Music Man 210 sixty five needs help

[pete993]

Hi people, this is my first post here so be gentle. I have a music man 210 sixty five,about 1977 with 12ax7 and hi/lo power switch, bought on an internet auction site. Worked fine for a couple of days then -
Problem 1. Power light stayed on when amp was in off position.
Problem 2. Amp then blew the main fuse, replaced fuse and tubes. it worked ok in lo power position. Swithed to hi power position and the same thing blew main fuse.
The amp is totally original from new and has never been modded or new parts fitted. Was told the amp has seen very little use so may have been sitting a while not used.
Any help would be great.
Pete

[g1]

That would be 2275-65 chassis. Does the hi-lo switch also have the off position or is there a separate power switch? If the power light stays on (with power switch off), the switch may be bad, the wiring on the primary side of the power transformer could be wrong, or the cap across the hi/lo/off switch could be shorted.
Does it blow the fuse with power tubes removed? If so, filter caps, rectifier diodes or plate protection diodes are suspects. If not, bias circuit or coupling caps could be the problem.

[pete993]

Hi g-one, Yep it is the one with the hi/off/lo switch. Have not took the power tubes out and tried it, I suspect a recap would be the first place to start. Just worried about the cost cause its a 35 year old amp and I fear all you mentioned would probably need replacing. Many thanks, Pete