Electric guitar tone control fault

Question

I've got Epiphone LP Special II for two years. Some time ago I noticed that tone pot set at maximum or minimum was cutting all lows or highs and the guitar lost power (volume doesn't changes while I was increses vol at amp and it was audible on distortion). Next all sound disappeared and then I decided to change the potentiometer. I bought the same value, but smaller size in local electrical shop and soldered new one in the same way as previous was. I also changed the capacitor.

Now guitar sound ok on bottom string at clean, but at top two, or while playing chords it sound like overdriven though low gain at amp. At distorion it sound like phone call - lows and highs are cutted.

What can I check now? Maybe pickups are guilty?

Answer 1

When you say it "sounds ok on bottom string," are you are talking about the bottom pickup (the bridge pickup) or "treble"/down position on the 3-way switch? If that sounds okay, and it is only the middle and top positions (middle uses both pickups, top "rhythm" uses just the neck pickup), then it sounds like your problem might be something involving the neck pickup or its wiring. The first thing to do would be to double check all your soldering, and check it against the LP Special II wiring diagram:

If you have an electronic multi-meter you can use it to check the resistance (in Ohms) of the pot you changed. In a LP guitar typically 500k pots are used, but depending on where you buy the pot they can often be off by a little bit, or a lot if they are lower quality, and that could cause tone loss. You could also replace the 3-way switch, as those are fairly inexpensive, and upgrade the output jack if you are comfortable with wiring and soldering. It's not guaranteed that this would fix the problem but if you do it right it can't hurt. You also can check continuity with the meter, and make sure all the ground wires are connected to the right places. As far as the details go of troubleshooting an electric guitar's electronics, check here for a previous answer.

If you can't find any problems with your soldering and your wiring looks correct, I would recommend taking it to a guitar shop to have a qualified tech take a look at it. On the other hand, if you could conclusively determine it was a problem with the neck pickup, you could take this opportunity to upgrade that pickup. For about $50-$100 you can get a new pickup that would probably make your guitar sound a lot better (at least when using rhythm or middle setting), or you could get a pair of pickups and replace both for under $150. Again, don't do that unless you can confirm it is in fact the neck pickup to blame.

In the long run though, if you can't fix it yourself, then either paying for a guitar tech to fix it or buying new pickups might not be the way to go, because either of those options could cost $100 or more. It might make more sense to get a new guitar if you are serious about playing. New pickups in that thing would cost about as much as the whole guitar did in the first place, and for not much more money you could step up to something like an Epiphone Les Paul 100 that I have heard pretty good things about.

Answer 2

What is the capacitor you bought? Did you get one of the same type as the one that was there before? Good capacitors for audio, especially guitar applications, are not easy to find, there is a big counterfaction market in electronic components, and audio is one of the applications where you actually note the difference between originals and counterfeits...

My suggestion is that first you double check the soldering, the ground on a pot can be hard to solder if you're not experienced, then check the pins of the pot and if you have a multimeter check for continuity with ground on every pin, the initial volume problem could be something like this. If you see everything is okay, try buying a new capacitor from a decent supplier, also, if possible, buy an indicated capacitor for audio. It should be a non polarized capacitor because you have both negative and positive signs going through it.

This should be a cheap repair, provided that you can change it yourself...

If the problem persists, try to seek assistance from someone experienced, either a qualified technician at a store, someone you know is good with electronics or just someone that has been playing guitar for a long time, maybe they have run into somethign similar and can give you an insight...

Answer 3

This might not be it, but it might be worth a try.

You said that the guitar is a couple of years old. My friend knows a luthier that works almost exclusively on G&L's. When my friend asked if he should use WD-40 to clean his pots, the luthier said no. He said to take each pot, and dial it from 0-10 and back to 0 again, 40 times. Each pot. What will happen is the oxidation will simply fall off the pot.

Worth a try.