TB 9-6625-2171-24
(5) Set VOR 1020HZ switch to ON. Press and hold VOR 30VAR pushbutton.
Measuring receiver will indicate an amplitude modulation between 5 and 15 percent.
Release VOR 30VAR pushbutton.
(6) Press and hold VOR 30VAR pushbutton. Measure distortion.
Measuring
receiver will indicate less than 10 percent. Release VOR 30VAR pushbutton.
(7) Set VOR 1020HZ switch to OFF.
(8) Measure distortion. Measuring receiver will indicate less than 5 percent.
(10) Press and hold VOR 30VAR and 30REF pushbuttons. Measure distortion. If
measuring receiver does not indicate less than 3 percent, perform b (2) through (4) below.
(11) Press and hold VOR 30VAR and 30REF pushbuttons. Measure modulation
rate. Measuring receiver will indicate between 9959.004 and 9960.996 Hz. Release VOR
30VAR and 30REF pushbuttons.
(12) Short A6J12 (fig. 3) to ground. Measuring receiver will indicate between 29.997
and 30.003 Hz.
(13) Set VOR 1020HZ switch to ON.
(14) Press and hold VOR 30VAR pushbutton. Measuring receiver will indicate
between 994.5 and 1045.5 Hz. Release VOR 30VAR pushbutton and set VOR 1020HZ
switch to OFF.
b. Adjustments
(1) Adjust A6R105 (fig. 3) for indication of 30 percent on measuring receiver (R).
(2) Connect oscilloscope to A6J13 (fig. 3). Connect measuring receiver to A6J12 and
chassis ground.
(3) Press VOR 30VAR and 30REF pushbuttons and measure distortion. Adjust
A6R80 (fig. 3) for minimum distortion while adjusting A6R57 (fig. 3) for a symmetrical
(4) Disconnect equipment setup and connect measuring receiver power sensor
module to TI J3. Measure distortion. If distortion is still high, adjust A5L5 and A5L6 (fig.
4) for minimum distortion (R).
NOTE
15 a (4) above VOR RF level.
17. VOR 9960 FM Deviation
a. Performance Check
(1) Connect oscilloscope channel 1 to TI A6J12 (fig. 3).
(2) Adjust oscilloscope controls for an 8 division sinewave display presentation at
vertical setting of 200 mV/div, uncal, and horizontal setting of 100 Ps/div.
