Volume / tone control repair, this works

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Volume / tone control repair, this works

Post by LarryC on Mon Dec 26, 2016 10:48 pm

Hi Everybody,
like many of you in acquiring radios over the years we get a fair share where the volume controls no longer function as they should.
Frequently you'll get controls where there are dead spots on the potentiometer as you try to increase volume. In other words the volume suddenly
goes from nothing to almost full volume. The technique I offer here is for controls where the resistance element is still instact and not worn down with grooves or damaged.
An example is from a 1930's Silvertone farm set. The volume control was supposed to read 2 meg ohms but was up over 3 meg ohms, and as described before, it would suddenly jump up in volume as I tried to advance the control clockwise.
I thought about all the possible problems these controls might have in going bad, and it struck me that the connections to the resistive element are only riveted on. Well what happens to bare metal over time?
It oxidizes and develops an insulating layer around it in most cases.
Well short of removing and using new rivets, I came up with another solution. I don't know if anyone else has tried this and I won't claim total credit for it but, I have been looking at conductive glues of late as a useful way of fixing poor connections in various parts of old radios. I thought I would try it out on this volume control to see if it works. In theory it sounds good anyways  pirat
I carefully took the control a part and cleaned the exposed rivets and metal tabs at the ends of the resistive element then I layered on some WIRE GLUE that I bought on eBay, on the riveted ends covering the clean metal rivet and going a bit onto the resistive element. You want the rivet to be making a good electrical connection to the resistive element.
The stuff works and the volume control now reads back a little below the 2 meg ohms it is supposed to be, also it doesn't jump up in volume as it did, the volume increases smoothly now.
To make the connections more permanent and longer lasting, I would go back and apply some thin varnish only over the now dried wire glue to reduce environmental effects on the restored connections to the resistive element.
Good Luck using this idea and pipe in if you find it works for you. Very Happy
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Re: Volume / tone control repair, this works

Post by Bill Cahill on Mon Dec 26, 2016 11:29 pm

Thank you very much..

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