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Tracking and Sensitivity
Precaution: No adjustment
is required. The tracking and sensitivity has been adjusted properly and completely at the
factory. If any special reason occasioned, take the following procedures very carefully:
AC VTVM
RF Generator
Oscilloscope
Fig. 22
Low Frequency
1.
Connect an RF generator to the antenna terminals on the rear panel through a dummy antenna.
2.
Set the RF generator to 88 MHz, a modulation of 1 kHz and a deviation of 75 kHz, to provide an input of 2 nV.
3.
Connect
a VTVM
and an oscilloscope to the Rec. Out Jacks on the rear panel.
4.
Set the dial pointer to 88 MHz.
5.
Adjust three coils L103, L102 and L101 in the tuning gang to maximize the output.
High Frequency
6.
Set the RF generator to 108 MHz, a modulation of 1 kHz and a deviation of 75 kHz, to provide an input of 2 uV.
7.
Set the dial pointer to 108 MHz.
8.
Adjust the FM trimmers TC5, TC3 and TC1 in the tuning gang to maximize the output.
9.
Repeat these high and low frequency adjustments alternately until maximum sensitivity is obtained.
Multiplex and Stereo Separation
Oscilloscope
RF Generator
Fig. 23
Multiplex
1.
Set a stereo
signal generator
as follows:
Modulation
frequency
1 kHz, Deviation
pilot 7.5 kHz, Main and Sub.
67.5 kHz. Connect its output to an RF generator.
Connect the RF generator to the antenna terminals through
a dummy antenna.
Connect a VTVM, an oscilloscope and a distortion meter to the Rec. Out Jacks.
Set the RF generator to 98 MHz and an output of 1 mV.
Set the dial pointer to 98 MHz.
Connect a frequency counter to Tab No. 136.
Switch off the pilot signal of the stereo modulator.
Adjust R304 so that the frequency counter indicates 76 kHz (+ 0.05 kHz).
COT
Oe Ol Beco
Stereo Separation
9.
Switch the selector of the stereo modulator to left channel modulation.
10.
Adjust R318 so that the output of the right channel is minimized.
11.
Switch the selector of the modulator to right channel modulation.
12.
Adjust R318 so that the output of the left channel is minimized.
13.
Set R318 to average, if the separation of right and left are different.
Note: Keep the "MONO"
push button out during this adjustment procedure of stereo separation.
JR-S81
240
No. 2431
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