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MAIN AMPLIFIER ALIGNMENT
IMPORTANT NOTES:
1) Before adjusting, remove input signal and load, and set Speaker
Impedance switch to 8 ohms. (Reset to 4 ohms when finished.)
2) These adjustments are always necessary after repair to main
amplifier.
3) After repair, it is recommended to use current limiter (40-80W
lightbulb) in series with AC mains line, for initial turn-on.
A. CENTER VOLTAGE ADJUSTMENT
1. Connect DVM across L channel (R channel) output terminals.
2. Turn on, and adjust VR-401 (VR-402) for reading of 0V ± 30 mVDC.
B. IDLE CURRENT ADJUSTMENT
1. Remove solder short across R-471 and R-472.
2. Connect DVM across R-471.
3. Turn on and adjust VR-403 for reading of 28 mV ± 2 mVDC.
4. Repeat, using R-472, adjust VR-404.
C. FINAL ADJUSTMENT
1. Leave power on minimum 5 minutes.
2. Repeat center voltage and idle current adjustments.
3. When finished, replace solder short across R-471 and R-472.
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