Sharp VZ-1600H Serviceanleitung Seite 16

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CIRCUIT ADJUSTMENT (TUNER SECTION)
FM IF/RF ADJUSTMENT Dummy
(See figure 22—6) a
SWITCH
10.7 MHz
Oscillosope
POSITION
FM mono
FM Sweep Generator FM External
aS HATOR 400 Hz, 40 kHz dev., FM modulated. Z , J
GND TP104
DIAL AD-
1. Using a minus
driver, turn
the core of
T202 coun-
1 (F T102 terclockwise
before taking
10.7 MHz} High it out of the
frequen cy bobbin.
2. Adjust for Figure 22—2 FM "IF" CURVE Figure 22—3 FM "S" CURVE
best "IF''
curve.
2 Detection T202 Adjust for best : FM External EV.
"S" curve. FM Signal (See Figure 22-6.) Antenna
Generator __ Dummy EZ
3 Repeat steps 1 and 2 until no further improvement can be
made.
87.35 Lowest L104
Band MHz frequency
GND TP104
Figure 22—4 FM RF
coverage
108.30 Highest Adjust for ~
MHz frequency| TC103 | maximal output.
5 FM Signal FM External'
6
Repeat steps 4 and
5 until no further improvement can be
Ge Antenna
Frequency
made. nerator L TP105 100 kohms Caunter
Adjust for
Tracking Free aie maximal output. (See Figure 22-6) TP106
Figure 22—5 VCO
9 Repeat steps 7 and 8 until no further improvement can
be made. .
VCO FREQUENCY ADJUSTMENT
: R2
SIGNAL 400 Hz, 40 kHz dev., FM modulated
GENERATOR (mono signal)
DIAL
FREQUENCY | POINTER | AUJUST-
SETTING :
FM mono position FM stereo position (unmodulated)
98 MHz at VR301 Adjust for
60 dB 19 kHz + 25 Hz.
RI
RS
To Telescopic Rod Antenna
Z = 50 ohms
R1 = 50 ohms
R2 = 125 ohms
R3 = 150 ohms
Z= 75 ohms
R1 = 75 ohms
R2 = 112.5 ohms
R3 = 150 ohms
To Chassis GND
Z : Output impedance of signal generator
Figure 22—6 FM DUMMY
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