Sharp GF-320H Serviceanleitung Seite 13

FM IF/RF ADJUSTMENT
FM mono
SWITCH
POSITION
400 Hz, 30%, FM modulated
SIGNAL
GENERATOR
FRE_
TEST
QUENCY
STEP STAGE
High
10.7 MHz
frequency
2 Detection
RepeatstepsI and 2 until nc further improvement c an be
3
made.
87.3 MHz Lowest
4 Band
frequency
coverage
108.3 MHz Highest
5
frequency
Repeatsteps4 and 5 until nofurther improvement c an be
6
made.
Tracking 88 MHz
7
108 MHz
8
Repeat s teps7 and 8 untii no further improvement c anbe
9
made.
VCO FREQUENCY ADJUSTMENT
400 Hz, 30%, FM modulated
SIGNAL
GENERATOR
DIAL
POINTER
FREQUENCY
SETTING
FM mono position
98 MHz
98 MHz at
60 dB
DIAL
REMARKS
POINTER JUST-
SETTING MENT
1. Using a minus
driver, turn the
core of T 2
counterclock-
wise before
taking it out of
the bobbin.
2. Adjust for best
curve.
Adjust for best
"S" curve.
Adjust for
maximal output.
TC2
Adjust for
88 MHz
maximal output.
108 MHz TCI
(mono signal)
AD-
REMARKS
JUST-
MENT
FM stereo position {unmodulated)
Adjust for 38.00 kHz
VRI
± 100 HZ.
10.7 MHz
FM Sweep
Generator
iCl
O Pin
0.01
GND
Figure 13
10.7 MHz
13—2 IF CURVE
Figure
FM Signal
Rod Antenna
Generator
GND
Dummy
(See Figure 13—6)
Figure
FM Signal
Rod Antenna
Generator
GND
Dummy
(See Figure 13—6}
Figure 13—5
RI
Z = 75 ohms<
Z = 50 ohms<
Z: Output impedance Of signal generator
Figure 13—6
—13
GF-320H/E
Oscilloscope
IC3
O Pin
Unit
GND
FM iF
—1
10.7 MHz
Figure 13—3 S CURVE
Electronic
External
Voltmeter
Spea ker
Terminal
4 ohms
unit
GND
13—4 FM RF
Electronic
Voltmeter
@ Pin
1000 pF
unit
1 kohm
VCO FREQUENCY
To Telescopic rod antenna
To chassis GND
RI = 37.5 ohms
R2 = 75 ohms
= 50 ohms
R2 = 50 ohms
FM DUMMY
o
Frequency
Counter