Ultrasonic cleaning ever help old dirty pots and faders?

I've looked around a good bit here and elsewhere for info on cleaning console modules with ultrasonic baths, but I haven't seen any reference to improving scratchy and noisy pots. I have a friend who years ago had an Amek Angela cleaned entirely via this method, and his recollection was that it helped pot issues along with the switches and contacts. Any experiences here? I'm looking into options for a large early 70's console full of AB mod pots that creak and groan, and have so far been resistant to cleaning attempts. EQ's are the main offenders, being dual concentric 4-banger stacks with 3 different values. Around 60 sets total. They may have to be replaced, but anything else that can be tried first is worth a shot given the scope and cost of a custom order and replacement regimen.

Thanks

If they still slide or rotate in a smooth manner and are just noisy, I would advise against ultrasonic cleaning. However, if you are prepared to totally dis assemble and relubricate everything, and the controls are so gritty to warrant this, go for it. Use an alcohol bath for the solution.

Dissassembly and relube of the pots would be a real time consuming nightmare, though I'm sure it's been done by several people here. My inclination would be to replace them if I've gone to the trouble of pulling them off the circuit boards, which will be a trick in itself. I'm still in speculation mode here; I haven't gotten a price quote on new pots yet, I just expect it to be high.

Thanks

We just sent out two SSL 9000 I/O module strips out to be cleaned. I'm assessing the results at the moment.

Interface Audio in Nashville charged us $100 per strip.

I'll reply when I've had time to assess the procedure. If it works, we're buying "bubba", the HUGE ultrasonic cleaner that allows entier modules to be dunked at once.

Keith

I know a tech that uses a lock lube for seized pots. It has some kind of oil with graphite dust to "fill in the grooves" in a worn pot. A google of ultrasonic cleaning yielded a one gallon unit for $500. perhaps an ultrasonic toothbrush could be used on components in place. And then flush out the crusties with tech spray.

They are pretty clean overall. The pots are the main issue, and they generally feel okay. Reports indicate you practically can't move them at all with the monitors on in the control room. I think I've heard of this graphite dust lube before. The problem with the Mod Pots seems to be lack of a clear way to get anything in them outside of heavy brute force spraying or full immersion in something.

Hey Doug,

I hope i'm not being foolish in offering this idea as i expect that you know a great deal more than me about electronics and audio but...

i had a similar problem with an old 70's console and found (after sourcing heaps of pots) that in fact dodgy capacitors (desk had never had a recap) and resistors that had strayed in value were creating my dodgy pot problems. After recapping the desk that had 70 dodgy pots suddenly i only had about 4 or 5 bad pots...

just a thought...

The only type of capacitor that can cause the "scratchy-pot" sort of problem in my experience is tantalum. they tend to fail leaky or short. Electrolytics tend to fail low-value, or ooze conductive spooge.

Low value usually means bass rolloff. I can't say I see old electrolytics making pots scratchy... and I do a LOT of that.

-Were they in fact tantalums? -If so, I think it whould be helpful to be specific on the subject, rather than leading to a misapprehension by newer readers that "old caps can make pots scratchy"...

Keith

I've actually had bad pot-problems in our Calrec due to very-low leakages in worn coupling electrolytics pre or post the pot - where a pot cleaning would help only for weeks without further work, the same type of cleaning seems to be more-or-less permanent when caps are replaced.

My guess is that this is the basis for the myth about cleaning sprays as being "addictive" to electronics..

Jakob E.

These things definitely have the original electrolytics in them, so I should try one and see. Wouldn't have been my first thought, but probaby needs to be done and far easier than replacing the pots. No tantalums that I can tell, unless they are different package type than I've seen before.

Thanks

There are the cases where bad caps allowing some dc onto
the pots could cause problems of noise , no ?

Sure , the above post didn't mention dc as being the problem ,
but it's not uncommon

..yes, that's my point..

I worked on a silvertone guitar amp last month. No amount of spray stopped those scratchy pots. A quick check with a voltmeter showed d.c. after the coupling caps. After replacing two coupling caps those pots were dead quiet.