AMCTM CVT3030 / CVT2030
TECH NOTES
POWER AMPLIFIER ADJUSTMENTS
Important Notes Before Making Adjustments:
1. Make sure the primary voltage is set properly (110V - 220V)
2. Set the "PHONES/NORMAL/DIRECT" switch (on CVT3030 only) to the "PHONES"
position, which mutes the amplifier.
3. Turn VR502 fully counter-clockwise and VR503 fully clockwise.
4. Unit must be pre-heated for at least 5 minutes.
A. Center Voltage Adjustment
1. Connect a D.C. voltmeter between point A* (the junction between the drain of Q508 and
R517) and point B* (the junction between the drain of Q509 and R519)
2. Adjust VR501 for a voltmeter reading of 0 volts, +/- 5 volts D.C.
3. Repeat the above procedures for other channel.
B. Bias Current Adjustment
1. Connect a D.C. voltmeter between point C1* (the plate of tube V502) and point D* (the
B+ supply).
2. Adjust VR502 for a voltmeter reading of 6 volts D.C.
3. Connect a D.C. voltmeter between point C2* (the plate of tube V501) and point D* (the
B+ supply).
4. Adjust VR503 for a voltmeter reading of 6 volts D.C.
5. Repeat the above procedures for other channel.
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