- replace the ECU (4000KS), (Ref. AMM TASK 73-21-60-000-001) and (Ref. AMM TASK 73-21-60-400-001).
(b) If the resistance values are out of the specified limits:
- disconnect the harnesses J7 and 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).
1 If the resistance values are in the specified limits:
_
- replace the defective harness J7, (Ref. AMM TASK 73-21-50-000-040) and (Ref. AMM TASK 73-21-50-400-040) or the defective harness J8, (Ref. AMM TASK 73-21-50-000-041) and (Ref. AMM TASK 73-21-50-400-041).
2 If the resistance values are out of the specified limits:
_
- replace the Hydromechanical Unit (HMU), (Ref. AMM TASK 73-21-10-000-002) and (Ref. AMM TASK 73-21-10-400-002).
B. Do the test given in Para. 3.A.(1).
F 『 EEFF : ALL E ∞∞73-29-00∞∞∞∞∞∞∞∞∞∞Page 296
E E Feb 01/05 ERE
ECES
F 『
E C F M E
E E
E 56 E
E E
TASK 73-29-00-810-859
Loss of the RAC SB Torque Motor Control through the Two Channels on Engine 2
1. Possible Causes
_______________
- ECU (4000KS)
- harness J7
- harness J8
- Hydromechanical Unit (HMU)
2. Job Set-up Information
______________________
A. Referenced Information
-------------------------------------------------------------------------------REFERENCE DESIGNATION -------------------------------------------------------------------------------
AMM 73-21-10-000-002 Removal of the Hydromechanical Unit (HMU) AMM 73-21-10-400-002 Installation of the Hydromechanical Unit (HMU) AMM 73-21-50-000-040 Removal of the HJ7 Harness AMM 73-21-50-000-041 Removal of the HJ8 Harness AMM 73-21-50-400-040 Installation of the HJ7 Harness AMM 73-21-50-400-041 Installation of the HJ8 Harness AMM 73-21-60-000-001 Removal of the Electronic Control Unit (ECU)(4000KS) AMM 73-21-60-400-001 Installation of the Electronic Control Unit
(ECU)(4000KS) AMM 73-29-00-710-040 Operational Test of the FADEC on the ground (with Engine Motoring) ASM 73-25/18
3. Fault Confirmation
__________________
A. Test
(1) Do the operational test of the FADEC 2A and 2B on the ground (with engine motoring) (Ref. AMM TASK 73-29-00-710-040).
NOTE : If post SB 75-029, fault message must be ignored: no trouble
____
shooting is necessary.
4. Fault Isolation
_______________
A. If the test gives the maintenance messages J7, HMU(RAC TM), ECU + J8, HMU(RAC TM), ECU:
- do a check for open or short to ground at pins J7/20, 39, 40 and J8/20, 39, 40 of the harnesses J7 and J8 between the ECU (4000KS) and the RACC torque motor in the HMU, (Ref. ASM 73-25/18).
(1) If one of these wirings is not correct:
- repair the defective harness J7 or J8.
F 『 EEFF : ALL E ∞∞73-29-00∞∞∞∞∞∞∞∞∞∞Page 297
E E May 01/05 ERE ECES
F 『
E C F M E
E E
E 56 E E E (2) If these wirings are correct:
- disconnect the harnesses J7 and J8 from the ECU and do a check of the ECU cable resistance between: . pins 20 and 40 (17 to 23 Ohms) . pins 20 and 39 (> 10 Megohms) . pin 20 and the ground (> 10 Megohms).
(a) If the resistance values are in the specified limits:
- replace the ECU (4000KS), (Ref. AMM TASK 73-21-60-000-001) and (Ref. AMM TASK 73-21-60-400-001).
(b) If the resistance values are out of the specified limits:
- disconnect the harnesses J7 and 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).
1 If the resistance values are in the specified limits:
_
- replace the defective harness J7, (Ref. AMM TASK 73-21-50-000-040) and (Ref. AMM TASK 73-21-50-400-040) or the defective harness J8, (Ref. AMM TASK 73-21-50-000-041) and (Ref. AMM TASK 73-21-50-400-041).
2 If the resistance values are out of the specified limits:
_
- replace the Hydromechanical Unit (HMU), (Ref. AMM TASK 73-21-10-000-002) and (Ref. AMM TASK 73-21-10-400-002).
B. Do the test given in Para. 3.A.(1).
F 『 EEFF : ALL E ∞∞73-29-00∞∞∞∞∞∞∞∞∞∞Page 298
E E May 01/05 ERE
ECES TASK 73-29-00-810-860
