pup woes

[Dave Hall]

I have a 2 year old Epi ES-339. Its had very light use, mostly acoustic as I use my Ovation . Plugged it in the other day and it sounded odd. When I select the bridge pup, toggle down, its fine but when I toggle middle, both, no difference. When I toggle up, neck, I get nothing.

I thought, perhaps, sticking contacts on toggle due to lack of use so I pulled it out and cleaned the contacts. No joy.

I connected the jack lead to a multimeter and got 8K Ohm on the bridge and middle positions with .6 M Ohm on the neck position.

This, to me, would indicate a duff pup or a wiring fault and I would proceed on those lines if the guitar had seen some hard times over its life but its mostly sat in my office gathering dust.

Can someone tell me how to pull the push/pull pots as I am a bit ham fisted and don't want to break them when I check the wiring.

 

Thanks in advance

 

Dave

[Pesh]

I have a 2 year old Epi ES-339. Its had very light use, mostly acoustic as I use my Ovation . Plugged it in the other day and it sounded odd. When I select the bridge pup, toggle down, its fine but when I toggle middle, both, no difference. When I toggle up, neck, I get nothing.

I thought, perhaps, sticking contacts on toggle due to lack of use so I pulled it out and cleaned the contacts. No joy.

I connected the jack lead to a multimeter and got 8K Ohm on the bridge and middle positions with .6 M Ohm on the neck position.

This, to me, would indicate a duff pup or a wiring fault and I would proceed on those lines if the guitar had seen some hard times over its life but its mostly sat in my office gathering dust.

Can someone tell me how to pull the push/pull pots as I am a bit ham fisted and don't want to break them when I check the wiring.

 

Thanks in advance

 

Dave

 

Hi Dave;

Does indeed sound like you've got a dead component somewhere in that circuit; it could be the pickup, or depending on where you took the reading; a dead potentiometer.

 

When you say "Can someone tell me how to pull the push/pull pots..." are you asking about how to take them out to check or replace?

[Dave Hall]

Thanks for the reply. I've found a useful Youtube clip here:https://www.youtube.com/watch?v=cuGc83-F_Wk for taking the knobs off.

It looks like the bridge pup comes out and everything goes in and out that hole.

[Dave Hall]

I've managed to tease the pots out of the F hole and took some resistance readings. Problem is I'm not very adept at interpreting them and would appreciate some feedback.

I pulled the pup connector off the suspect pot and, assuming green and white are the hot wires for the coil taps, and black is the ground, I got 3.9K from the green and 22M from the white.

I did the same for the bridge pup and got 4.2K from the green and open circuit from the white.

When I connected both pups back up to the pots and measured from the jack ground the the green and white pins I got about 4K from each

 

Does this look like a failed pup?

[Dave Hall]

As a nothing to lose type exercise I thoroughly cleaned all the pots with servisol, let them dry and connected up to an amp. Bingo its working again. Not sure what got dusty but it seems to be Ok.

 

If it was a faulty pup I was thinking of some burst buckers but its academic now as I don't use it enough to justify the cost.

 

Amendment ... It was loose pins on the pup connector.