Last night at my bands practice my '75 Peavey Roadmaster was in standby mode and just started smoking and smelling pretty bad. It was fine all practice and all the tubes were still lit up. I turned it off right when I noticed so but im sure that it doesnt work anymore. I have attached a schematic. Any ideas on what might have happened? Im not to familiar with audio amps as I have only had expierience working with RF tube and transistor amps.
Thanks
Jeff
Thanks
Jeff
An externally hosted image should be here but it was not working when we last tested it.
First thing to do is look inside and see what's been smoking, components smoking is a really good clue to what's happened.
So see if you can find what it was, and tell us the component number.
So see if you can find what it was, and tell us the component number.
if it smells really bad, its probably the output transformer. pro-audio techs call it "the smell of death". if it smelled like fish oil, it's probably an electrolytic cap, which is one of the most vigorous producers of smoke when they go bad. they look like small aluminum cans. look inside to see if any of them are bulged, or have the shrink label melted. after that comes burned components like resistors and diodes.
Power is not supplied to the output transformer in standby mode. That would make it seem less likely to smoke in standby.
Bassen, if you can handle RF tube circuits and SS amplifiers, I can't imagine why you couldn't troubeshoot this circuit.
Bassen, if you can handle RF tube circuits and SS amplifiers, I can't imagine why you couldn't troubeshoot this circuit.
i tried magnifying the schematic with irfanview to see what power supply rail went to what part of the circuit. i can identify the screen supply and the plate supply easily enough, but where does the rail from the bridge rectifier go to?
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