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Denon POA-2200 Power Amp repaired but getting hot.....any ideas??!

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doctorhugocat

Hey everyone -

A while back I got hold of a broken Denon POA-2200 power amp: I've always wanted one. I took it to pieces and found dry joints on the same transistor on both left and right channels. I re-soldered the joints and it works fine and sounds great!!

BUT: one of the channels is running hotter than the other: this can't be right surely? It's basically a dual-mono kind of setup (see pic). Each channel board has a large heatsink. When I repaired the amp I made sure I used new insulators and compound on the transistors...... Now, the right channel's heatsink is stone cold, the left channel's heatsink is very warm after 20 minutes. Not too hot to touch, but very warm.

Surely this can't be right? Any ideas?

Any help appreciated!! Or if someone can suggest a better forum for the question, please do....I posted to Audiogon earlier, but then thought that this might be a more suitable place......

B

Follow Ups:

RE: Denon POA-2200 Power Amp repaired but getting hot.....any ideas??! - doctorhugocat 15:13:56 04/03/13 (1)
Many thanks! I've found a service manual so the first thing I'll do is check the DC offset. As you say, I was slightly surprised that the other channel was stone cold, but I think my 'hot' channel is still a little too toasty for comfort.
- RE: Denon POA-2200 Power Amp repaired but getting hot.....any ideas??! - Blackdog 18:35:41 04/09/13 (0)
  It's not offset you want to check first. It's bias. Two different things.
RE: Denon POA-2200 Power Amp repaired but getting hot.....any ideas??! - 6bq5 09:31:09 04/03/13 (0)
Is it possible that a bias resistor was adversely affected from the "dry solder joints" and is biasing one channel higher than the other?
Just a thought - seems to me if one channel is hotter (temp) than is is most likely a bias problem - conversely the cold channel could be running too low!
Happy repairing

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