(e)
Connect the COMP wire bundle to the INSULATION LO-Z receptacle.
(f)
Set the INS TEST POINTS switch to LO-Z/HI-Z.
(g)
Read the resistance of the compensator.
1) Make sure the resistance on the system tester is more than 250 megohms.
(h)
Set the TEST FUNCTION switch to CAP BRIDGE.
(i)
Turn the D.F.CONTROL knob counterclockwise to the 12 o'clock position.
NOTE: Some Barfield testers have a stop at this position,
____ but some testers do not have this stop.
(j)
Disconnect the COAXIAL wire bundle of the test harness from the INSULATION HI-Z receptacle on the test unit.
(k)
Connect the COAXIAL wire bundle to the HI-Z COAX receptacle.
(l)
Disconnect the COMP wire bundle from the INSULATION LO-Z receptacle.
(m)
Install a shorting cap on the COMP wire bundle.
(n)
Remove the shorting plug from the UNSHIELDED wire bundle.
(o)
Connect the UNSHIELDED wire bundle to the LO-Z TANK receptacle.
(p)
Install a shorting cap on the COMP receptacle on the test unit.
S 415-053-003
(2)
Do this task: Fuel Summation Unit Installation (AMM 28-41-81/401).
S 825-054-003
(3)
Set the capacitance trimmer.
NOTE: This step sets the airplane wiring to a standard
____ capacitance value of 16 pf. This will make it easier to find problems with the capacitances of the equipment in the fuel tank.
(a)
Get access to the bussing plug installed on the spar for the applicable tank (Fig. 501).
(b)
Disconnect the electrical connector from the bussing plug.
NOTE: Do not disconnect the bussing plug from the
____
receptacle installed on the spar.
(c)
Get access to the capacitance trimmers on the pilot's instrument panel, P1, above the hand microphone receptacle.
(d)
Set the TANK CAP PF thumbwheels to 16.0.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. AIRPLANES WITH SIMMONDS DIGITAL FUEL ú
28-41-02 QUANTITY INDICATORS ú CONFIG 3
ú 02 Page 518 (BARFIELD SYSTEM TESTER) ú Nov 12/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
(e)
Push the PRESS TO MEASURE switch and hold it.
(f)
Turn the applicable capacitance trimmer with a screwdriver until the test unit shows a minimum value on the meter.
(g)
Release the PRESS TO MEASURE switch.
(h)
Connect the electrical connector to the bussing plug installed on the spar.
S 975-040-003
(4) Measure the empty tank capacitances.
(a)
Push the PRESS TO MEASURE switch on the test unit and hold it.
(b)
Turn the TANK CAP PF thumbwheels until the meter shows the minimum value.
NOTE: If you turn the thumbwheels to a position farther
____ than the correct position, the value increases.
(c) Turn the D.F.CONTROL knob until the meter shows the minimum value.
NOTE: If you turn the knob to a position farther than the
____ correct position, the value increases. The D.F. CONTROL has very little effect for capacitances below approximately 50 pF. The test unit is more sensitive to adjustment of the D.F. CONTROL for larger capacitances.
(d)
Make sure the thumbwheels are set to these capacitance values with the applicable tolerance: ~.......................................................... | TANK | CAPACITANCE (pf) | TOLERANCE (pf) | ............................................................ | No. 1 and 2 | 506.6 | |7.8 | ............................................................ | Center | 180.2 | |2.7 | 2...............…........................….................1
1) If the capacitance is out of the correct range of values, do this task: Tank and Compensator Units Test (AMM 28-41-21/501) to find a bad tank unit or wire harness.
(e)
Release the PRESS TO MEASURE switch.
(f)
Set the battery switch to OFF.
(g)
Disconnect the UNSHIELDED wire bundle from the test unit.
(h)
Install a shorting plug on the UNSHIELDED wire bundle.
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本文链接地址：737-300 400 500 AMM 飞机维护手册 燃油 FUEL 3(103)
