Sharp SG-290H - Page 8

SG-290H/HB
©
ADJUSTMENT OF TUNER CIRCUIT
FM iF/RF ADJUSTMENT
@ Set the function selector switch at FM position.
@ Set the signal generator to produce a signal of 1kHz, 40kHz dev.,
FM modulated.
@ 8Sefore the adjustment, loosen the core of T203 by about 1mm.
FRE- DIAL
QUEN- | POINTER
cY SETTING
AD-
JUST-
MENT
TEST
STAGE REMARKS
IF (Connect instruments as shown in Fig.10—1.}
Adjust for best “IF”
T101 Curve
High
frequency
10.7MHz
Adjust for best “S”
T203 Curve
tion
Repeat steps 1 and 2 until no further improvement can be made.
RF (Connect instruments as shown in Fig.10—4.)
Lowest
li
87.35MHZ | ecuency
L103
Band
coverage
Highest
108.30MHz frequency
TC103
Adjust for
output.
maximal
L101,
L102
Tune to
90MHz 90MHz
Tracking r 3
Tune to
VO6MHz | so6MHz
TC101
TC102
Repeat steps 4, 5 and 6, 7 until no further improvement can be made.
VCO FREQUENCY ADJUSTMENT
© Connect instruments as shown in Fig.10—5.
© Set the function selector switch at FM stereo position.
@
Set
the
signal
generator
to
produce
a
signal
of
1kHz,
40kHz
dev.,
FM modulated (mono signal).
DIAL
POINTER
SETTING
ADJUST-
FREQUENCY MENT
REMARKS
* Tune to
98MHz
Adjust for 19 kHz +
25 Hz
98MHz at 60dB VR301
+ After tuning the set to 98 MHz, perform the adjustment with the FM signal
generator unmodulated.
FM Signal
generator
FM External
Antenna Socket Frequency counter
TP301@
TP301 @)
Ground
Figure 10-5 VCO FREQUENCY ADJUSTMENT
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Figure 10-6 ADJUSTMENT POINTS (DECK)
-10-
Oscilloscope
Sweep
generator
FM External
Antenna
Socket
TP201 @
Ground
Figure 10-1 FM IF ADJUSTMENT
10.7 MHz
10.7 MHz
Figure 10-2 ;
FM “IF”? CURVE Figure 10-3
FM “S” CURVE
Electronic
FM Signal voltmeter
generator
FM External Antenna
Socket
TP201(1)
TP201@)
Ground
Figure 10-4 FM RF ADJUSTMENT
AM FM
EX ANT. SOCKET
%,
Cc
Teel
*G
L205 L204
aed ®
Tc203 | |TCIO3 TCloz TCIOI
TC201 KX} TC202
L202(A) L202(B)
Figure 10-7 ADJUSTMENT POINTS (TUNER)