DOC AIRBUS | TSM A320FFailure of the RS422 Electrical Connection between the GPCU and the GCU 1
TASK 24-41-00-810-804-A
Failure of the RS422 Electrical Connection between the GPCU and the GCU 1
1. Possible Causes
A. Referenced Information
3. Fault Confirmation
Subtask 24-41-00-710-055-A ** ON A/C NOT FOR ALL 4. Fault Isolation
Subtask 24-41-00-810-053-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:26:53 UTC
Failure of the RS422 Electrical Connection between the GPCU and the GCU 1
1. Possible Causes
wiring between the circuit breaker (2XU1) and the GCU 1 - C/B-ELEC/GCU/1 [2XU1]
- wiring of the RS422 bus
- GCU-1 [1XU1]
- GPCU [1XG]
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 24-41-00-740-004 | Operational Check of the GPCU via the CFDS |
| ASM 244102 | |
| 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) |
Subtask 24-41-00-710-055-A ** ON A/C NOT FOR ALL 4. Fault Isolation
Subtask 24-41-00-810-053-A ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message NO DATA FROM GCU 1:
Subtask 24-41-00-710-056-A ** ON A/C NOT FOR ALL - on the circuit breaker panel 122VU, do a check of the status of the circuit breaker (2XU1).
- close it.
- do a check for 28VDC on the pin A/1D of the GCU 1.
- do a check of the
wiring between the circuit breaker (2XU1) and the GCU 1 ASM 242202.
- repair the wiring.
- replace the C/B-ELEC/GCU/1 [2XU1] .
- do a check of the wiring of the RS422 bus between respectively the GCU 1 pins B/14C, B/14D and the GPCU pins A/13C, A/14C ASM 244102.
- repair the above wiring.
- replace the GCU-1 [1XU1] AMM 24-22-34-000-001 and AMM 24-22-34-400-001 .
- replace the GPCU [1XG] AMM 24-41-34-000-001 and AMM 24-41-34-400-001.
B. Do the test given in Para. 3.