XM-7527 - Sony Car Audio Service Manual (repair manual). Page 8

8

• Perform adjustments in the  HI-VOLTAGE  mode.

1 Adjustment point

Semi-fixed resistors VR101, VR201 of amplifier board.

2 Precautions on adjustments
1. Set the RCA input terminal to open.
2. Apply a voltage of 14.4V between the +12V terminal, REMOTE

terminal, and GND terminal.

3. Rotate the above semi-fixed resistors completely in the coun-

terclockwise direction while observing the component side.

4. Check that the voltage at the adjustment point becomes 0 mV

in step 2.

5. Fine adjustments may be required according to the characteris-

tics of the MOS-FET used.

• When adjusting the idling current

Rotating the semi-fixed resistor in the clockwise direction:
In creases the idling current
Rotating the semi-fixed resistor in the counterclockwise direc tion:
Decreases the idling current

* Take note that rotating excessively in the clockwise direction

will increase the idling current suddenly.

3 Approximate adjustment values

Adjust as follows so that the following voltages become
0.4 to 0.5 mV .

 L channel  :
Voltage between TP101 and TP102: Use VR101 of the ampli-
fier board
 R channel  :
Voltage between TP201 and TP202: Use VR201 of the ampli-
fier board

Digital voltmeter

TP101(L-CH)
TP201(R-CH)

TP102(L-CH)
TP202(R-CH)

IDLING

(R-CH) VR201

VR101 (L-CH) 

TP202

TP201

TP102

TP101