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 fused connector 4041VC-A (4042VC-A). The fused connector is adjacent to and below its related tank wall connector. In the fused connector:
 - 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 through a fuse. 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/fuel height from the fuel probe) is routed directly from the tank wall connector 4039VC1(2)-A to the FQIC rack connector.
 (6) Use a multimeter to do a check for continuity, of the related in line fuse (Ref. ASM 28-42/05) ((Ref. ASM 28-42/06)) between the pins K and

 N.

 (7) If the continuity test shows:

 (a) The fuse has continuity (serviceable), install the serviceable fused connector and continue with step (8).

 (b) The fuse is open circuit (first time unserviceable):

 1 Replace the fused connector 4041VC-A(4042VC-A) with a
_
 serviceable item.

 2 Do the test given in Para. 3.B.
_
 (c) The fuse is open circuit (second time unserviceable):
 1 Continue with step (8), only replace the fused connector
_ 4041VC-A (4042VC-A) when the cause of the short circuit has been identified and corrected.
 (8) Get access to the tank wall connector 4039VC1(2)-A and the fused connector 4041VC-A(4042VC-A) (Ref. AMM TASK 28-42-43-000-008).

 (a) Disconnect the:
 - tank wall connector 4039VC1(2)-A

 - fused connector 4041VC-A(4042VC-A).

 (9) Remove the FQIC 3QT (Ref. AMM TASK 28-42-34-000-001).

 「一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一1R EFF : 001-049, 051-099, 101-149, 151-199, ∞∞28-42-00∞∞∞∞∞∞∞∞∞∞Page A274
 201-299, 401-499, Aug 01/05 CES

 (10) Do a visual inspection and electrical tests of the aircraft wiring (Ref. AWM 28-42-05) ((Ref. AWM 28-42-04)) and (Ref. AWM 28-42-09) ( (Ref. AWM 28-42-08)) between the FQIC rack connector 3QT-A and the tank wall connector 4039VC1-A(4039VC2-A) as follows:

 (a) 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 4K(4E), 7K(3D) and 13H(13B)

 - 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)

 - fused connector 4041VC-A(4042VC-A) and receptacle 4041VC(4042VC)

 - connector 4039VC1(2)-A, pins <R, Z and Y

 - adjacent and related connecting wires.

 (b) 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 28-42-09) ((Ref. AWM 28-42-08)):

 - FQIC rack connector 3QT-A, pin 4K(4E) to connector 4039VC1(2)-A, pin <R (probe 11 signal)

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

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

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

 (d) Connect the:

 - fused connector 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).

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

 (f) Do the test given in Para. 3.B.

 (11) 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).

 「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 A275
　
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