Electrical Adjustment - Sony TA-FB720R Service Manual

Bias Adjustment
NOTE:
1. Perform the adjustment after the unit has warmed up sufficiently.
2. Perform the bias adjustment if the power transistor has been
replaced.
Procedure:
1. Rotate fully the bias adjusting semi-fixed resistors (RV500,
RV600) to the MIN position (counterclockwise).
2. Connect a digital voltmeter to the CN500 and CN600.
1 pin
CN500 (L-CH)
+
CN600(R-CH)
+
3. Set the slide regulator to 0V, and press the U button (ON) on
the set.
4. Raise gradually the slide regulator voltage up to the rated voltage.
5. At this time, confirm that the SP relay is turned on (it will click).
6. Adjust the RV500 and RV600 so that a reading of digital
voltmeter is 10 ± 0.1 mV.
7. Return the slidack to 0 V, and press the U button (OFF) on the
set.
Adjustment Location :
[MAIN BOARD] – COMPONENT SIDE –
+
DIGITAL
VOLTMETER
SECTION 2

ELECTRICAL ADJUSTMENT

3 pin
–
–
1
3
CN500 (L-CH)
RV500
Bias (L-CH)
RV600
Bias (R-CH)
CN600 (R-CH)
1
3
+
DIGITAL
VOLTMETER
– 4 –