Hey all. I have this Marantz model 1030 amplifier with some problems.
Problem 1: Left channel has extreme distortion under any kind of load. If you crank the bass control, it distorts to hell and gone.
Problem 2: When attempting to set the bias voltage for the left channel, it's ENTIRELY too high. The service manual states 7.5mVDC at idle. It won't go below 130mV. The right channel has no distortion and I was able to successfully set it's bias current to 7.5mV.
I think what's going on here is that something is pulling the bias voltage way up on the left channel and when you load that channel down, the high bias voltage causes the transistor to be driven into distortion.
What might be pulling the bias voltage up? Will this kill the transistors in short order?
TIA.
Service Manual: https://cdn.badcaps-static.com/pdfs/...739e9f0da8.pdf
Problem 1: Left channel has extreme distortion under any kind of load. If you crank the bass control, it distorts to hell and gone.
Problem 2: When attempting to set the bias voltage for the left channel, it's ENTIRELY too high. The service manual states 7.5mVDC at idle. It won't go below 130mV. The right channel has no distortion and I was able to successfully set it's bias current to 7.5mV.
I think what's going on here is that something is pulling the bias voltage way up on the left channel and when you load that channel down, the high bias voltage causes the transistor to be driven into distortion.
What might be pulling the bias voltage up? Will this kill the transistors in short order?
TIA.
Service Manual: https://cdn.badcaps-static.com/pdfs/...739e9f0da8.pdf
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