Re: Crown Amp DC300A - One channel distirted, other good.
Crown DC300A Series II schematic, service manual. It looks like yours?
Overall- there's no electrolytics in the signal path, only two in the protection circuit 25uF 15V NP (per ch) and one for 5V DC offset power for both channels C6 100uF, which I would check.
For a quick check if things are reasonable, I would look at +/-10VDC power for the op-amps, check the idling bias current 0.34V across 5.6R driver stage and the op-amp should have around 1.35V at its output.
It's strange to have no bias current trimpot but input offset and output offset trimpots. I think transistors were hand selected and it's a tight design.
This means changing transistors could give bias current (heat) too high or an offset problem. For now, I would just take some voltage measurements to see what is off center.
Crown DC300A Series II schematic, service manual. It looks like yours?
Overall- there's no electrolytics in the signal path, only two in the protection circuit 25uF 15V NP (per ch) and one for 5V DC offset power for both channels C6 100uF, which I would check.
For a quick check if things are reasonable, I would look at +/-10VDC power for the op-amps, check the idling bias current 0.34V across 5.6R driver stage and the op-amp should have around 1.35V at its output.
It's strange to have no bias current trimpot but input offset and output offset trimpots. I think transistors were hand selected and it's a tight design.
This means changing transistors could give bias current (heat) too high or an offset problem. For now, I would just take some voltage measurements to see what is off center.
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