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Fender amp repair

 
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Wilfdell



Joined: 17 Dec 2008
Posts: 3
Location: Granada, Spain

PostPosted: Wed Dec 17, 2008 5:51 pm    Post subject: Fender amp repair Reply with quote

Hi -
I´m trying to fix a Fender Blues Junior amp for a friend. Seems like a simple dry joint or broken connection, but I´m stuck at the first hurdle because I can´t see how to remove the knobs from the pots to get access to the circuit.
Any tips?
Wilf
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kenray
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PostPosted: Wed Dec 17, 2008 6:01 pm    Post subject: Reply with quote

try looking for a small hole on the side of the knobs and see if there may be a small allen screw.
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Wilfdell



Joined: 17 Dec 2008
Posts: 3
Location: Granada, Spain

PostPosted: Wed Dec 17, 2008 6:08 pm    Post subject: Reply with quote

Yeah, I thought there would be a screw somewhere, but I can´t find one at all. Very strange.
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jts1957



Joined: 24 Nov 2008
Posts: 2472
Location: Far, Far Away

PostPosted: Wed Dec 17, 2008 6:26 pm    Post subject: Re: knobs Reply with quote

Smile When all else fails - Force It! Laughing
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Thu Dec 18, 2008 4:02 pm    Post subject: Re: Fender amp repair Reply with quote

Wilfdell wrote:
Hi -
I´m trying to fix a Fender Blues Junior amp for a friend. Seems like a simple dry joint or broken connection, but I´m stuck at the first hurdle because I can´t see how to remove the knobs from the pots to get access to the circuit.
Any tips?
Wilf


"Remove the knobs and input nut.
The knobs are pressed onto the plastic shafts of the control pots. Pull up with even, steady pressure. If knob doesn't come off easily, hold the pot body with your other hand to reduce stress on the circuit board. If the knob really won't come up, use a pair of spoons as levers. Pad the faceplate so you don't damage it."

Here is a good bit of info about the Junior
http://home.comcast.net/~machrone/bluesjunior.htm
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PostPosted: Thu Dec 18, 2008 4:26 pm    Post subject: Reply with quote

Cheers - the first ones I tried to take off seemed set fast and I thought there must be some hidden allen screw or something, but once I got the right feel they all came off fine. Must have been a bit stiff because they hadn´t been taken off for ages.
I´ve fixed broken solder joints on the input, but now i´ve found theres a buzz on the spring reverb when it´s turned up. I´m thinking thats likely to be a blown tube, right?
Cheers
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Thu Dec 18, 2008 4:51 pm    Post subject: Reply with quote

Not necessarily.... Not knowing your skills level, suggest reading the page completely. Seems like there has been some reverb modification due to inherent design issues that may be related or you may have a genuine problem in the circuit.
Do not attempt any modification if you do not understand it.
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PostPosted: Thu Dec 18, 2008 5:07 pm    Post subject: Reply with quote

I´m reading the page now. There´s a lot of good information there, thanks!
I´ll need to have another listen to see if theres a fault there.

I would be confident to do a modification with this quality of information, but it´s not my amp, so it´ll depend how much my mate trusts me!
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Wilfdell



Joined: 17 Dec 2008
Posts: 3
Location: Granada, Spain

PostPosted: Sat Dec 20, 2008 9:30 pm    Post subject: Reply with quote

Ok - job done!
Thanks very much for putting me onto that website vtech, excellent information.
The reverb thing turned out to be inside the spring reverb unit, a broken wire on the coil. At this point the website suggested it might be better to buy a new reverb unit, but I did manage to solder it, fiddly job it was too!
In the end my friend was very pleased with the results, and might get me do do some of the modifications later on. I´m looking forward to that project!
Especially I think it´s a good plan to move the reverb return before the master volume control in the circuit, because it still introduces quite a lot of noise the way its set up.
Cheers,
Wilf
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vtech



Joined: 08 May 2006
Posts: 1264
Location: USA

PostPosted: Sat Dec 20, 2008 9:38 pm    Post subject: Reply with quote

Very Happy
Well done.
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