DOC AIRBUS | TSM A320FLoss of LPTC Torque Motor Control through the Channel B on Engine 1
TASK 73-29-00-810-893-A
Loss of LPTC 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 73-29-00-710-202-A ** ON A/C NOT FOR ALL
Subtask 73-29-00-810-185-A ** ON A/C NOT FOR ALL
[Rev.8 from Aug 2018]
2026.04.04 04:41:06 UTC
Loss of LPTC 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 73-21-10-000-002 | Removal of the Hydromechanical Unit (HMU) |
| AMM 73-21-10-400-001 | Installation of the Hydromechanical Unit (HMU) |
| AMM 73-21-10-400-002 | Installation of the Hydromechanical Unit (HMU) |
| AMM 73-21-50-000-007 | Removal of J8 Harness |
| AMM 73-21-50-000-041 | Removal of the HJ8 Harness for SAC Engines |
| AMM 73-21-50-400-007 | Installation of the J8 Harness |
| AMM 73-21-50-400-041 | Installation of the HJ8 Harness for SAC Engines |
| 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) |
| ASM 732518 | |
| AMM 73-29-00-710-040 | Operational Test of the FADEC on the ground (with Engine Motoring) |
Subtask 73-29-00-710-202-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.
Subtask 73-29-00-810-185-A ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message J8, HMU(LPTCTM), ECU:
Subtask 73-29-00-810-185-B ** ON A/C NOT FOR ALL - do a check for open or short to ground at pins J8/19, 38, 39 of the harness J8 between the ECU (4000KS) and the LPT torque-motor current in the HMU, ASM 732518.
- repair the above wiring.
- disconnect the harness J8 from the ECU and do a check of the ECU cable resistance between:
. pins 19 and 38 (17 to 23 Ohms)
. pins 19 and 39 (> 10 Megohms)
. pin 19 and the ground (> 10 Megohms)
- 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 19 and 38 (17 to 23 Ohms)
. pins 19 and 39 (> 10 Megohms)
. pin 19 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.
A. If the test gives the maintenance message J8, HMU(LPTCTM), ECU:
Subtask 73-29-00-710-203-A ** ON A/C NOT FOR ALL - do a check for open or short to ground at pins J8/19, 38, 39 of the harness J8 between the ECU (4000KS) and the LPT torque-motor current in the HMU, ASM 732518.
- repair the above wiring.
- disconnect the harness J8 from the ECU and do a check of the ECU cable resistance between:
. pins 19 and 38 (17 to 23 Ohms)
. pins 19 and 39 (> 10 Megohms)
. pin 19 and the ground (> 10 Megohms)
- 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 19 and 38 (17 to 23 Ohms)
. pins 19 and 39 (> 10 Megohms)
. pin 19 and the ground (> 10 Megohms).
- replace the harness J8 , AMM 73-21-50-000-041 and AMM 73-21-50-400-041.
- replace the HMU-1 [4000KC1] AMM 73-21-10-000-002 and AMM 73-21-10-400-002.
B. Do the test given in Para. 3.A.(1).