(1) No additional maintenance action is required if the fault is not confirmed.
(2) Repeat the fault isolation procedure if the fault continues.
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TASK 78-31-00-810-822
Thrust-Reverser HCU Pressure-Switch Feedback Disagree on Engine 2
1. Possible Causes
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- PRESS SW-HCU (4102KS)
- harness J5
- harness J6
- thrust reverser harness
- junction box
- ECU (4000KS)
2. Job Set-up Information
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A. Referenced Information
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REFERENCE DESIGNATION
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AMM 71-51-43-000-049 Removal of the ECU (Channel A) to Thrust Reverser Junction Box Harnesses (4213KS) AMM 71-51-43-400-049 Installation of the ECU (Channel A) to Thrust
Reverser Junction Box Harnesses (4213KS) 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 78-31-00-710-042 Operational Test of the Thrust Reverser System AMM 78-31-16-000-041 Removal of the Hydraulic Control Unit Pressure Switch
(4102KS) AMM 78-31-16-400-041 Installation of the Hydraulic Control Unit Pressure Switch (4102KS) ASM 73-25/16
3. Fault Confirmation
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A. Do an operational test of the thrust reverser system (Ref. AMM TASK 78-31-00-710-042).
4. Fault Isolation
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A. This fault message is generated if there is a disagreement between channel A and channel B on the HCU pressure switch output signal.
(1) If the test gives the maintenance message TR PR SW, J5/J6, ECU:
- get access to the HCU,
- disconnect the harnesses J5 and J6 from the HCU pressure switch (4102KS),
- install jumper wires between pins 2 and 3 on the harness J5 connector and between pins 4 and 5 on the harness J6 connector,
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- disconnect the harnesses J5 and J6 from the ECU (4000KS) and do a resistance check at each harness connector to the ECU (Ref. ASM 73-25/16) between: . pins 12 and 13 (<5 ohms) . pins 12 and 11 (>10 megohms)
R . pin 12 and the ground (>10 megohms).
(a) If the resistance values are in the specified limits:
- replace the PRESS SW-HCU (4102KS) (Ref. AMM TASK 78-31-16-000-041) and (Ref. AMM TASK 78-31-16-400-041).
(b) If the resistance values are out of the specified limits:
- do a continuity and insulation check of the harnesses between the ECU and the HCU pressure switch,
- repair or replace the defective harness J5 or harness J6 or thrust reverser harness or junction box (Ref. AMM TASK 71-51-43-000-049) and (Ref. AMM TASK 71-51-43-400-049).
(c) If the fault continues:
- replace the ECU (4000KS) (Ref. AMM TASK 73-21-60-000-001) and (Ref. AMM TASK 73-21-60-400-001).
(2) If the test does not give the maintenance message TR PR SW, J5/J6, ECU; this is indicative of an intermittent fault that may be caused by defective electrical contacts in the harnesses and junction box between the ECU and the HCU:
- do a check of the harnesses J5 and J6 and the thrust reverser harnesses and the junction box between the ECU and the HCU for correct condition,
- do a check of the connectors for looseness, bent pins, corrosion or contamination.
(a) If damage is found:
- clean, repair or replace as required (Ref. AMM TASK 71-51-43-000-049) and (Ref. AMM TASK 71-51-43-400-049).
(b) If no damage is found and fault continues while maintenance message is never confirmed during the test:
- replace the PRESS SW-HCU (4102KS) (Ref. AMM TASK 78-31-16-000-041) and (Ref. AMM TASK 78-31-16-400-041).
(c) If the fault continues:
- repair or replace the defective harnesses J5 or J6 or thrust reverser harness (Ref. AMM TASK 71-51-43-000-049) and (Ref. AMM TASK 71-51-43-400-049). 中國航空網 www.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：A320 Trouble Shooting Manual 排故手冊 EXHAUST(17)
