SA-500 Rt channel distortion- Please help

rdaufan

Auburn Tiger Fan
I recently purchased this receiver and cleaned outside and inside. The volume knob was producing quite a bit of static, so I removed all knobs and cleaned the contacts. This took care of the issue.

Sounds great except for one thing. The rt channel is apparently producing a buzz/distortion that I can hear...almost sounds like the tweeter on the speaker is blown, but I have eliminated this as an issue. At higher volumes, the more the sound is distorted...like when you overpower a speaker.

Can anyone point me in the rt direction on what to check next? Maybe my volume knob contacts need more cleaning? Thanks!
 
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I cleaned the volume pot again and did not resolve the issue. When listening through headphones, there is no distortion whatsoever. Does this sound like a bad power resistor?
 
Check the center point voltages on the amps, read all 4 collectors which are connected to the metal transistor cases of the four 2sd130 output transistors.

One should be exactly HALF of the other's voltage on each channel... It is adjustable.

Otherwise it's a transistor or resistor.
 
Sounds great except for one thing. The rt channel is apparently producing a buzz/distortion that I can hear...almost sounds like the tweeter on the speaker is blown, but I have eliminated this as an issue. At higher volumes, the more the sound is distorted...like when you overpower a speaker.

Can anyone point me in the rt direction on what to check next? Maybe my volume knob contacts need more cleaning? Thanks!

I'd look for a bad cap or two on the pre amp board. It would be a good idea to recap the entire integrated as they are way past their life span.
 
Turned out to be a bad transistor in the power amp circuit. Got it back and sounds really good - very tube-like !
 
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