DOC AIRBUS | TSM A320FLoss of the RAC Torque Motor Control through the Channel B on Engine 1
TASK 73-29-00-810-881-A
Loss of the RAC Torque Motor Control through the Channel B on Engine 1
1. Possible Causes
2. Job Set-up Information
A. Referenced Information
3. Fault Confirmation
Subtask 73-29-00-710-178-A ** ON A/C NOT FOR ALL
Subtask 73-29-00-810-173-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:36:00 UTC
Loss of the RAC Torque Motor Control through the Channel B on Engine 1
1. Possible Causes
2. Job Set-up Information
A. Referenced Information
| REFERENCE | DESIGNATION |
|---|---|
| AMM 73-21-10-000-001 | Removal of the Hydromechanical Unit (HMU) |
| AMM 73-21-10-400-001 | Installation of the Hydromechanical Unit (HMU) |
| AMM 73-21-50-000-007 | Removal of J8 Harness |
| AMM 73-21-50-210-002 | Visual Inspection of the Wiring Harnesses |
| AMM 73-21-50-400-007 | Installation of the J8 Harness |
| AMM 73-21-60-000-001 | Removal of the Electronic Control Unit (ECU) |
| AMM 73-21-60-400-001 | Installation of the Electronic Control Unit (ECU) |
| AMM 73-29-00-710-040 | Operational Test of the FADEC on the ground (with Engine Motoring) |
Subtask 73-29-00-710-178-A ** ON A/C NOT FOR ALL
A. Test
(1) Do the operational test of the FADEC 1B on the ground (with engine motoring) AMM 73-29-00-710-040.
4. Fault Isolation(1) Do the operational test of the FADEC 1B on the ground (with engine motoring) AMM 73-29-00-710-040.
NOTE: If post SB 75-029, fault message must be ignored: no trouble shooting is necessary.
Subtask 73-29-00-810-173-A ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message J8, HMU(RAC TM), ECU:
- Disconnect the J8 harness from the J8 receptacle on the ECU (4000KS). Make sure that the electrical contacts of the J8 receptacle are not bent or have not moved AMM 73-21-50-210-002.
(1) If you find damage:
. pins 20 and 40 (17 to 23 Ohms)
. pins 20 and 39 (> 10 Megohms)
. pin 20 and the ground (> 10 Megohms).
(3) If the resistance values are in the specified limits:
Subtask 73-29-00-710-179-A ** ON A/C NOT FOR ALL - Disconnect the J8 harness from the J8 receptacle on the ECU (4000KS). Make sure that the electrical contacts of the J8 receptacle are not bent or have not moved AMM 73-21-50-210-002.
(1) If you find damage:
- replace the ECU [4000KS] , AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
. pins 20 and 40 (17 to 23 Ohms)
. pins 20 and 39 (> 10 Megohms)
. pin 20 and the ground (> 10 Megohms).
(3) If the resistance values are in the specified limits:
- replace the ECU [4000KS] , AMM 73-21-60-000-001 and AMM 73-21-60-400-001.
- disconnect the harness J8 from the HMU and do a check of the HMU receptacle resistance between:
. pins 20 and 40 (17 to 23 Ohms)
. pins 20 and 39 (> 10 Megohms)
. pin 20 and the ground (> 10 Megohms).
- replace the harness J8 , AMM 73-21-50-000-007 and AMM 73-21-50-400-007.
- replace the HMU-1 [4000KC1] AMM 73-21-10-000-001 and AMM 73-21-10-400-001.
B. Do the test given in Para. 3.A.(1).