Amc CVT3030 int paa

Page 1

AMCTM CVT3030 / CVT2030

TECH NOTES
POWER AMPLIFIER ADJUSTMENTS

Important Notes Before Making Adjustments:

1,
2.
3.
4. Unit must be preheated for at least 5 minutes.

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Make sure the primary voltage is set properly (110V - 220V)

Set the "PHONES/NORMAL/DIRECT" switch (on CVT3030 only) to the "PHONES"
position, which mutes the amplifier.

Turn VR502 fully counterclockwise and VR503 fully clockwise.

. Center Voltage Adjustment

Connect a D.C. voltmeter between point A (the junction between the drain of 0508 and
R517) and point 8* (the junction between the drain of 0509 and R519)

Adjust VR501 for a voltmeter reading of 0 volts, +/- 5 volts D.C.

Repeat the above procedures for other channel.

. Bias Current Adjustment

Connect a D.C. voltmeter between point 61* (the plate of tube V502) and point D (the
B+ supply).

Adjust VR502 for a voltmeter reading of 6 volts D.C.

Connect a D.C. voltmeter between point 62* (the plate of tube V501) and point D (the
B+ supply).

Adjust VR503 for a voltmeter reading of 6 volts D.C.

Repeat the above procedures for other channel.

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