 1 auxiliary control relay.
     (b) If the fault continues:
  • Do the "BTC LOCKOUT FAILURE" trouble shooting procedure given in paragraph 4.B.
     (c) If the fault continues:
  • Replace the DIODE MODULE (2420VD).
Subtask 24-20-00-810-233-A ** ON A/C NOT FOR ALL
B. Do the BITE test of the GAPCU AMM 24-41-00-740-002:
   (1) If the BITE test gives the message GCU 1 (1XU1):
   (2) If the BITE test gives the message TEST PASSED:
  • Do a check of the wiring for a short to ground between pin B/29 of the BTC 1 and pin AA/4C of the GCU 1 ASM 242202.
     (a) If there is a short to ground:
  • Repair or replace as necessary.
     (b) If there is no short to ground:
  • Do a check of the coil return wiring for a short to ground between pin B/5 of the BTC 1 and pin AA/9A of the GCU 1 ASM 242202.
       1 If there is a short to ground:
  • Repair or replace as necessary.
       2 If there is no short to ground:
  • Do a check of the BTC 1 auxiliary status-contact between pin B/29 and pin B/27 (normally open) ASM 242202.
         a If there is continuity:
         b If there is no continuity:
Subtask 24-20-00-740-113-A ** ON A/C NOT FOR ALL
C. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:26:27 UTC
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