Smiths Aerospace
Electronic Systems – Malvern
DOC NO.0134ED
MAINTENANCE MANUAL SUPPLEMENT
BOEING B737-100/200/300/400/500
28-41-04
Measure resistance from
Tank Lo-Z to Hi-Z at the
indicator connector
(AMM 28-41-04/501)
Clear FQI errors and
confirm error persists
Repair A/C harness
(WDM 28-41-01)
<50 megohm
>50 megohm
Remove TSU harness from
Tank wall. connector
Remove bussing plug and measure
resistance across individual tank units
<50megohm
>50 megohm
Replace TSU
(AMM 28-41-04/401)
Drain sump to remove
water from tank
(AMM 28-23-00/301)
Return to service
Error cleared
Error persists
Remove master indicator.
(AMM 28-41-04/401)
Disconnect A/C Harness from TSU
Measure resistance from Tank
Lo-Z to Hi-Z at tank wall
Repair/Replace applicable tank
unit/harness
(AMM 28-41-81/401)
<50megohm
>50 megohm
Repair/Replace harness
(AMM 28-41-44/401)
Operational Test
(AMM 28-41-04/501)
Err 6: Tank Unit Leakage
Figure 107
Page 120
April 19/02
Airplanes with Smiths 2307 Model Fuel Quantity
Indicators with TSU
EFFECTIVITY