Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: seedlings on April 30, 2012, 03:46:02 pm
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Well, this is a new one. 1962 Ampeg B15 needs a couple of new pots (among other things) and the knobs will not come off. One of the knobs, with the set screw out, the knob will spin around the shaft (not totally loose, but it gives enough to go all the way around), but absolutely will not come up and off. I've applied enough pressure to slightly wound the knob - the chassis is flexing 1/4" or so wile prying. Tried different positions. Tried WD-40 overnight for two nights. Driving me nuts...
On the other volume pot the set screw won't come out, and is starting to strip from my efforts.
:violent1:
CHAD
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It look you have to replace those knobs . You have to cut them , broke them...
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It look you have to replace those knobs . You have to cut them , broke them...
Is this common? This is only the second 'vintage' amp I've touched.
CHAD
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The set screw has burred the shaft evidently and has swedged out a piece of the shaft which is why the knob wont just pull off. Your going to have to removed the pot's. Your going to probably destroy the original pots in the process. Grab the pot removed from the amp with a pair of channel locks and pull as you turn the knob off. By the time your done the pot's should be in pieces
Not much else you can do if you really need those original knobs/
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You need a knob puller. Go to StuMac's website and look it up.
In all the years I've been working on Vintage amps, I've only boken one pot.
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Most of the knobs on my '65 Reverberocket 2 are also permanent fixtures. They are pitted with age & look like they washed in from the sea.
Thank goodness the pots are still good.
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You need a knob puller. Go to StuMac's website and look it up.
In all the years I've been working on Vintage amps, I've only boken one pot.
That's a nice item, and pretty easy to make with some square tubing and a dremel. Thanks for the tip!
CHAD
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Also, you could try wrapping the middle of a thin rag or handkerchief under the knob, and pulling up on the ends.
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You need a knob puller. Go to StuMac's website and look it up.
In all the years I've been working on Vintage amps, I've only boken one pot.
That's a nice item, and pretty easy to make with some square tubing and a dremel. Thanks for the tip!
CHAD
I build one with an ABS pipe
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knob pulling;
I would try to salvage the knobs, aesthetics, based on belief that you might drop the value of the amp when you replace the pots, but unless you find period knobs, it will the distract from the aesthetics, will further drop the value of the amp.
Got friend whose wife super glued the radio knobs on her 64 barracuda, I hope this did not happen to the amp you are working on.