Smiths Aerospace
Electronic Systems – Malvern
DOC NO.0134ED
MAINTENANCE MANUAL SUPPLEMENT
BOEING B737-100/200/300/400/500
28-41-04
TOTAL FUEL QUANTITY/VREF INDICATOR INOPERATIVE – Remove indicator, disconnect electrical
plug, and check for 115 volt AC power between Pin 7 and Pin 4 of plug. (AMM 28-41-04/401)
IF -
Replace total fuel quantity/VREF indicator
and check operation
(REF 28-41-04/401).
Check for break in indicator power cable
between splice inside P2-1 module in center
instrument panel and indicator connector
plug. Repair or replace cable.
Remove power to VREF Totalizer and
reapply. Monitor if display blanks after 15
seconds of normal operation. IF -
OK
OK
Check wiring at plug
connector and correct as
necessary per wiring
diagram.
Determine if voltage
exists on Pins 3 & 9,
3 & 10, 3 & 15.
IF -
Determine cause of signal not
being present and repair.
OK
NOT OK
VREF Totalizer Inoperative
Figure 110
Page 124
April 19/02
Airplanes with Smiths 2307 Model Fuel Quantity
Indicators with TSU
EFFECTIVITY