Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jerryjg on August 11, 2010, 10:03:10 pm
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After about 20\30 minutes the power transformer on this Montgomery Wards Valco amp I juts bought off ebay ( all original) gets Scorching hot- too hot to touch. The can cap seems to stay fairly cool. Loosk like a decent amp tonewise. Its plays pretty well and sounds good with no 'rice crispies' ( snaps, crackles ,or pops).
Any idea what might be going on here?
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Trannies in old amps, particularly bargain amps of the day, ran hot normally. A metal tranny can run as hot as a glass tube w/o damage. If it can't set paper on fire it's probably not a problem.
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You could test it to see if it has a short.
Disconnect the PT from everything and see if it draws current.
I had a Hammond organ that had a PT that got really hot in 5 to 10 minutes of use. The amp played fine. I disconnected everything and and all I had to do is run it through a light bulb limiter and the light bulb lit up. Replaced the PT.
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Fair enough. You might also try the Jack Darr test to m ake sure there is no voltage on the chassis, set forth in this thread: http://www.el34world.com/Forum/index.php?topic=9833.msg89568#new