TM 11 -5840217-34-1
h. Lock the pot and recheck the null.
i. Return S803 to the OPR position; remove the oscilloscope leads and jumper.
7-6. COMPUTING VOLTAGE PHASE AND AMPLITUDE BALANCE ADJUSTMENTS
a. Set the X-Y-RHO switch to CAL.
b. Set COMP VOLT BAL switch S801 to CAL.
c. Connect the oscilloscope to X IN TP803 and GRD TP813.
d. Loosen the locknuts and adjust COMP VOLT AMPL pot R995 and COMP VOLT PHASE pot R997 for a null of less
than 10 millivolts peak-to-peak as observed on the oscilloscope.
e. Tighten the locknuts on R995 and R997 and recheck the null.
f. Return S801 and S803 to the OPR position; remove the oscilloscope leads.
7-7. RANGE POT ALINEMENT
a. Set MAP SCALE switch S1401 to 1:25K.
b. Turn the ELEVATION handwheel so that the ELEVATION counter reads 0.
c. Rotate the RANGE handwheel to its maximum cw position.
d. Loosen the three clamps that secure pot R1402 to the range assembly.
e. Rotate the body of pot R1402 until the RANGE counter reads 18,288 meters. Permissible error is +20 meters.
Caution: When rotating pot R1402, do not exert undue pressure. Loosen the clamps further if R1402 does not turn
freely. If the rear section of R1402 turns without an equal turning of the front section, replace the pot and realine the
f. Tighten the three clamps and secure pot R1402 in place.
7-8. RHO POT ALINEMENT
a. Disconnect the lead attached to the cw terminal of R1407.
b. Turn the plotting board range coupling until the ccw stop on R1407 is reached.
Caution: To prevent damage to the pot, approach the stops on R1407 slowly and do not use force to turn the coupling.
c. Check to see that 1:25K RANGE counter M1401 reads 0 with R1407 at the ccw stop. If not, loosen the three
screws mounting the clamps that hold R1407. Rotate R1407 with the range coupling (while holding the RANGE counter at
0), until the ccw stop coincides with zero range.
d. Connect the Wheatstone bridge across the cw and ccw terminals of R1407. Measure and record the resistance.
e. Turn the plotting board range coupling (observing the caution warning in b above) until the cw stop on R1407 is