Smiths Aerospace
Electronic Systems – Malvern
DOC NO.0134ED
MAINTENANCE MANUAL SUPPLEMENT
BOEING B737-100/200/300/400/500
28-41-04
Remove master indicator.
(AMM 28-41-04/401)
Disconnect A/C Harness from TSU.
Repair fault to ground in
A/C harness
(WDM 28-41-01)
>50 megohm
<50 megohm
Measure resistance from Tank Lo-Z to
GND at the indicator connector.
Clear FQI errors and
confirm error persists
< 5 ohm
>5 ohm
Determine Continuity of Tank Lo-Z line
from indicator connector to tank wall
connector
Repair open Tank Lo-Z line
in A/C harness
(WDM 28-41-01)
1
Repair fault to Hi-Z Shield
in A/C harness
(WDM 28-41-01)
>50 megohm
<50 megohm
Measure resistance from Tank Lo-Z to
Hi-Z Shield at the indicator connector.
Err 4: Tank Lo-Z Line Open or Short
Figure 105 (Sheet 1)
Page 117
April 19/02
Airplanes with Smiths 2307 Model Fuel Quantity
Indicators with TSU
EFFECTIVITY