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Howdy,
I have a Sunn Beta Lead (head only no speakers with it). It's been sitting in my neighbors garage for years and he said I could have it if I shoveled his snowy driveway. Sweet deal! The amp doesn't work. When I moved it, I could hear something moving around inside. I opened it and found a resistor floating around. You can tell it created a lot of heat because there were burn marks under it and it melted out the solder (the legs didn't break). My issue seems somewhat related to the Drummer4gc post: https://music-electronics-forum.com/...lation-circuit
I am used to building pedals and guitars but not amps. I made sure all caps were drained and started checking pieces with my multimeter. The resistor that fell out was still good, I raised it off the board with some 14g copper wire (used for wall outlets) - someone on another forum said I should to reduce heat against the board.
I don't know what to check anymore. Nothing looks wrong, but when I fixed the resistor and plugged it into my speaker cab, it gave me a load pop and buzzing sound like nothing was coming through. What should I check next? Any ideas? Thanks!
Pictures: https://drive.google.com/drive/folde...Z_?usp=sharing
Note: I have a Klein mm420 and when I try to test bigger caps (3300uf), I get OL. I didn't realize my tool wouldnt be able to test everything. Maybe I should return it and get a better one?
Edit: Someone told me this -
That resistor looks like it feeds a voltage regulator.
Could be a shorted regulator transistor or a short in the DC path.
Would take some testing to determine.
I have a Sunn Beta Lead (head only no speakers with it). It's been sitting in my neighbors garage for years and he said I could have it if I shoveled his snowy driveway. Sweet deal! The amp doesn't work. When I moved it, I could hear something moving around inside. I opened it and found a resistor floating around. You can tell it created a lot of heat because there were burn marks under it and it melted out the solder (the legs didn't break). My issue seems somewhat related to the Drummer4gc post: https://music-electronics-forum.com/...lation-circuit
I am used to building pedals and guitars but not amps. I made sure all caps were drained and started checking pieces with my multimeter. The resistor that fell out was still good, I raised it off the board with some 14g copper wire (used for wall outlets) - someone on another forum said I should to reduce heat against the board.
I don't know what to check anymore. Nothing looks wrong, but when I fixed the resistor and plugged it into my speaker cab, it gave me a load pop and buzzing sound like nothing was coming through. What should I check next? Any ideas? Thanks!
Pictures: https://drive.google.com/drive/folde...Z_?usp=sharing
Note: I have a Klein mm420 and when I try to test bigger caps (3300uf), I get OL. I didn't realize my tool wouldnt be able to test everything. Maybe I should return it and get a better one?
Edit: Someone told me this -
That resistor looks like it feeds a voltage regulator.
Could be a shorted regulator transistor or a short in the DC path.
Would take some testing to determine.
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