changed the op amp with a new one i found, turned the bias on booth channels fully down, the noise is gone, only the upper half of one channel is missing in the waveform.
checked the gate drive, i have positive and negative signal on the fets...so maybe some fets are damaged..
mosfets all ok, transitors and diodes are all ok...i dont now anymore......
the mosfets for positive and for negativ become a signal, but only the lower half of the waveform is produced.
The input is allready the upper half noisy.
Back to the beginning. The input is allready noisy at the first cap at the rca jacket. If i use the other channel, its clean.
If i connect the load to the other channel, it has the same effect. Upper half missing, and allready at the cap from rca noisy input.
the mosfets for positive and for negativ become a signal, but only the lower half of the waveform is produced.
The input is allready the upper half noisy.
Back to the beginning. The input is allready noisy at the first cap at the rca jacket. If i use the other channel, its clean.
If i connect the load to the other channel, it has the same effect. Upper half missing, and allready at the cap from rca noisy input.
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FOUND IT........... Removed the muting transistor... now i have a clean signal.
Changed with new transistor, same again. But the problem comes from the mute circuit...
Changed with new transistor, same again. But the problem comes from the mute circuit...
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Goodmorning everyone !! I am trying to repair an audio system x ion 280.2 amplifier! in theory the amplifier has no faults but the audio does not come out in speaker! The mosfets are all good but i have not bias voltage on the power mosfets.Can you give me some diagrams or some advice ?? thank you very much good job everyone