Krell S-300i schematic

thanks! i have to repair this krell s300i Amplifiers,the noise is very high.But the circuits of this machine are all chip mounted components, and there is no way to start without a circuit diagram.
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For S-300i, I beleive the issue is mainly with the power amp modules. I bought 2 old S-300i. They have repairs to the small SMD transistors on the power section.

https://www.diyaudio.com/community/...n-and-any-possible-ways-to-improve-it.357208/

The capacitors used are not of high quality ones as well. Btw, if you are replacing the power filtering capacitors, replace them of the same 4800uF values. If you use a value that's too big, it will cause the power switch to trip (it has a solenoid breaker). The amp will also show ! (Indicating an error) on the LCD display.

Took me a long long time to figure it out.
 
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This machine is directly connected to the rear stage without any noise, only the front stage produces noise, so the problem must be on the front stage. Both channels have noise, probably in the front stage signal input, power rectification, and other parts, but without a circuit diagram, there is no way to start.
 
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