Scratchy Volume Pot - Help

[David St Hubbins]

Is there a quick fix for scratchy pots on an amp? This is that cracking/scratchy sound on the volume knob. Is there a spray or something that can be used without opening the whole amp up and pulling the pot out? :confused-smiley-010

[Ripper]

Gotta spray them from behind to get it to work. Make sure you get a spray that has a good flexible hose as sometimes those pots are hard to get at.

[Wild Bill]

Is there a quick fix for scratchy pots on an amp? This is that cracking/scratchy sound on the volume knob. Is there a spray or something that can be used without opening the whole amp up and pulling the pot out? :confused-smiley-010

There are lots of sprays on the market but you ARE going to have to open up the amp!

You might find a product at Radio Shack or the Source but you'd be better off seeking out a real electronics parts store that caters to local servicemen. You want an aerosol contact cleaner designed for switch contacts and controls that leaves nothing except maybe a bit of silicon lubricant and is safe for plastics. If the can doesn't specifically say it's meant for volume controls then it's probably not a good choice.

When you've got your spray can you've now got to get it inside the control. The can comes with a plastic wand that will let you poke it into places but it CAN"T spray from the outer shaft of the pot into the dirty innards! You have to get at the body of the pot, which means opening up the amp. The pot will likely have some opening (usually beneath the connection terminals) where you can get the spray inside. You give it a quick zot, turn the control shaft a few times to wipe the resistance element clean and you're done.

Some pots in some printed circuit board amps make it almost impossible to get at an opening. Another reason to buy an old vintage amp that doesn't use a printed circuit board. Some pot makers are incredibly cocky and totally seal the body of the pot. So the dust gets in but the cleaner can't - go figure.

Sometimes a pot wears out and cleaning won't help. Or a cap goes leaky and lets DC flow across a pot, which adds scratchiness. Both these things are rather rare, fortunately.

If the pot is truly worn out then you'll have to have it replaced. One thing you should never do is use something like WD40 or any non-electronic oil-based spray. It will make the control quiet as a mouse for a week or two. By then it will have totally dissolved the resistance element inside the pot and it will be totally "snackered". I've seen this happen all the time. The most expensive incident was at a local studio where it was done to a slider on the main board. Sliders are rarely a standard part you can buy from an electronics distributor. They are always custom shapes bought by the equipment maker in production volumes. In this case the maker had gone out of business and there was no longer any source of replacement parts. A $30K board was left with a dead channel.


Wild Bill

[ronmac]

http://store.caig.com/core/media/media.nl?id=1410&c=ACCT113328&h=cfc6dc24b06e6668a7a1


This is the best cleaner/lube I have found. It is expensive (~$15) but well worth it, IMHO.

It is also a very good way to extend string life! Rub a little into the strings when new, clean after every use and you can easily double the life of your strings.