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Problem with AD30 single channel....

Posted: Fri Apr 24, 2009 9:23 pm
by BrianPhase90
My AD30 crapped out the other day on me. It went to about 1/5th of the volume it normally has. I ordered a full set of tubes to replace the existing ones. This didn't help. I took the head apart and on the chassis the resistor in the R33 position's lead was disconnected from the board. I soldered it back on but to no avail. Same problem.

NOTE: This resistor didn't match the resistors around it. Indicating it had been changed before. It was 5W though. I took it to my amp tech and they are moving their shop, so they won't even take it for nearly a month. He did say it wasn't the exact resistor that goes there. He also stated that it could have been a power tube gone bad that caused the issue. I'm pretty sure the EL84 in this position wasnt nearly as hot as the other three. I'm leaning towards this resistor being bad, and am hoping that the CORRECT resistor coupled with new tubes throughout will be enough to get her running again. Hopefully not something else waiting to unmask itself.

Can someone tell me where to get this resistor? I have included the schematic below. ... AD30_1.pdf