Smiths Aerospace
Electronic Systems – Malvern
DOC NO.0134ED
MAINTENANCE MANUAL SUPPLEMENT
BOEING B737-100/200/300/400/500
28-41-04
E. Test
Procedure
(1) Measure the empty tank resistances (Fig. 502).
(a) Set the TEST FUNCTION switch on the test unit to INSULATION.
(b) Set the battery switch to ON.
(c) Turn the METER ADJUST knob until the meter is at its maximum value.
(d) Set the INS TEST POINTS switch to LO-Z/HI-Z.
(e) Read the total resistance for the tank units.
1) Make sure the resistance shown on the test unit is more than 250 megohms.
(f) Set the INS TEST POINTS switch to each of the SHLD or GND positions.
1) Make sure that each resistance shown on the test unit is more than the applicable
minimum resistance:
SWITCH SETTING
MINIMUM RESISTANCE
SH/HI-Z
1
Megohm
SH/LO-Z
1
Megohm
GND/HI-Z
10
Megohm
GND/LO-Z
10
Megohm
GND/SH
10
Megohm
(g) Disconnect the UNSHIELDED lead of the test harness from the INSTULATION LO-Z
receptacle on the test unit.
(h) Connect the COMP wire bundle to the INSULATION LO-Z receptacle.
(i) Set the INS TEST POINTS switch to LO-Z/HI-Z.
(j) Read the resistance of the compensator.
1) Make sure the resistance on the test unit is more than 2000 megohms.
(2) Do this task: Fuel Summation Unit installation or V-Ref/Totalizer installation as applicable
(AMM 28-41-81/401).
(3) Verify that capacitance trimmers are set per paragraph 4.A.5.
(4) Measure the empty tank capacitances (Fig. 503).
(a) Set the TEST FUNCTION switch to CAP BRIDGE.
(b) Turn the D.F. CONTROL knob counterclockwise until it stops.
(c) Disconnect the COAXIAL wire bundle of the test harness from the INSULATION HI-Z
receptacle on the test unit.
(d) Connect the COAXIAL sire bundle to the HI-Z COAX receptacle.
(e) Disconnect the COMP wire bundle from the INSTULATION LO-Z receptacle.
(f) Install a shorting cap on the COMP wire bundle.
(g) Remove the shorting plug from the UNSHIELDED wire bundle.
(h) Connect the UNSHIELDED wire bundle to the LO-Z TANK receptacle.
CONFIG
4.3
Page 512
April 19/02
Airplanes with Smiths 2307 Model Fuel Quantity Indicators
with TSU
(BARFIELD SYSTEM TESTER)
EFFECTIVITY
