Vco Frequency Adjustment - Sharp GF-320A Service Manual

FM IF/RF ADJUSTMENT
FM mono
SIGNAL
400 Hz, 30%. FM modulated.
GENERATOR
TEST
STAGE
1
IF
Detection
Repeat steps 1 and 2 until no further improvement can
be made.
Band
coverage
109 MHz
5
Repeat steps 4 and 5 until no further improvement can
6
be made.
7 88 MHz
108 MHz
9 Repeat steps 7 and 8 until no further improvement can
be made.

VCO FREQUENCY ADJUSTMENT

SIGNAL
400 Hz, 30%. FM modulated
GENERATOR
FM mono position
98 MHz
98 MHz at
60 dB
AD-
JUST- REMARKS
1. Using a minus
driver, turn
the core of
clockwise
before taking
it out of the
frequency bobbin.
2. Adjust for
curve.
Adjust for best
"S" curve.
frequency
TC2
Highest maximal output.
frequency
Adjust for
maximal
output.
108 MHz
FM stereo position (unmodulated)
Adjust for
38.00 kHz + 100 Hz.
10.7 MHz
Figure 7-l FM IF
Figure 7-2 IF CURVE
FM Signal
Rod Antenna
Generator
Dummy
(See Figure 7-6)
Figure 74 FM RF
FM Signal
Generator
Rod Antenna
Dummy
Figure 7-5 VCO FREQUENCY
Figure 7-6 FM DUMMY
Oscilloscope
Figure 7-3 FM S CURVE
Electronic
External
Voltmeter
Speaker
Unit
Electronic
To Telescopic Rod Antenna
To Chassis GND