**ON A/C ALL

 TASK 28-46-00-810-820
 LEFT HI LVL Indicator Lamp Does Not Come On When TEST Switch Set To LTS
 WARNING : OBEY THE FUEL SAFETY PROCEDURES.
_______
 1. Possible Causes
_______________
 - lamp

 - Panel Assy-Refuel (800VU)

 - C/B-FUEL/HI/LVL/SPLY (1QJ)

 - aircraft wiring

 - SWITCH-TEST/HIGH/LTS (2QJ) (part of 800VU)

 - diode module (4002VD) (part of 800VU)

 - INDICATOR-HI LVL/LEFT (3QJ) (part of 800VU)

 - Panel Assy-Refuel (800VU) internal wiring

 2. Job Set-up Information
______________________
 A. Fixtures, Tools, Test and Support Equipment
 -------------------------------------------------------------------------------REFERENCE QTY DESIGNATION -------------------------------------------------------------------------------

No specific multimeter
 B. Referenced Information
 -------------------------------------------------------------------------------REFERENCE DESIGNATION -------------------------------------------------------------------------------
AMM 28-25-55-000-001 Removal of the Refuel Panel 800VU
 AMM 28-25-55-400-001 Installation of the Refuel Panel 800VU
 AMM 28-46-00-710-001 Test of the Tank High Level Sensing System
 AWM 28-46-01
 AWM 28-46-02
 AWM 28-46-03

 3. Fault Confirmation
__________________
 A. Do up to and including Para. 3.A. of the Operational Test of the HI LVL Lights (Ref. AMM TASK 28-46-00-710-001).
 NOTE : The OPEN DEFUEL/XFR lamp (21QU) should also come on during the
____
 time the TEST switch is held at LTS.
 The OPEN DEFUEL/XFR indicator lamp (21QU):

 - 28VDC supply is from a different C/B
 「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 : ALL ∞∞28-46-00∞∞∞∞∞∞∞∞∞∞Page A251
 May 01/05R CES

 - switched ground/earth uses the same contacts of SWITCH-TEST/HIGH/LTS (2QJ).
 4. Fault Isolation
_______________
 A. If the LEFT HI LVL indicator lamp only does not come on and the others do:
 - replace the LEFT HI LVL indicator lamp bulb.
 OR
 If at least one HI LVL indicator lamp comes on but others do not:
 - replace the related lamps.
 (1) If the fault continues or if none of the Panel Assy-Refuel (800VU) HI LVL indicator lamps come on:
 (a) Remove the Panel Assy-Refuel (800VU) (Ref. AMM TASK 28-25-55-000-001).

 (b) Do a check (Ref. AWM 28-46-01), and (Ref. AWM 28-46-02) with a multimeter to see if:

 1 28VDC is available at the aircraft connector 4023VC pin <C.
_
 2 A ground/earth is available at the aircraft connector 4024VC
_
 pin <J.

 (2) If 28VDC and the ground/earth is available at the aircraft connectors as specified above:
 - replace the Panel Assy-Refuel (800VU), (Ref. AMM TASK 28-25-55-000-001), and (Ref. AMM TASK 28-25-55-400-001).
 NOTE : If due to airline operational conditions it is not possible to
____ replace the Panel Assy-Refuel (800VU) and internal Trouble-shooting is required, go to Step (8).
 (3) If 28VDC is not available in Step (1)(b)1_:

 - check/reset/replace the C/B-FUEL/HI/LVL/SPLY (1QJ) at 121VU212.

 (4) Do the test given in Para. 3.A.

 (5) If the fault continues do a check (Ref. AWM 28-46-01), and (Ref. AWM 28-46-02) of the aircraft wiring:

 - between the C/B-FUEL/HI/LVL/SPLY (1QJ) and the refuel panel connector 4023VC pin <C

 - between the DC1 ground point and the refuel panel connector 4024VC pin <J.

 (6) Repair all the unserviceable wiring and connectors.

 (7) Do the test given in Para. 3.A.

 「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 : ALL ∞∞28-46-00∞∞∞∞∞∞∞∞∞∞Page A252
 May 01/05R CES

 (8) Panel Assy-Refuel (800VU) Internal Trouble-shooting, (Ref. AWM 28-46-02), and (Ref. AWM 28-46-03):
 (a) Check/replace the SWITCH-TEST/HIGH/LTS (2QJ) (part of 800VU).

 (b) Check/replace the diode between terminals 3 and 4 of diode module (4002VD) (part of 800VU).

 (c) Check/replace the INDICATOR-HI LVL/LEFT (3QJ) (part of 800VU).
　
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