tomcaster
Halfnote
Posts: 91
Formerly Known As: strat-hacker
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Post by tomcaster on Feb 11, 2020 12:24:46 GMT -5
I have a lonestar amp that was fading out. I replaced the the power tubes and it was fine for a few hours and now the problem is back. It fades in and out much faster though-it's usually out for no more than 15-30 seconds. A friend is saying it can't be the pre-amp tubes and I should just take it in to a shop. What do you guys think?
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Post by Leftee on Feb 11, 2020 12:34:41 GMT -5
You can try preamp tubes. It wouldn’t hurt. Even just reseating them. But it might require a trip to the Dr.
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Post by Opie on Feb 12, 2020 7:48:42 GMT -5
I'd look for a failing cap somewhere.
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Post by BluzLvr on Feb 12, 2020 12:09:12 GMT -5
I agree with the cap response.
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pdf64
Wholenote
Posts: 558
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Post by pdf64 on Feb 16, 2020 18:14:26 GMT -5
A slow smooth clean fade out / in usually indicates an intermittent connection to a tube heater. Mesas can be tricky to work on, so taking it to a competent tech is a good idea.
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tomcaster
Halfnote
Posts: 91
Formerly Known As: strat-hacker
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Post by tomcaster on Mar 2, 2020 12:05:59 GMT -5
Thanks for the replies. Never knew this was a thing-they re-tensioned the tube sockets and all good. I'm a front of the amp type of guy.
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Post by LTB on Mar 4, 2020 2:45:41 GMT -5
Thanks for the replies. Never knew this was a thing-they re-tensioned the tube sockets and all good. I'm a front of the amp type of guy. I was about to suggest checking the tube sockets for loose connections as problem cleared when you replaced tube then eventually returned.
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Doug In Idaho
Quarternote
Posts: 37
Formerly Known As: BlackGibson
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Post by Doug In Idaho on Mar 9, 2020 10:22:23 GMT -5
So ummm... how does one go about adjusting tube sockets? I've got a bassman that got smacked around a bit. a few of the tubes were actually broken and all were bent out of shape. I replaced everyone and now the power tubes get really hot and the amp cuts out. Any suggestions?
thanks, db
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Post by LTB on Mar 10, 2020 4:55:07 GMT -5
So ummm... how does one go about adjusting tube sockets? I've got a bassman that got smacked around a bit. a few of the tubes were actually broken and all were bent out of shape. I replaced everyone and now the power tubes get really hot and the amp cuts out. Any suggestions? thanks, db few different methods but the one I use is say a dental style pick and very carefully close them down slightly by inserting the pick (small pointed tool) between the pin tube and the tube socket and very gently close it. Each pin tube on the socket has a split on one end. I close it just enough that it is no smaller than the smallest diameter pin tube on the same or another socket. In order to keep from spreading a pin tube you need to carefully insert the tube into the socket. When removing a tube just slightly rock the tube while pulling up on it (sort of like pulling a tooth).
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pdf64
Wholenote
Posts: 558
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Post by pdf64 on Mar 10, 2020 7:04:19 GMT -5
As is hopefully obvious, the amp must be unplugged from the wall outlet and totally deenergised 😀 The old FDP amp repairs sub forum had a very good sticky thread on the topic, well worth investigating if you’re looking to learn more. billm’s site has a nice page on it billmaudio.com/wp/?page_id=171
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Post by LTB on Mar 10, 2020 20:15:03 GMT -5
As is hopefully obvious, the amp must be unplugged from the wall outlet and totally deenergised 😀 The old FDP amp repairs sub forum had a very good sticky thread on the topic, well worth investigating if you’re looking to learn more. billm’s site has a nice page on it billmaudio.com/wp/?page_id=171Glad you added this about power and decharging caps. I found it discharged well buy turning amp on, connecting guitar and strum it while pulling the power plug (not turning off). Still use a voltmeter to verify.
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Post by roly on Mar 11, 2020 1:50:05 GMT -5
The symptoms you describe definitely point to a heater supply issue. (fade in, fade out) Either a cold solder joint or a tube socket that needs to be retensioned.
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Doug In Idaho
Quarternote
Posts: 37
Formerly Known As: BlackGibson
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Post by Doug In Idaho on Mar 11, 2020 12:41:14 GMT -5
Thanks for all the help guys, it's appreciated! Since all the tubes were damaged in shipping I figured that the sockets were a good place to start. Will let you know how it goes. Thanks, db
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