TM 11-5840-217-34-1
f. Measure and record the resistance across the cw and ccw terminals of R1407 with the Wheatstone bridge.
g. Select the larger of the two resistance readings in d and f above and record as RA.
Compute for RB as follows:
RB = 0. 016 RA
h. Carefully set the bridge for RB (, above). Connect the Wheatstone bridge between the ccw and SL (slider)
terminals of R1407. (Do not press the "read" buttons on the bridge at this time. )
i. Rotate the range coupling until the RANGE counter reads 300 meters. Slightly loosen the clamps that hold R1407.
j. Press the read buttons on the Wheatstone bridge and rotate R1407 for a null while holding the RANGE counter at
300 meters with the coupling. Tighten the clamps that hold R1407.
Caution: Do not rotate R1407 more than 45' in either direction during this procedure.
k. Press the read buttons on the Wheatstone bridge and recheck for a null by turning the range coupling. If the
reading is not 300 meters + 5 meters, repeat the steps in i and i above.
l Reconnect the lead to the cw terminal of R1407.
7-9. ELEVATION RESOLVER AND COUNTER ALINEMENT
a. Connect the oscilloscope input to EL RSVR SINE TP1402 and GRD TP1406.
b. Rotate the RANGE handwheel to its maximum cw position.
c. Rotate the ELEVATION handwheel to zero elevation (ELEVATION counter reads 0).
d. Loosen the four mounting screws that secure resolver B1202 to the elevation assembly.
e. Rotate the body of resolver B1202 to obtain a null on the oscilloscope. Tighten the four resolver mounting screws.
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Note: If the null cannot be obtained without rotating the resolver more than
in either direction, check the mechanical
alinement of elevation resolver B1202 to ELEVATION counter MlZO1.
f. After obtaining the null point, rotate the ELEVATION handwheel to further reduce the null. The null should not
exceed 100 millivolts peak-to-peak, with an ELEVATION counter reading of 0 + one-fourth mil.
g. If the counter reading is greater than 0 + one-fourth mil, repeat the steps in d, e, and f above.
Note: Use only the 400-hertz component of the waveform when observing the null.
7-10. ELEVATION RESOLVER DRIVER AMPLIFIER ADJUSTMENTS
a. With the ELEVATION and RANGE handwheels, set the ELEVATION counter to 0 and the RANGE counter to 14,
000 meters.
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