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Repairing Volume Pot?

gdanner

gdanner

Member
With the volume pot on my Fisher 500 being intermittent, I did a search on the Web and found a great article: "The Secret Life of Pots." http://www.geofex.com/article_folders/potsecrets/potscret.htm
It is a great primer on pots.

On page four there is some information on "Tricks" to repair pots. Has anyone tried to disassemble a pot to repair it, especially a Fisher pot? If so, were you successful? Seems like it might be interesting to try...

Oh, and just so I don't get a lot of responses to use deoxit on the pot. I've tried that every way possible.
 
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If cleaning it doesn't fix it, I doubt that disassembling it will. I have disassembled pots to make hybrids and repairs, but if the wiper and substrate are gone, there isn't much hope.

What's the spec on this? 1 MB audio taper with loudness tap and on-off switch? You never know what I might have in the bin . . .
 
The only pot repair I can call a success was a Sony cassette deck with a dead spot at one end. There was a break or gap at the end of the track. I found a conducive paint that completed the track. It contained fine nickel particles.

Most pots can be dissasembled if you don't mind bending a few tabs.

Good luck,
David
 
Neat article. If I had no choice but to repair something this way due to extreme economic hardship or if it was 10 PM on a Sunday and I had family and friends held hostage until I fixed the pot, I'd try it.

Since new pots of this kind rarely run more than 3 bucks, if I've already gone through the trouble of removing it, I'd probably just splurge, spend the 3 bucks and replace it.:thmbsp:

Best,

John
 
The cost is not an issue. My understanding was that the pot was unique to Fisher receivers/amps. If I can replace it with an off the shelf, I'd do it immediately. The faceplate of the 500C is fastened by the volume and tone control. I'm not sure there is a modern equivalent. But I would defer to the Fisher experts...
 
Hey there gdanner,

I was being comical in my post, not trying to be snide--had no idea the Fisher pots were so hard to find.:thmbsp:

Is it the mounting/size of them that's so unusual?

Best,

John
 
I dismantled the 4-layer pot on my KR-9400 to fix a bent wiper and remove the stupid ball detent. With a bit of care, all went well and it works perfectly now. Just bend the tabs gently.
 
That's one reason I got my first parts unit. It just happened to be a 400, but the volpot was the same.
 
audiodon657 said:
That's one reason I got my first parts unit. It just happened to be a 400, but the volpot was the same.
Click to expand...
:thmbsp:

My tube repair wizard mentioned just today, that Fisher used 2 different volume pots in most of the receivers. One much rarer than the other.
One of my 500B's has the rare version of the switch. And unfortunately it's days are numbered. He said it should continue to work for a little while at least, though.
He told me, he could maybe, find me a replacement. But it was at least $50 if not more, for the switch alone, without installation. :tears:
 
Success!

I was able to disassemble the pot and tighten the contacts, plus shift the contacts over just a tiny bit. With careful reassembly, it took a couple of tries, I was able to tighten up the sloppiness of the pot. Perfectly smooth throughout the range now. My son and I set it up with the Klipsch Heresy speakers in mid-refinishing. Sounds wonderful with the recap job from Jim McShane and Triode/SDS. I still have a few things to do, but plan to listen to the setup for the next few days through Christmas.
 
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