does pot cleaner kill digital encoders?

[pinkjimiphoton]

i know i ask a lot of dumb questions

but i noticed a long time ago it seems like any time any kind of pot cleaner gets near them things, it kills them. working on a cyber deluxe right now. one of the encoders had been broken, was a bear to find. rocketerias in mexico hooked me up. great deal.
but when taking it apart, i noticed unmistakeable cleaner/lube residue all over the shafts of the other encoders, looks like someone had tried to spray them at some point. not surprisingly, none of them work <tho the encoder that is broken is the one for selecting amp models, some of the settings DO work.> that too, internally, was drenched in some kinda nasty viscous liquid.

years ago, i had tried cleaning the contacts in a casio dg20... i mean, like, maybe 87 -88 or so. seemed to kill it dead.

years later, but still years ago, i tried to clean the rotary knobs for my korg ampworks. sure enough, seemed to kill it dead.

so... i'm thinkin' maybe there's a pattern here? <g>

[tubegeek]

Pink, you're gonna wanna refer to my signature block here. Angry Pete knows what's up.

[anotherjim]

Encoders are really just a kind of rotary switch inside. They are going to be pretty feeble switch contacts, like the one that connects a button cell in a digital wristwatch - just a touch of finger grease can stop those working
If it can be cleaned from outside, I think the best chance is something that is thin enough to get in but completely evaporates leaving no residue - so IPA is the kind of stuff to use (the alcohol cleaner, not the beer).

If someone has used something unsuitable, especially with SMD components, the damage can be irreparable as it's impossible to flush or scrub out under the components. I've tried soaking in IPA and sometimes it's worked, but modern digital stuff with high impedance MOS chips and only 3.3v are too sensitive to conductive crap and don't have the grunt to overcome it.

[Rob Strand]

I can't answer this specific question but there is some technology of cleaners: some lubricate some not, some leave residue some not, some conductive some not.  This type of thing.  I rarely use the stuff.  I use IPA to clean-up rework on PCBs.

Encoders are really just a kind of rotary switch inside. They are going to be pretty feeble switch contacts, like the one that connects a button cell in a digital wristwatch - just a touch of finger grease can stop those working

I remember reading an article on connector reliability some time back.  The connectors are getting so small that the spring forces on the pins are no longer strong enough to push through surface crap and minor oxide layers.   Thinking in these terms, the tiny contacts in the encoders are going to be very sensitive to crap getting on them.   So any cleaner residue could have the same effect as finger grease.

[anotherjim]

An extra problem is that much of the gear with encoders now is going to have 3.3v logic. Low voltage means any kind of tarnish/grease is a barrier. If they had tried to run old organ key contacts from 3v signals the reliability would have been dire, but they ran with at least 12v and still worked even when the contacts looked black!

[amptramp]

There are a lot of formulations of cleaners including pot cleaner and contact cleaner.  Some cleaners contain hexane which as well as being flammable, will soften and destroy anything made of rubber.  You know that soray used to make fan belts on a car stop squealing?  That's hexane, which turns the rubber into a sticky mess.  Others contain tetrachloroethylene which is OK for rubber but will destroy styrene (I ruined the meter face of a tube tester with this stuff once).  You have to know the chemistry of the stuff you are using and the stuff you are using it on or it is probable that you will run into a problem.