201-299, 401-499, Aug 01/05 CES
4. Fault Isolation
_______________
**ON A/C 001-049, 051-061, 101-105, 201-203,
A. Procedure
NOTE : Where applicable, to show the difference between the left and
____ right wing installations, the FINs given in this procedure are written as follows:
- the left wing, no parenthesis, FIN
- the right wing, in parenthesis, (FIN).
(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 L(R) QTY PROBE 22QT1(2) 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 L(R) QTY PROBE 22QT1(2) 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 to the tank wall connector 4040VC1(2)-A and the shorting plug 4043VC-A(4044VC-A) (Ref. AMM TASK 28-42-43-000-008).
1 Disconnect the:
_
- tank wall connector 4039VC1(2)-A
- shorting plug 4041VC-A(4042VC-A).
(c) Do a visual inspection and electrical tests of the aircraft wiring (Ref. AWM 28-42-11) ((Ref. AWM 28-42-10)) and (Ref. AWM 28-42-13) ((Ref. AWM 28-42-12)) between the FQIC rack connector 3QT-A and the tank wall connector 4040VC1-A(4040VC2-A) as follows:
NOTE : Each capacitive fuel probe is supplied with an alternating
____ current drive, of 30 volts at 30 kilo-hertz, 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 4043VC-A (4044VC-A). The connector is adjacent to and below its related tank wall connector. In the connector:
「一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一1R EFF : 001-049, 051-099, 101-149, 151-199, ∞∞28-42-00∞∞∞∞∞∞∞∞∞∞Page 253
201-299, 401-499, Aug 01/05 CES
- 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 4040VC1(2)-A. Diodes located in the terminal housing of the fuel probe half wave rectify the output signal. The negative going, dc current signal (in proportion to the capacitance value/fuel height from the fuel probe) is routed directly from the tank wall connector 4040VC1(2)-A 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 8D(2J), 1C(6J) and 15D(15K)
- 92VU shelf receptacle 210VC (214VC) and connector 210VC-A(214VC-A)
- receptacle 1970VC (1521VC) and connector 1970VC-A(1521VC-A)
- receptacle (2973VC) and connector (2973VC-A) (right wing only)
- receptacle 7155VC(7110VC) and connector 7155VC-A(7110VC-A)
- pressure seal feedthrough 4017VP(4016VP)
- shorting plug 4043VC-A(4044VC-A) and receptacle 4043VC(4044VC)
- connector 4040VC1(2)-A, pins R, <J and P
- adjacent and related connecting wires.
2 Electrical Tests
_ Do a continuity test (Ref. ESPM 20-52-21) and a test for a short circuit (Ref. ESPM 20-52-22) of the wires that follow (Ref. AWM 28-42-11) ((Ref. AWM 28-42-10)):
- FQIC rack connector 3QT-A, pin 8D(2J) to connector 4040VC1(2)-A, pin R (probe 2 signal)
- FQIC rack connector 3QT-A, pin 1C(6J) to connector 4040VC1(2)-A, pin <J (common drive return)
- FQIC rack connector 3QT-A, pin 15D(15K) to connector 4040VC1(2)-A, pin P (common drive). 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2(130)
