# Scratchy Pot on Crybaby



## GuitarsCanada (Dec 30, 2005)

We may have covered this somewhere along the way but I cant seem to find a thread on it anywhere. I pulled out my Dunlop Crybaby wah after having it away for while and it has a scratchy spot in it. Is there a way of cleaning these pots or some other way of tackling that scratchy spot?


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## dtsaudio (Apr 15, 2009)

They are a sealed pot. However you may be able to get contact cleaner to penetrate. I use Ideal contact cleaner. Available at Home Depot (among other places). If that doesn't work, these pots are available. Absolute Music in Hamilton has them in stock. Pricey though.


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## kat_ (Jan 11, 2007)

A replacement pot is around $25. Most stores don't bother stocking them but can order them in easily.
Wah Pot, Dunlop Hot Potz II ECB24A


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## bleedingfingers (Sep 25, 2007)

If its been sitting for a while just work it by hand a bunch of times when its not plugged in and you might get it to work .
if that doesn't do it Long and McQuade have the pots or can get them.
cheers B.


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## mhammer (Nov 30, 2007)

Pots work by having a movable contact scrape across the surface of a resistive element. I say "scrape" because it only makes contact by virtue of pressure being applied. Generally, the movable contact, or "wiper", is smooth, and the resistive element is hardy enough to withstand a smooth, but pressing, surface gliding over it many times. But pots vary in terms of the degree of friction involved (some glide more than scrape, and cheap one scrape, more than glide), and over time the wiper will _creat_e residue inside the pot by simply scraping away tiny particles of the resistive element, and collecting them into little hard-to-see lumps.

Pots CAN get dirty by dust and other things getting inside, but as the paragraph above illustrates, even hermetically sealed pots can create their own dirt if used enough.

Let's introduce an analogy here that will clarify things. Think of the resistive element as being like a road, and the wiper as being like a tire. The smoothness of the ride is a function not only of what sits *on top* of the asphalt, but also what has been *removed* from it. It could be swept clean by an army of cleaners, but if there are pits in the asphalt, it will still be a bumpy rid as your tire falls in and out of contact with the road.

In the case of pots, the "scratchiness" is analogous to a bumpy ride. The scratchy sounds are a byproduct of intermittent contact introduced by imperfections in the surface; both bumps and dips. Contact cleaner, or taking the pot apart and cleaning it with alcohol and a Q-tip, will remove the "gravel" sitting on top of the asphalt, but it does nothing for the pits worn away from the surface. So, if the pot is scratchy because of dust and exogenous grime, then contact cleaner shpritzed inside is just the ticket.

But what happens if the grime producing the crackling is internally-created grime, scraped off the surface of the resistive strip? Here it gets complicated. There is some stuff which was recommended to me by a buddy with a very busy commercial studio, called "Stabilant" (HOME PAGE -- STABILANT) It is made in Thornhill, ON, and is a contact *enhancer*, rather than cleaner. That is to say, it functions like a liquid solder joint by forming a conductive surface layer on top of the resistive element and/or wiper. I've been using it for a couple years now, and swear by it. Unfortunately, it is often hard to find, and expensive when you do (a new wah pot is cheaper than a shot glass of the stuff), but a sesame-seed-sized droplet of it goes a long way.

The layer it forms is not thick, and since it remains in a viscous state, you can't build up layers, unfortunately. However, in the world of electrons, a 1 micron gap is like the Grand Canyon, and even a thin layer can rectify a lot of what years of scraping a pot has caused. Personally, whenever I get new pots in, I immediately pop the backs off and apply some of this stuff as insurance, then re-attach the backs. It has brought a number of devices back to life for me. However, because of the limitations of layer thickness (and that layer being thinner than the gap between wiper and resistive element), there IS a point of no return, where application of this wonder-stuff will _not_ help.

Still FWIW, I recommend the stuff to anyone operating a repair bench out there, whether the bench is in your home or a store.


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## fraser (Feb 24, 2007)

i was able to use a cleaner on the pots on mine several times over the last couple decades, and it worked.
but the last time- a year or two ago, i had to replace the pot.
used the one kat linked above.


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## GuitarsCanada (Dec 30, 2005)

Thanks for the info guys. It has been scratchy for some time now. Since before I put it away the last time. It has sat for several months now and pulled it out a few nights ago. I could try some of the suggested cleaners but I think my best bet may be to get the new pot cuz I am pretty sure I may have tried the cleaning route the last time I had used it. Appears to be a pretty simple job to replace the pot as well. $25 or $30 bucks is better than scrapping the pedal and buying a new one


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## zurn (Oct 21, 2009)

I replaced the pot in mine, still had the original pot from when I bought it in the 90's. It's completely noiseless now. The pots are made to last longer now and they don't get as noisy. I replaced it in 2008 and it's still completely noiseless.

Bought it from Fermata, pretty much the cheapest place I found. They have two models, the ECB24A and ECB24B

Fermata Music Studios


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## keefsdad (Feb 7, 2006)

How much was it with shipping tax, etc?


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## zurn (Oct 21, 2009)

It was 10$ shipping, no tax.


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