Friday, November 20, 2015

SONY XM-2002GTW CAR AMPLIFIER BIAS ADJUSTMENT AND POWER SUPPLY CIRCUIT

SONY XM-2002GTW 

CAR AMPLIFIER 

BIAS ADJUSTMENT AND POWER SUPPLY CIRCUIT 

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 temperature of about 25°C.
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 stabilized 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.

Power Connection Wires
If you have the factory original or some other car audio unit without a remote output on the amplifier, connect the remote input terminal (REMOTE) to the accessory power supply. In High Level Input Connection, car audio unit can also be activated without need for REMOTE connection. However, this function is not guaranteed for all car units

As the Monaural Amplifier for a Subwoofer
For details on the settings of switches and controls, refer to “Location and Function of Controls.”
Note
If you wish to use a subwoofer as a monaural speaker, connect the speaker as illustrated above. The output signals to the subwoofer will be the combination of the both right and left output signals.

Caution
# Before making any connections, disconnect the ground terminal of the car battery to avoid short circuits.
# Be sure to use speakers with an adequate power rating. If you use small capacity speakers, they may be damaged.
# Do not connect the # terminal of the speaker system to the car chassis, and do not connect the # terminal of the right speaker with that of the left speaker.
# This is a phase-inverted Amplifier.
# Install the input and output cords away from the power supply wire as running them close together can generate some interference noise.
# This unit is a high powered amplifier. Therefore, it may not perform to its full potential if used with the speaker cords supplied with the car.
# If your car is equipped with a computer system for navigation or some other purpose, do not remove the ground wire from the car battery. If you disconnect the wire, the computer memory may be erased. To avoid short circuits when making connections,  disconnect the +12 V power supply wire until all the other wires have been connected.
CIRCUIT DIAGRAM 
CLICK ON THE IMAGE TO ZOOM IN