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I have a couple of potentiometers that haven't been touched in quite some time. In fact, probably not in 15 years. So now they produce noisy output, presumably from oxides or some other crud that has built up on the contact surfaces.

Outright replacement might be an option, but these are quite large relative by current standards, they are in fact about the diameter of a quarter and are probably 1/4" inch thick, real 1970's technology. Might be hard to get the same form factor.

Certain retailers used to carry this stuff that came in a can like wd-40, complete with a little red tube for injecting the stuff into exactly this kind of part. You'd squirt a tiny amount into the noisy pot, wiggle the knob 2-3 times, and no more noisy output. So there's the proof of concept that it can be done, but this magic stuff seems to have vanished from the shelves.

It had to just be some kind of solvent, like xylene or something. Any ideas on what would clean the corrosion (dust? dirt? fungus?) off a potentiometer, without damaging it?

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9 Answers 9

up vote 8 down vote accepted

Just spray contact cleaner on it and wiggle it back and forth. :)

It hasn't vanished:

DeoxIT http://www.google.com/products?q=contact+cleaner

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1  
i thought that it must have been banned for burning holes in the ozone, but it's nice to see 'CFC free' on those. –  JustJeff May 6 '10 at 3:57
    
In fact, I just got my own bottles of DeoxIT at Radio Shack. :) –  endolith May 8 '10 at 22:51
1  
I used to use deoxit when I used to work on some old Army radars from the 60s. They were man-portable, and so were always getting exposed to water, mud, diesel fuel, weapon cleaning oil, and whatever else was in the area. That stuff works like magic on internal and external connectors as well as pots! –  Jesse Jul 20 '10 at 17:02

Isopropyl alcohol works well too - You can submerge the pot and give it a good soaking, then just turn the wiper backward and forward a few times to make sure it's well worked in. Then just leave it to dry before turning the electrical equipment back on.

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I have used CRC Electronic Contact Cleaner, to just plain old Windex to clean potentiometers.

It doesn't really matter that much what cleaner you use, provided that it doesn't leave behind any film. So I wouldn't use WD40 or anything that says that it lubricates.

  1. Soak it by spraying it with your favorite cleaner.
  2. Rotate it several times.
  3. Spray it some more to get anything that broke loose out.
  4. Repeat steps 2. & 3. as necessary.
  5. Let it dry completely.

After you have cleaned it you could put in some dielectric grease.

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CRC is available at many automotive supply stores (Advance, Napa), and is cheaper than the Radio Shack stuff. –  Kevin Vermeer Jul 8 '10 at 14:22

I don't know if I'd say it's vanished... in the US, at least, I've seen DeoxIT at Radioshack and Fry's Electronics carries a couple of types of electronics cleaner.

I picked up some stuff (not DeoxIT) that did a cleaning, but it didn't last very long (maybe a couple of months). Deoxit is better, I hear. I was cleaning potentiometers in a 1970s Marantz amplifier.

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1  
Actually I used DeoxIT on my scope and it didn't "last", either. I seem to remember it working well after I used it, but it's back to being intermittent now. Hmmmm –  endolith May 6 '10 at 13:54

I picked up a can of Control/Contact Cleaner and Lubricant at Radio Shack tonight. It was a 4.5 oz. can for around $11.00, a bit pricey, but it should do the trick.

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We prefer you not add signatures and a prefix to your answer. That's what the user badge right below your question is for. Since you seem to be an unregistered user, I removed them for you. –  Connor Wolf Jan 2 '12 at 2:54

You can just clean it with WD40 and then, find a hole on the body (usually it has one!), so put some silicone grease inside, it´s a good lubricating and it´s clean.

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A little 96% alcohol dripped into the pot, twisting the shaft a few times, then drying the excess with a hairdryer - worked wonders for me.

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By all means, clean and lubricate the potentiometer.

However, a pot in an audio circuit should not make any significant scratching noise.

Scratching noise is a sign of a possible design neglect in the circuit: namely, a DC potential across the wiper contact. Quiet operation is ensured by allowing only AC signal through the pot.

Even a brand new pot, especially a cheap carbon one, will make scratching noises if DC is flowing through it.

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if it's dirt you can clean it with isopropyl if it oxides you probably should think more in replacing them because WD40 would never remove the oxide over potentiometers resistance after a time

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