4. Fault Isolation
_______________
A. Procedure
NOTE : The Ultracomp 52QT is in the right wing and located between Ribs 2
____
and 3.
(1) Temporarily replace the FQIC 3QT with a serviceable item (Ref. AMM TASK 28-42-34-000-001) and (Ref. AMM TASK 28-42-34-400-001).
NOTE : The step (1) has been included because it is important to make
____ sure that the FQIC is serviceable before you start more steps.
(2) If the message R ULTRACOMP 52QT or R ULTRACOMP 52QT/WRG is not shown:
- complete the installation of the FQIC (3QT) (Ref. AMM TASK 28-42-34-000-001) and (Ref. AMM TASK 28-42-34-400-001).
(3) If the message R ULTRACOMP 52QT or R ULTRACOMP 52QT/WRG is shown:
(a) Remove the temporary installed serviceable FQIC 3QT (Ref. AMM TASK 28-42-34-000-001) and return it to stores.
(b) Get access (Ref. AMM TASK 28-42-43-000-008) to the:
- tank wall connectors 4039VC2-A and 4040VC2-A
- shorting plug 4044VC-A.
1 Disconnect the:
_
- tank wall connectors 4039VC2-A and 4040VC2-A
- shorting plug 4044VC-A.
(c) Do a visual inspection and electrical tests of the aircraft wiring (Ref. AWM 28-42-04), (Ref. AWM 28-42-10) and (Ref. AWM 28-42-12) between the FQIC rack connector 3QT-A and the tank wall connectors 4039VC2-A and 4040VC2-A as follows:
NOTE : Each capacitive fuel probe is supplied with an alternating
____ current drive from the FQIC. The fuel probes in a tank group (harness) share the drive and drive return (two aircraft wires) between the FQIC rack connector and the connector 4044VC-A. The connector 4044VC-A is adjacent to and below its related tank wall connector 4040VC2. In the connector 4044VC-A:
- the drive wire divides to supply each of the related fuel probes, in parallel
- the drive return wire also divides to connect to each of the related fuel probes,in parallel. All of the discrete drive and drive return wires then go to the tank wall connector 4040VC2-A. Diodes located on a circuit card assembly in the ultracomp half wave rectify the output signal. The positive going, dc current signal (in proportion to the
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capacitance value/fuel dielectric) is routed directly from the tank wall connector 4040VC2-A to the FQIC rack connector. The density (Velocity of Sound - VOS)/temperature section of the ultracomp is connected (by two wires) to the tank wall connector 4039VC2 and routed directly to the FQIC rack connector.
1 Visual Inspection
_ Make sure that good lighting is available. Do a visual inspection and look for distortion (bent, pinched or stretched), damage (broken, chafed or cut), discoloration, overheating (burnt, melted or arcing), liquid contamination, loose electrical connection, or incorrect assembly of the items that follow:
- FQIC rack connector 3QT-A, pins 13K, 14K, 3A, 7A and 4D
- 92VU shelf receptacle 210VC and connector 210VC-A
- 92VU shelf receptacle 214VC and connector 214VC-A
- receptacle 1970VC and connector 1970VC-A
- receptacle 1521VC and connector 1521VC-A
- receptacle 2973VC and connector 2973VC-A
- receptacle 7110VC and connector 7110VC-A
- receptacle 7155VC and connector 7154VC-A
- pressure seal feedthrough 4016VP
- pressure seal feedthrough 4018VP
- shorting plug 4044VC-A and receptacle 4044VC-A
- connector 4039VC2-A, pins H, J 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 FUEL 燃油3(57)
