ST-SB920 - Sony Audio Service Manual (repair manual). Page 5

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If the front end unit fails, it is difficult to repair the inner circuits, so
replace the entire front end unit.

Set “IF : WIDE” after the all adjustments.

•

Standard Setting of FM Stereo RF Signal Generator.

Method 1:
1. Set the reception mode to FM.
2. Push the  MENU  button and turn the  TUNING/SELECT  to

indicate “Reception” on the fluorecent display tube, then press
the  ENTER  button.

3. Rotate the  TUNING/SELECT  knob in the clokwise direction.

(Proceeds onto the step 5 when rotated in the counterclokwise
direction.)

4. Turn the  TUNING/SELECT  knob to indicate “ANT ATT :

OFF” on the fluorescent display tube, then press the  ENTER

l

button.

5. Turn the  TUNING/SELECT  knob to indicate “IF : NARROW”

or “IF : WIDE” on the fluorescent display tube, then press the

l

ENTER  button.

When the IF BAND : NARROW is set, “NARROW” is
indicated on the fluorescent display tube.

6. Set WIDE after the operation.

* When set to standby for inputs using the  TUNING/SELECT

l

knob, “SELECT” is indicated on the fluorecent display tube.

Method 2:
After the test modes “2. Display Tube Check and KEY Check mode”
or “3. Entering the Factory Preset”, “IF : NARROW” and “IF :
WIDE” are switched every time pressing RETURN button the IF
BAND : NARROW is set “NARROW” is indicated on the
fluorescent display tube.
Likewise, the mode can be switched between “ANT ATT : ON”
and “ANT ATT : OFF”. When set to ANT ATT : ON, the fluorescent
display tube indicates ANT ATT.

set

FM RF SSG

1kHz
highpass
filter

distortion meter

FM ANTENNA (75

Ω

)

LINE OUT

STEREO STANDARD SIGNAL

MONAURAL

STANDARD SIGNAL

Carrier frequency : 98MHz
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 : Audio 1kHz

75kHz deviation

Setting:
IF BAND : WIDE
ANT ATT : OFF

Procedure:
1. Tune the set to 98 MHz.
2. Adjust IFT252 for 0V reading on the digital voltmeter.

................... NULL

3. Adjust IFT253 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 SSG

1kHz
highpass
filter

distortion meter

FM ANTENNA (75

Ω

)

Modulation : Monaural Standard signal
Output level : 6mV (76dB) (at 75 

Ω

 open)

LINE OUT

Digital Voltmeter
(DC range)

TP251
NULL terminal