Cleaning old volume pots?

** CO will probably do nothing for your noisy pot. You need a good grease solvent that is slow evaporating and able to penetrate small spaces plus leaves a thin layer of light mineral oil behind.

CRC 2-26 is one such as is the ubiquitous WD40.

Results are almost instant an there is no need to remove the product afterwards as there can be with Deoxit.

Both are also good cleaners for switches and connectors.

Use only as much as needed to get a result - ie not much.

.... Phil

+1 WD40. One little squirt usually effects a permanent (or at least for many, many years) cure.

Ross

Thanks Phil, I'll get some tomorrow hopefully. I only have 808 silicone oil spray and CRC 5-56 which I use for general automotive stuff and as a de-facto cutting oil when drilling and tapping metal. It seems that some

2-26 will be a good addition to the cupboard. Come to think of it I have another Sansui amp in storage with 'slider' linear pots that are noisy too...

Cheers,

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

Thanks Ross.

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

** Sliders are not the same as rotary pots - be very careful how much WD40 is used or you may remove all the grease that makes the traveller move so smoothly.

The very best way to deal with sliders is to remove and disassemble them - clean completely with WD40 and wipe dry with a tissue or rag. Then regrease the traveller to frame surfaces and reassemble.

I have use a white coloured "marine grease" made by Valvoline with success.

Comes up working like new, long as the track and contact fingers are not too worn.

... Phil

Instead of WD40, I use GT85 - same thing except its PTFE enhanced, so far there's been no problems with PTFE particles lifting wipers.

The more recent the equipment; the more likely to be ABS plastics in various assemblies - that stuff disintegrates if you spray it with hydrocarbon solvent.

The old method was rub the track with pencil graphite, but it contains clay which is abrasive. The heavier the black, the less clay, YMMV.

Good info - thanks.

Yes I've found instructions on doing that during my searches for 'noisy volume control repairs' - they say use a 4B pencil. Mind you just as many people say not to do that with equipment manufactured after WWII.

Cheers,

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

Thanks for that Phil. The unit with the sliders is only occasionally used and I'm not sure I'll bother trying to fix it unless it gets much worse. It only crackles a bit at low volumes currently.

I'll head out to try to get some CRC 2-26 in a while. It seems it's not a commonly stocked item even with stores who have a CRC stand or section of shelving so I may have to order it. Bunnings have it on their site for $24.99 for a 300ml can but say not available in all stores and the local Bunnings is very small and usually orders most 'slow movers' in from a bigger store.

Cheers,

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)

I would avoid WD40 or any other product which leaves any oily residue. Great for nuts and bolts, but on electrical contact surfaces it becomes a dust-and-crud magnet.

I know that's the theory, but I've been spraying RP7/WD40 in pots for forty odd years to shut them up and never had a problem. The device has invariably died before pot noise became a nuisance again.

** Superficially, this sounds like a genuine concern - which experience shows is of no consequence in practice. Consider the following facts:

1. The insides of pots, switches relays etc which are themselves hidden inside equipment are not subject to dust. Slider pots may be, but most have curtains protecting them.
2. Metal surfaces coated in an oily film are protected against corrosion due to exposure to moisture or damp air. A coating of light oil has been proved to improve electrical contact by reducing resistance build up as surfaces wear.
3. Pots and most switches have a wiping action between contacting surfaces that displaces light oil. Same goes for connectors.
4. Applying a little WD40 or similar to non-functioning pots, switches and connectors makes them work again in seconds and keep on working.
5. Applying any of the fast evaporating, oil free cleaning products to the same tasks has no permanent effect.

... Phil

Yeah, and that is why you don't use WD40 and similar products on locks as it gunks them up and makes the problem worse in the long run. Locks have keys inserted repeatedly and dust and muck can be introduced that way. That's not really the case with pots.

The concerns are valid to some degree but I've done it many times and it works well.

Well my can of CRC 2-26 has fiunally arrived. However the amp's no longer got available bench space as other projects are underway so I'll try it later [TM].

Oh, I found some Akai ASE-30 two-way headphones for $5 at the Salvation Army thrift store the other day and the pots on those are scratchy too. They also 'break down' when playing 'busy' music (but sound good with jazz etc.) so maybe replacing the ~40 year old 22 uF NPE capacitors inside them will fix that? Here's hoping because I just happen to have some sitting around that were for a speaker crossover re-build that hasn't happened (yet!).

--
Shaun. 

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*." 
David Melville (in r.a.s.f1) 
(*Diagnostic and Statistical Manual of Mental Disorders)