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Bands Using SUNN / Re: Sunn Rigs of Doom 2022
« Last post by ericexists on April 26, 2023, 04:37:53 pm »Oh man this is amazing
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Q & A / Re: New to the group, question about Beta Lead output problem
« Last post by Isaac on April 22, 2023, 11:33:40 am »If you were in western Oregon, I'd be willing to take a shot at it.A common problem with Beta amps is that either the Plus 15V or Minus 15V regulator transistors on the power amp PCB fail. Q1 is the Plus 15V regulator, Q11 is the minus 15V regulator.
Well I'm no repair guy, but is this fixable on my end? I would really like to get this working, but if not I'll sell it as is and buy a Marshall DSL20. I really appreciate the help.
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Q & A / Re: New to the group, question about Beta Lead output problem
« Last post by Isaac on April 22, 2023, 11:32:15 am »A common problem with Beta amps is that either the Plus 15V or Minus 15V regulator transistors on the power amp PCB fail. Q1 is the Plus 15V regulator, Q11 is the minus 15V regulator.That was my next thought. If neither the preamp nor the power amp work, that leads me to the power supply.
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Q & A / Re: New to the group, question about Beta Lead output problem
« Last post by loudthud on April 21, 2023, 06:09:10 pm »Repair of a two layer printed circuit board takes considerable soldering and desoldering skill. Unless you have experience with such repairs, you will likely damage the circuit board just removing the failed components. Also, replacing components at random is never a good idea. Considering the age of Beta amps, a complete re-cap would be the best to insure the amp will operate reliably in the future.
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Q & A / Re: New to the group, question about Beta Lead output problem
« Last post by engineco16 on April 21, 2023, 03:15:40 pm »A common problem with Beta amps is that either the Plus 15V or Minus 15V regulator transistors on the power amp PCB fail. Q1 is the Plus 15V regulator, Q11 is the minus 15V regulator.
Well I'm no repair guy, but is this fixable on my end? I would really like to get this working, but if not I'll sell it as is and buy a Marshall DSL20. I really appreciate the help.
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Q & A / Re: New to the group, question about Beta Lead output problem
« Last post by loudthud on April 20, 2023, 03:42:21 am »A common problem with Beta amps is that either the Plus 15V or Minus 15V regulator transistors on the power amp PCB fail. Q1 is the Plus 15V regulator, Q11 is the minus 15V regulator.
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Q & A / Re: New to the group, question about Beta Lead output problem
« Last post by engineco16 on April 19, 2023, 04:34:50 pm »Something else I thought of. The footswitch doesn't have a both channel switch anymore, been trying to find a replacement and I tried one, didn't work. Then I left the two wires disconnected, then reconnected them as they were since the 80s probably. Right now the footswitch is connected, when I power it on, guitar plugged into both channels and the switch goes between them. Now I disconnected the footswitch, unplugged the guitar and the B green channel is lit up but goes off after short time. If I plug the guitar into A channel slowly, the B channel lits up for 2 seconds then goes off. IDK if any of this means anything, but I think the amp has been that way forever.
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Q & A / Re: New to the group, question about Beta Lead output problem
« Last post by engineco16 on April 19, 2023, 04:21:52 pm »This might help: https://www.audioservicemanuals.com/s/sunn/sunn-beta/5017163-sunn-beta-partial-sm
I tried everything you said and no sounds anywhere, anyway, just the 'pop' when turning it off. I don't think I'm a good enough repair guy to tear it apart, and it's not cost effective to have someone to repair it.
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Q & A / Re: New to the group, question about Beta Lead output problem
« Last post by engineco16 on April 19, 2023, 03:53:05 pm »Just real quick, I'm looking at it right now. I double checked that all the jacks are clean. I then plugged it in normal again, had to try, nothing. Then I plugged my guitar into the Power Line In, no sound, but when I turned it off I got the infamous Sunn speaker pop. I'll try running it into the other amps clean channel. Thanks again for the help.