Electric guitar troubleshooting

Question

Went to look at a guitar yesterday and I'm trying to diagnose some of the problems it had before I potentially buy it. It's an LTD Alexi laiho 200 so single volume control and a single EMG 81 in the bridge position.

Guitar has very little volume when plugged in. The amp and the lead were tested successfully with other guitars so it's not that. Also tested with a number of new batteries for the 81 so not that either. The input jack was loose so owner had previously resoldered it, found this problem, reversed the wiring of the jack to see if that was problem, and found no difference.

The volume control does nothing, doesn't lower, higher or turn the volume off when you use it, guitar just stays at a constantly low volume. Also, when you touch the metal dial for the volume control you get earth hum. That's pretty much all the info I have as it was late and I still had a 90min drive home to do so only had time for a quick look.

I'm not afraid of a fixer-upper or redoing the wiring as I've done a few guitars in the past but I've never come across this combination of problems before. The wiring definitely needs to be redone but my fear is that the pickup is somehow damaged too, which I know is rare, so I'm wondering if anyone with a bit more experience can enlighten me as to what exactly is the cause of the problems so I can fugure out if it's worth pursuing.

Answer 1

First, you have to get a schematic for that type of guitar (you say it is a Alexi laiho 200, LTD.) Research the internet for that make and model of guitar. Once you get it, start tracing out different parts of the circuit, highlighting the schematic as you go, if you find an error then, desolder and resolder (yes, you need to know how to solder!) the proper connection. See I don't know if someone got into this guitar and jacked with the wiring or not, you'll have to pick up on the tell tale signs of that, cold solder joints, wires a rat nest, poor connections..etc etc..

Pickups are hard to damage, unless they had a power surge, that is the only way to blow a pickup! You could have dirty switches, or they maybe wore out, not switching properly. You can check the switches with a digital multimeter(continuity). The pots on the volume/tone knobs could be dirty or wore out, you can check them with a digital multimeter to see if the resistance(ohms)goes up or down.

If someone has jacked all the wiring up, and your finding several mistakes, then you may need to rebuild the electronics and electrical wiring of the guitar. Get new pots for it, and a new switch, 3-way or 5-way. You say the input jack was messed up, maybe a new input jack. You can get all of these parts on the internet. You should see about replacing the wiring and do a neat job on the wiring, no rat's nest!

This could be a good project guitar for you, electronics rebuild, maybe a new coat of paint, while you got the electronics gutted, it's a good time for paint work. You could also put new pickups in it to your flavor, EMG has a hell of a website with pickups, so does Seymore Duncan. Rebuild the guitar, paint first, then wiring and electronics, once you got it re-assembled, verify that it works, plug it into an amp, see what happens. There is no room for error on the wiring, either it works or it don't. You can tap on the pickup with a screwdriver to verify that the circuit is working before you string it, cause you'll hear the metal screwdriver tapping through the amp. String it with a set of 9's, just for the setup process, so you can get your truss rod adjusted and check for dead frets, and intonation adjustment. Setup goes smoothly with a set of 9's, I think, cause you'll only have to change little things if you go to a heavier string gauge. Major setup with 9's is a good reference point to start the setup process (string height, intonation, neck relief, frets etc..etc..) Plus 90% of guitars come from the factory with 9's.

I think this is a good project guitar for a beginner to learn all the mechanical/electrical aspects of the guitar. Plus once you get it finished, when you play it, you'll have a sense of pride in your work. Good luck!!

Answer 2

Guitar electronics generally are quite simple. Best if you like how the guitar plays and it is cheap then get it because 99.9% chance you can fix it without too much work.

The volume issue could be 1: Volume pot is bypassed. 2. There is a short that causes the volume to be bypassed and the low volume is the high impedance short(such as a single strand of wire shorting out). 3. Thing scan be wired up improperly. 4. The pickups could be shorted but the volume pot would generally work. 5. Pot can be bad.

At most you would simply have to replace all the electronics for a few hundred... but you'd learn from it and be able to upgrade the guitar to your liking. Ultimately it's about how the guitar plays(it's action, quality, fret level, feel, etc) more than the electronics. (sure you don't want to have to fix it but I'm saying that it is actually easy, much easier than fixing most other issues)

Chances are it is a simple problem. What it sounds like is an open. A wire became disconnected. There is a path that the signal can flow through but the main volume pot is not functioning. The hum generally is due to such an open. It could be an open on the ground side of things. Chances are it is a simple fix that will probably cost you a 10 minutes... worst case you have to spend a few hundred and replace "all" the parts which is extremely unlikely(great chances are the pickups are good, the pots are good, etc).

Really just sounds like a wire that came lose. But the only way to actually prove that is to buy it. I'm not saying buy it, what I'm saying is that if everything else is feels right then don't let this issue stop you.