BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
(d) 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.
(e)
Make sure the TANK CAP PF thumbwheels are set to 40.2
picofarads (pf) with a tolerance of |1.2 pf.
(f)
Release the PRESS TO MEASURE switch.
(g)
Set the battery switch to OFF.
(h)
Disconnect the COMP wire from the system test unit.
(i)
Install a shorting plug on the COMP wire.
(j)
Remove the shorting plug from the UNSHIELDED wire.
(k)
Connect the UNSHIELDED wire to the LO-Z TANK receptacle on the system test unit.
(l)
Set the battery switch to ON.
(m)
Push the PRESS TO MEASURE switch and hold it.
(n)
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.
(o)
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
(p)
If the thumbwheels are set to a value out of the applicable capacitance range, do the system test.
S 825-021-003
(2) Adjust the capacitance trimmer.
(a)
Get access to the capacitance trimmers on the pilot's instrument panel, P1, above the hand microphone receptacle.
(b)
Turn the applicable capacitance trimmer until the test unit display shows the applicable value: TANK CAPACITANCE (pf)
No. 1 and 2 506.6
Center 180.2 1) Turn the trimmer with a screwdriver. 2) Remove the screwdriver. 3) Let the value on the test unit meter become stable. 4) Continue this procedure until you get the correct
capacitance.
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AIRPLANES WITH ANALOG FUEL QUANTITY ú 28-41-00
INDICATORS ú CONFIG 3 ú 01A Page 508 (BARFIELD SYSTEM TESTER) ú Nov 12/99
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
(c) Release the PRESS TO MEASURE switch.
S 825-022-003
(3) Adjust the test unit to give the capacitances equivalent to a full fuel tank (Fig. 503).
(a)
Set the battery switch on the test unit to OFF.
(b)
Disconnect the test harness from the test unit.
(c)
Set the FUNCTION switch to CAP BRIDGE.
(d)
Set the TANK CAP PF thumbwheels to 41.4.
NOTE: This is the capacitance value added to the empty
____ tank capacitance by the test unit to simulate a full tank.
(e)
Set the battery switch to ON.
(f)
Push the COMP CAL switch and hold it.
