Figure 4. Zero crossover waveform.

TB 9-6625-2050-24

(9) Adjust oscilloscope and range calibrator controls to superimpose waveforms as

shown in figure 4, using procedure in (a) through (d) below.

(a) Establish a horizontal grid line as dc average of test point A4TP4 (fig. 2) by

setting range calibrator FUNCTION switch to STANDBY.

(b) Position CH 1 trace on the line.

(d) Press oscilloscope X10 MAG button to activate.

Figure 4. Zero crossover waveform.

(10) Adjust A4R76 (fig. 2) until zero crossover lags the square wave 150 s (R).

(11) Repeat (3) above.

(12) Position A4R46 (fig. 2) to its mechanical center position.

(13) Adjust A4R32 (fig. 2) until multimeter indicates 0 0.2 mV dc (R).

(14) Set range calibrator FUNCTION switch to CALIBRATE and TI range

to 1 mW.

(15) Adjust CAL ADJ until multimeter indicates 1,000 +1 mV dc.

(16) Adjust A4R35 (fig. 2) until TI meter indicates full scale (R).

(17) Set range calibrator to STANDBY.

(18) Set RANGE switch to 3 W and press and hold ZERO switch. Adjust A4R42

(fig. 2) until multimeter indicates 0 mV dc (R). Release ZERO switch.

(19) Set TI RANGE switch to 1 mW.

(20) Set range calibrator FUNCTION switch to CALIBRATE.

(21) Press and hold ZERO switch. Adjust A4R46 (fig. 2) until multimeter indicates

961 mV dc (R). Release ZERO switch.