Sony ST-A35L - Page 9

VCO Adjustment
A) Regular Method
Setting:
STEREO switch: OFF
Procedure:
FM rf signal
generator
FM antenna
terminal
Carrier
frequency:
98MHz
Modulation:
400Hz,
40kHz
deviation
(100%)
Output
level:
1mV
(60aB)
1. Tune the set to 98MHz
2.
Adjust
RT302
for
76kHz
+
100Hz
on
the
counter.
wr frequency counter
ie
B) Simple Method
Procedure:
1. Tune the set to the FM stereo broadcasting signal.
2.
Turn
RT302
clockwise
or
counterclockwise
and
memorize
the
lighting-up
range
of
the
stereo
lamp.
3. Secure RT302 at the center of the lighting-up
range of both turns as shown below.
center of lighting-up ranges
ligh ting-up range
=a
oon
~
~— =a
|
ST-A3SL
ST-A3SL
CAL TONE Level Adjustment
Setting:
CAL TONE switch: ON
Procedure:
OUTPUT
Adjust RT601 for 0.35—0.44V (—6 +1dB) reading on
the VI'VM.
RT6071
A, TT
RT202
RT301
Signal Indicator Level Adjustment
Setting:
STEREO switch: OFF
Procedure:
FM rf signal
generator
Modulation:
Output level:
Tune the set to 98MHz and adjust RT202 so that
all signal elements light up. (See figure below.)
FM Muting Level Adjustment
Setting:
STEREO switch: ON (muting ON)
Procedure:
FM
rf
signal
VOM
generator
(AC
range)
FM antenna
terminal
FM antenna OUTPUT
Carrier
frequency:
98MHz
terminal
400Hz, 40kHz deviation Carrier frequency: 98MHz
(100%) Modulation: 400Hz, 40kHz deviation
316uV (50dB) (100%)
Output level: 7.9nV (18dB)
1. Tune the set to 98MHz.
2. Turn RT201 and stop it just when the VOM
light up “aor :
indication suddenly decreases.
SIGNAL STRENGTH
3. Receive a signal stronger than the muting level.
Confirm that the ACUTE SERVO LOCK lamp
(green) lights up. (See figure below.)
22724 | 422227318272
a San
RT201
LOCKED
FM Stereo Separation Adjustment
FM stereo
signal generator
output channel
VTVM
connection
VTVM
reading (dB)
Setting:
STEREO switch: ON (muting ON)
Procedure:
Adjust
RT301 for
FM rf stereo minimum
signal
—
reading.
generator
Adjust
RT301 for
minimum
reading.
FM antenna OUTPUT
terminal
Carrier frequency: 98MHz L-CH Stereo separation: () -
Output level: 1mV (60dB) R-CH Stereo separation: ~ ©
Modulation:
Audio (400Hz): 16.25kHz deviation (45%)
Pilot (19kHz): 7.5kHz deviation (10%)
Sub-channel: 16.25kHz deviation (45%)
The separations of both channels should be
equal.
—10—