Electrical Adjustment - Sony XM-SD22X Instructions De Service

XM-SD22X
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 :
Stabilized
Power supply
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) —
10
SECTION 3

ELECTRICAL ADJUSTMENT

B+, REM terminal
set
GND terminal
RV103
BIAS ADJUSTMENT BIAS ADJUSTMENT
(L-CH)
RV203
(R-CH)