Sony service manual XM-SD22X Section Electrical Adjustment, Bias Adjustment

XM-SD22X

SECTION 3

ELECTRICAL ADJUSTMENT

Bias Adjustment

Note : In Bias Adjustment, adjust RV103 if any of Q108 through

Q113 are replaced. Adjust RV203 if any of Q208 through

Q213 are replaced.

Condition : This adjustment should be performed about one minute after the remote mode is turned on at a room tempera- ture of about 25°C.

Setting :

B+, REM terminal

set

Stabilized

Power supply

GND terminal

Procedure :

1.Turn the variable resistors RV103 (L-CH) and RV203 (R-CH) full clockwise as seen from the component side to minimize the bias current.

2.The input signal is to be no signal.

3.Apply the voltage to the B+ and REM terminals from the stabi- lized power supply and gradually increase it up to 12.0 V while checking for any unusual current.

4.Adjust each of RV103 (L-CH) and RV203 (R-CH) so that the power current of the stabilized power supply is increased in steps of 700 mA (total of 1.4 A).

5.After adjustment, check that the power current is at 1.65 to 2.05 A.

Adjustment Location : Main board (component side)

— MAIN BOARD (CONDUCTOR SIDE) —

RV103	RV203
BIAS ADJUSTMENT	BIAS ADJUSTMENT
(L-CH)	(R-CH)

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