You're jamming with your friends and your solo is coming up. You slap your five-way switch to the lead position and. . . BRAAPPP! GBZZZ! KRAKKK! You sound like you just dropped your toaster in the sink.
Or youre in the middle of a sweet and dreamy ballad and you try adding some volume swells. ZZTT! CRRUNCH! You sound like youre chewing popcorn at 120 decibels.
This kind of audio chaos sends most players into a state of panic, visions of expensive repairs and replacement parts dancing through their heads. But, amazingly, most poor-functioning switches and potentiometers (thats volume and controls to you neophytes) can be rejuvenated with a little cleaning.
Let's begin by looking at pickup selector switches. Most fall into two categories: the Fender-style blade switch and the Gibson-style leaf switch. Both are remarkably simple in their function, relying on one piece of metal contacting another to pass the signal along.
Blade switches come out through a long, thin notch in the body and have a knob connected to a flat shaft. If you're brave enough to look inside your guitar, you'll see that this flat shaft causes a tab to run across a series of little contact points wired to the pickups. This is where the problems occur. That tab and those little contact points can become oxidized, causing your signals electrons to start and stop like the rush-hour traffic, creating lots of ugly noise.
A similar problem occurs in leaf switches. Leaf switches come out from the body through a circular hole and have a knob screwed onto a circular shaft. Inside the guitar, this shaft causes pairs of springy metal leaves to connect or disconnect. These contact points suffer from woes similar to those of blade switches.
Finally, let's look at potentiometers. The potentiometer, or pot, is an enclosed metal device about the size of six quarters stacked on top of each other. A shaft goes out to your guitars face and the appropriate knob is attached. Inside the pot is a wiper, which runs across a piece of resistive material. Just like your switches, this contact point can become oxidized or grunged up with bar sludge, sweat, or rehearsal room rot. The quick and clean solution is to flush these contact points with electrical contact cleaner. This magical stuff can be bought in any hardware store, electronics shop, or Radio Shack. It comes in an aerosol can and uses a long, thin, straw-like tube to reach the nooks and crannies where you need it. I know that Radio Shack has its own brand, but my personal favorite for professional use is Blue Shower.
When you purchase any of these products, be sure to read the label. First, make sure that its a general purpose cleaner and degreaser and that its safe on plastics. Second, check the warning precautions. Use this stuff sparingly and wear safety glasses no matter how nerdy you look.
Application is simple. Blade switches can take a spritz right through the opening in the guitars face, then rock the switch back and forth a few times. It helps to have the guitar plugged in and the strings ringing so you can hear when you've eliminated all the offending dirt. Two or three spritzes should do it.
On leaf switches you might want to apply it directly to the contact points. While youre in there, check to see if there is excessive rust on the contacts. If so, use a little extra fine sandpaper (400 grit, wet or dry) to polish them up. Don't use sandpaper on the blade contacts or you ll bend them out of shape and ruin the switch.
Pots also require application from the inside of the instrument. Youll find one or two points that access the interior of the pot. Follow the same procedure as with the switches: strum, spritz, and jiggle, and youre clean again.