ES-339 P90 Pro Wiring Problem

[Beantown72]

I recently acquired an Epiphone ES-339 Pro guitar that has some electrical problems.

 

It's a semi-hollow guitar - so it's going to be a bit more of a hassle than usual to sort it out - so I was hoping to get some input from folks to make it less painful than it would be otherwise.

 

The guitar is a 2 pickup (P90-type) guitar, with a 3-way selector switch that has separate tone and volume pots for both pickups.

 

Here is a description of what's going on with it:

 

• Only the neck pickup is ever selected - regardless of which of the 3 positions is chosen on the pickup selector
  
• Rotating the neck pickup's volume pot only has an effect when the pickup selector is in the middle or bridge position. When it's in the neck position, the volume pot always behaves as if it's set on 10
  
• The neck's tone pot always seems to function (i.e. rotating from 10 to 0 rolls off the treble) - regardless of which of the 3 positions is selected
  
• Both the bridge pickup's tone pot and volume pot are always in effect (i.e rotating them changes the volume and tone) regardless of which of the 3 positions is selected.
  

 

Pretty weird stuff.

 

I've been hunting around for a wiring schematic. I can find schematics for a 3 position switch and 2 volume pot & 2 tone pot guitars - but only for Humbuckers.

 

Apart from this electrical snafu - I really like the guitar and would like to keep it if I can sort this out. Any help appreciated!

[Col Mustard]

I am the proud owner of an Epi ES-339 P-90 pro

and I have simply replaced the entire wiring harness in hopes

of preventing problems like what you are going through.

 

The job is a *****... so I don't recommend it unless you are fighting mad.

Or unless you have a good luthier who can do this for you for a reasonable

price.

 

The first suggestion I have for you is to get a can of DeOxit. This stuff has

lots of uses, so it won't go to waste IMHO. Spray into the switch with this stuff

and maybe it will work properly. (This is a faint hope, but worth checking).

It's good for wonky pots on guitars and amps, and for the input jack too.

 

Tie a piece of fishing line FIRMLY to the toggle switch with about 1 meter of line hanging down.

Then unscrew the toggle switch and fish it out through the F-hole. If you go to the hardware

store, you may find some tool that can help with this... kind of a hook on a shaft mounted in

a screw driver handle. Hook the switch and pull it out, leaving the fishing line attached. You will use the

fishing line to pull it back inside and up into the hole.

It's fiddly and exasperating, but this is how it must be done, and if you elect to replace the wiring harness

you'll do this with each component.

 

If the switch really won't work right, replace just this with a switchcraft part, and see if that solves the problem.

 

Here's a link to a page at Stewmac where they show wiring kits for many different guitars.

The cool thing about Stewmac is they supply downloadable wiring diagrams for all the kits they sell.

You could download the wiring diagram for the Gibson SG, and that's close enough to the ES-339

to show you all the proper connections.

 

https://www.stewmac.com/Pickups_and_Electronics/Wiring_Kits/

 

I bought a pre-wired kit that was sized properly for my ES-339, and installed it.

Here is a link... I got mine from Sigler Music.

 

https://www.siglermusiconline.com/collections/control-plates-wiring-harnesses

 

This removed all Epiphone hardware, and replaced it with good quality parts... and I have had no more

problems. You may be able to replace just the toggle switch, and save a lot of hassle and expense.

 

The ES-339 is worth it IMHO. I absolutely love mine. Relatively light, compact and handy, great neck, P-90 tone to

die for... Hard to beat. I wish you well in this. Replacing the electronics in an ES-339 falls into the 'advanced'

category of guitar mods. You might elect to pay a good luthier to do this... once again I feel that the Epiphone

is worth it. We pay so little for these guitars, that in my humble opinion any improvements we must do to make them

dependable is part of the price.

 

The Gibson version cost eight times what I paid for my ES-339, and is still a plywood guitar.

It's more elegant maybe, but elegance wears thin in a rock an roll environment.

So I recommend you speak to the best luthier you can find or afford, and show him the problem,

and pay him what he needs to do this job properly. And then you can enjoy your ES-339... IMHO a totally unique

and very cool electric guitar.

[LongMan]

 

I've been hunting around for a wiring schematic. I can find schematics for a 3 position switch and 2 volume pot & 2 tone pot guitars - but only for Humbuckers.

 

 

You can use a humbucker schematic, as long as it is for single wire + ground humbuckers (coils internally connected). P90s are connected the same way. 4-wire hunbuckers are different though.