cleaning scratchy [electronics] pots / switches

[Jules Richardson]

Picked up an old Kenwood tuner/amp for nowt a couple of days ago - I love all that old 70s/80s hi-fi stuff. All seems to be working, but has a major case of the crackles when the volume control or input selector are used. Despite all the putzing around with vintage kit I've done over the years, this is the first thing I've had where it seems like the pots and switches could do with a good clean.

So... does isopropanol work? I've used it on all sorts of other electronics-related cleaning tasks over the years, but I've seen mixed reports online about it for use with pots, with some folk saying it's OK and others saying it'll destroy lubricant inside the mechanism (the latter does seem like a valid concern, but I'm just not sure if it's being over-cautious - or if whatever lubricant was used has long since ceased doing a useful job in this thing anyway) .

What about ipa to clean, followed by a little mineral oil down the pot/ switch stem to work as a contact lubricant? Or is that asking for trouble, too?

I'm trying to avoid the week's wait it'd need to get some conctact cleaner shipped here - but if that's the way it has to be, then so be it :-)

cheers

Jules

[John Williamson]

Switch cleaner would be better for the pot. The problem may be wear of the track rather than dirt, though, on an amp of that age. I've seen pots where the base material has been visible through a gap in the resistive maerial. For the switch, any contact cleaner should do the job, just check to make sure the plastic isn't going to be affected by the IPA.

Crackling on volume controls is often caused by DC leakage through coupling capacitors, so check those, too.

[Huge]

Judging by the colour of what came out of the input select switch on my Arcam Alpha 9, and the results, I can strongly recommend "Deoxit" switch cleaner. It's rather expensive, though.

Those who followed my "Arcam Input Selector" thread from a couple of weeks ago might like to know that the Deoxit fixed the switch about

95%. There are now clear, crackle-free positions on the input selector. Sadly, they don't line up with the detents on the switch. :o(

[tony sayer]

Spray/product_1150

19 odd quid a can!. Glad me Servisol which I expect is the same stuff is around 3 quid..

Course if Russ Andrews was to make this then 500 notes a 10 milli litre bottle anyone;?..

[John Rumm]

I have had this problem on a couple of amps. One I did using proper contact cleaner, the other (also a Kenwood as it happens) I used WD40. To be fair the WD40 did the better lasting job it seems!

(squirt into the pot from the back - same for the switch, then work back and forth repeatedly for a bit)

[The Natural Philosopher]

get the pukka switch cleaner

[Ian Jackson]

Quite. WD40 is the sort of thing that any self-respecting d-i-yer usually has about his/her person. Some pundits roundly condemn it as a switch and pot cleaner/lubricant, but I find it usually works just fine.

[Jethro]

WD40 is an oil, of some description. It's great for repelling water, and soaking into threads. But it really has no place in electrics.

When I worked in the motor trade, I would despair of people - egged on by the AA - who thought a spray of WD40 was actually a full service. In reality, the *proper* job was to keep the HT leads clean, to prevent moisture settling. Once WD40 had been used, you'd get a layer of grime, which actively trapped moisture, and made it impossible to start the car.

[Ian Jackson]

In message , Jethro writes

I would never use WD40 on things like cables (especially HT leads) unless I could wipe most of it off afterwards. But pot and switch cleaner/lubricant is a different matter. My tiny Electrolube dispenser got used up about 40 years ago, and I've been using mainly WD40 ever since.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jethro saying something like:

And often you'd get deterioration of the leads themselves, through the WD40 acting as a solvent on the covering. Turned some of them into a sticky mess, it did.

[Matty F]

I don't seem to have any HT leads. There's just a tiny spring between the coil and the plug! :)

[Terry Casey]

Don't know what it is these days but RS switchcleaner used to be carbon tet with a bit of oil added and worked on most things, provided they weren't too bad. Electrolube was better and worked on virtually everything!

However, it is surprising just how good a job oil on its own can do. I don't know what they put in 3-in-1 but it is surprisingly effective.

[Graham.]

Try Colmans mustard. It is (or was) made by the same company as 3in1 and WD40 so it *might* work ;)

[Ian Jackson]

In message , Graham. writes

I was once told I could use mustard (instead of Radweld) to seal car radiator leaks (big mistake - it didn't work, and it didn't half stink!), but even I wouldn't try it for fixing noisy pots.

[Gary]

I was in the repair industry for 30 years and the use of WD40 by the public was great. It used to make a little problem into a big one and give me lots of work.. Remember WD40 is an insulator. ( that's why it is used on car ignitions) contact cleaner is not a insulator. it is a cleaner.

[geoff]

Basically an oil

and a good job it is an insulator, can you imagine the effect if it wasn't and you sprayed a conductive film into e.g. a 1meg pot?

[Tabby]

You can use any solvent to clean it. Whether some of them are a good idea is another matter. Alcohol and IPA contain water, which conducts & corrodes WD40 contains white spirit and oil. The iol left behind picks up grime, making the problem worse later.

There's really no reason to buy proprietary overpriced solvents, all are available at a fraction the price in unbranded form.

I'd try paraffin first, as it evaporates fully and is relatively harmless.

NT

[John Rumm]

Yup I have heard all the horror stories as well, however it is also only fair to report some of the successes.

My KA3020 has a working input selector switch and noise free volume knob still a couple of years later, whereas before the input selector would frequently lose amplitude on one channel or introduce a crackle, and turning the volume knob would attempt to proper the speaker cones across the room. The Alpha 8R was the same on the volume knob. That was cleaned with a Servisol contact cleaner. It also improved it dramatically, although a small amount of noise has crept back in.

This is a small sample of no statistical significance, read into it what you wish.

[Ian Jackson]

In message , Tabby writes

The main argument against WD40 and the like is that it is a lubricant, and eventually attracts grot. While this is probably true, surely purpose-made cleaners things like Electrolube are also lubricants?

[Gary]

I often had the problem. Switches sprayed with WD40 became intermittent. Sprayed with switch cleaner and they worked.

Same with pots. WD40 made them OC cleaner got them serviceable again.