Read Sony ST-SA50ES Service Manual online
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SECTION 4
ELECTRICAL ADJUSTMENTS
Precautions in Repairing
If the front end unit fails, it is difficult to repair the inner circuits, so
replace the entire front end unit.
replace the entire front end unit.
•
Standard Setting of FM Stereo RF Signal Generator.
FM SECTION
0dB = 1µV
STEREO STANDARD SIGNAL
MONAURAL
STANDARD SIGNAL
Carrier frequency : 98MHz
Modulation
Modulation
: Audio 1kHz
Main channel (L+R) : 33.75kHz
deviation
Sub channel (L–R)
: 33.75kHz
deviation
Pilot
: 7.5kHz
Deviation
Carrier frequency:98MHz
Modulation
Modulation
:Audio 1kHz
75kHz
deviation
deviation
FM Discriminator ADJUSTMENT
(NULL and MONO Distortion Adjustment)
(NULL and MONO Distortion Adjustment)
Setting:
IF BAND : WIDE
IF BAND : WIDE
Procedure:
1. Tune the set to 98 MHz.
2. Adjust T252 for 0V reading on the VTVM.
1. Tune the set to 98 MHz.
2. Adjust T252 for 0V reading on the VTVM.
................... NULL
3. Adjust T253 for a minimum reading on the distortion meter.
................... MONO Distortion (THD)
4. Repeat the adjustments of 2 and 3 several times.
Note : When replacing the ceramic filter, perform this alignment.
set
FM RF Stereo
signal generator
signal generator
1kHz
highpass
filter
highpass
filter
distortion meter
FM ANTENNA (75
Ω
)
LINE OUT
set
FM RF Stereo
signal generator
signal generator
1kHz
highpass
filter
highpass
filter
distortion meter
FM ANTENNA (75
Ω
)
(at 75
Ω
open)
Modulation : Monaural Standard signal
Output level : 6mV (76dB
Output level : 6mV (76dB
µ
)
LINE OUT
VTVM
(DC range)
(DC range)
TP251
NULL terminal
NULL terminal
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