(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 4039VC1(2)-A and the shorting plug 4041VC-A(4042VC-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 28-42-05) (Ref. AWM 28-42-04) between the FQIC rack connector 3QT-A and the tank wall connector 4039VC1-A(4039VC2-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 4041VC-A (4042VC-A). The connector is adjacent to and below its related tank wall connector. In the connector:
 - the drive wire divides to supply each of its related fuel probes, in parallel

 - the drive return wire also divides to connect to each of

 its related fuel probes, in parallel. All of the discrete drive and drive return wires then go to the tank wall connector 4039VC1(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/permittivity of the fuel because this sensor is normally always covered with fuel) is routed directly from the tank wall connector 4039VC1(2)-A to the FQIC rack connector. Four wires connect the density section of the cadensicon to the tank wall connector 4039VC1(2). These four wires
 「一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一1 EFF : 001-049, 051-061, 101-105, 201-203, ∞∞28-42-00∞∞∞∞∞∞∞∞∞∞Page 220
 Aug 01/05R CES

 are also routed directly from the tank wall connector 4039VC1(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 8K(4D), 7K(3D), 13H(13B), 10G(4A), 9G(3A), 11F(10A) and 8F(7A)

 - 92VU shelf receptacle 214VC (210VC) and connector 214VC-A(210VC-A)

 - receptacle 1521VC (1970VC) and connector 1521VC-A(1970VC-A)

 - receptacle 2973VC and connector 2973VC-A (left wing only)

 - receptacle 7107VC(7154VC) and connector 7107VC-A(7154VC-A)

 - pressure seal feedthrough 4015VP(4018VP)

 - shorting plug 4041VC-A(4042VC-A) and receptacle 4041VC(4042VC)

 - connector 4039VC1(2)-A, pins <Z, GG, AA, H, J, L and K

 - 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 28-42-05) (Ref. AWM 28-42-04)):
 - FQIC rack connector 3QT-A, pin 8K(4D) to connector 4039VC1(2)-A, pin <Z (permittivity signal)

 - FQIC rack connector 3QT-A, pin 7K(3D) to connector 4039VC1(2)-A, pin GG (common drive return)

 - FQIC rack connector 3QT-A, pin 13H(13B) to connector 4039VC1(2)-A, pin AA (common drive)

 - FQIC rack connector 3QT-A, pin 10G(4A) to connector 4039VC1(2)-A, pin H (density signal)

 - FQIC rack connector 3QT-A, pin 9G(3A) to connector 4039VC1(2)-A, pin J (density signal return)

 - FQIC rack connector 3QT-A, pin 11F(10A) to connector 4039VC1(2)-A, pin L (density supply/drive)

 - FQIC rack connector 3QT-A, pin 8F(7A) to connector 4039VC1(2)-A, pin K (density supply/drive return).

 (d) Repair all the unserviceable wiring and connectors (Ref. ESPM 20-00-00).

 (e) Connect the:

 - shorting plug 4041VC-A(4042VC-A) to the receptacle 4041VC(4042VC) (Ref. AMM TASK 28-42-43-400-008)

 - tank wall connector 4039VC1-A(4039VC2-A) to the receptacle 4039VC1(4039VC2).

 (f) Install the initial FQIC 3QT (Ref. AMM TASK 28-42-34-400-001).

 「一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一1 EFF : 001-049, 051-061, 101-105, 201-203, ∞∞28-42-00∞∞∞∞∞∞∞∞∞∞Page 221
 Aug 01/05R CES

 (g) Do the test given in Para. 3.B.
 (4) If the fault continues, drain and open the tank to the air (Ref. AMM TASK 28-10-00-910-001) and (Ref. AMM TASK 28-10-00-910-002).
　
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