XM-1502SX, XM-1902GX - Sony Car Audio Service Manual (repair manual). Page 8

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Note : In Bias Adjustment, adjust RV105 if any of Q108 through

Q113 are replaced. Adjust RV205 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.

– MAIN BOARD (COMPONENT SIDE) –

RV105

BIAS ADJUSTMENT

(L-CH)

RV205

BIAS ADJUSTMENT

(R-CH)

Procedure :
1. Turn the variable resistors RV105 (L-CH) and RV205 (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 14.4 V while
checking for any unusual current.

4. For the XM-1502SX, adjust each of RV105 (L-CH) and RV205

(R-CH) so that the power current of the stabilized power supply
is increased in steps of 500 mA (total of 1 A). For the XM-
1902GX, adjust each of RV105 (L-CH) and RV205 (R-CH) so
that the power current is increased in steps of 600 mA (total of
1.2 A).

5. After adjustment, check that the power current is at 1.3 to 2.0 A.

Adjustment Location : Main board (component side)

Stabilized 

Power supply

B+, REM terminal

set

GND terminal