Wiring issue - Epi LP Special II

[Brow]

Hey guys.

I've recently been hired by a local school to work on a few of their guitars to make them 'playable'.

They don't need to be professionally set up or anything, just passable for the kids to 'pluck about on'

I've taken a look at the wiring of the Epi LPII that I have in my possession that belongs to the school, and I can't find a problem with it!

All the wiring appears to be correct, and un-touched. But when the guitar is plugged in I get no sound when I tap on the pickup polepieces with a screwdriver.

I managed to get some grounding noise from the guitar when I unscrewed the jack socket and touched the lugs with my fingers. This noise continued on all 3 pickup settings and died down when I turned the Volume and Tone controls. This leads me to believe that the Switch and Controls are ok (otherwise the noise wouldn't come through right?).

Could the problem be the pickups? Any other suggestions as to what the problem may be?

Thanx for help and advice guys.

Craig

 

[marvar]

Re: Wiring issue - Epi LP Special II

Just because you get a hum or buzz doesn't mean the switchs and controls are ok, you get a buzz any time you have a grounding problem. Do you have access to an ohm meter? The best way to check for electrical problems.
Also note that EPI's are notorious for bad switches, and cheap pots.

 

[marvar]

Re: Wiring issue - Epi LP Special II

P.S. When you touch the output lugs with your fingers, you are just shorting out the circut between the cord and the amp, the same as when you touch the end of a cable not plugged into the guitar, but plugged into the amp. You need to think of electronics kinda like a river- it starts as a stream, and flows down, from point A to point B and beyond.

 

[WhoFan]

Re: Wiring issue - Epi LP Special II

I had a problem with both of my Epi's electronics..... I have started to replace the pots and switches as they are poor quality on those guitars! My Epi Exployer had no sound coming out of it either..... One of the pots soldering lugs was touching the side of the electronic rout and it has covered in sheilding paint..... It was completetly grounded out.... I replaced the pots anyways as that guitar was full of shorts... I used quality pots and the guitar works great with the original humbuckers..

WhoFan

 

[Brow]

Re: Wiring issue - Epi LP Special II

Thanx for the posts guys.

Yes I do have a Multimeter So I guess I can go through and try and work out what's wrong.

Is there any little tests I could do to try and narrow down what the problem may be?

Craig

 

[mnbaseball91]

Re: Wiring issue - Epi LP Special II

If I had to guess, I'd say there's a wire somewhere that's taking the hot to ground. It's easy to miss stuff like that on cheap mass produced guitars because all the wires are in heatshrink tubing with eachother. Check each of the pots and make sure there isn't an extra ground somewhere.

 

[marvar]

Re: Wiring issue - Epi LP Special II

Well, generally, pickups don't go 'bad' as there are no moving parts or things that can wear out.Wires can break, but chances are it wouldn't happen to both pickups. Try to find where the pickup lead is attached to the pot, put one lead of the meter on that tab, and ground out the other lead, say, to the top of the pot. You should get a resistance somewhere between 6k and 14k, make sure your meter is on the x1000 setting. If you get these values, your pickup should be ok, then move on to the switch, put one lead on the center tab, the other on one of the outer tabs, move the switch, and see if you get any reading there, be sure to check both outer tabs of the switch . IF you get a reading , then the switch is ok. or no reading at all, then you have an open, or , a short someplace. The usual wiring of guitars is pickup to volume pot (with a lead over to the tone pot) then to the switch then to output. An exception to this may be if there is only one volume and one tone, Then it may be wired to the switch first, then the pots.
Good Luck!

 

[Brow]

Re: Wiring issue - Epi LP Special II

Thanx for the posts guys

The guitar has 2 humbuckers with 1 Volume and 1 Tone control. I'll do as you both suggested and check for any extra grounds that may be on the tone pots, and then I'll try the tests which Marvar suggested for the switch and pots

Thanx again for your help.

Craig