McCarty 594 wiring

[Hesketh]

Hi Guys,
I bought a 594 last week and have had to ship it back to the dealer due to a problem with the pickup selection.

The problem was that the bridge pickup didn't work when the toggle selector was in the middle position, so basically I had two positions with only the neck pickup.

My issue now is that the dealer says it's working normally, so it appears to be one of those annoying intermittent electrical faults, however I don't want to let them send it back to me unless I am sure they've checked everything.
Has anyone any idea what could cause this sort of behavior? I thought initially it might be a dodgy switch, but looking a the switch on the internet I think that it can't be, because the way the switch works the pickup would not work at all if there was a problem, so I can only think of a bad connection, but why would it only occur when both the PUs are supposed to be working at the same time?

I'd be very grateful for any tips.
Thanks
Rob

 

[justmund]

So the bridge pickup was active when the selector was in the bridge position, but inactive in the middle position?

If so, how did you check this? Did you get something metal and tap on each pickup bobbins, or the tone didn't change?

 

[Hesketh]

So the bridge pickup was active when the selector was in the bridge position, but inactive in the middle position?

If so, how did you check this? Did you get something metal and tap on each pickup bobbins, or the tone didn't change?

I had it connected to an amp. Selector in the bridge position, sound, in the middle, no sound.

 

[Tone-y]

Maybe a silly question, but was the neck volume up?

 

[Hesketh]

Maybe a silly question, but was the neck volume up?

It was, yes. Simply flicking the switch to the middle knocked out the bridge pickup, without moving the volume at all (I did of course try changing the volume as well, and the tone, and the coil tap. Nada).

 

[Tone-y]

I think I'm missing something here; there was no sound at all in the middle position? How do you know it is only the bridge pickup that isn't working there?

 

[Hesketh]

Hi Tone-y.
Sorry, I'm not making myself clear.
In the middle position there was only sound from the neck pickup. If I turned the volume on the neck pickup down to 0 there was no sound at all. Adjusting the volume control of the bridge pickup, while in the middle position, had no effect at all.
Having the toggle switch down, in the bridge position, I was getting sound and the volume control for the bridge pickup was working normally, likewise for the neck pickup with the toggle up.

 

[dkilpatrick]

Just a few more thoughts here,
In the middle position if either of the two volumes are turned to zero, it cuts the sound to both pick ups. That is the normal wiring. Maybe the pickup heights need to be adjusted and the neck pickup is not balanced with the bridge pickup in the middle position?

 

[Hesketh]

Thanks dkilpatrick.
I'm not 100% certain now, but I think it was only the neck volume that had that effect, however I admit, I didn't know that a single pot was supposed to work both on both pickups, I thought they were independent. That could be an "oops" moment.

 

[dkilpatrick]

The volumes are independent for each pickup in the middle position, it’s just if either is completely off it will cut both

 

[Hesketh]

Slowly I'm being educated - it's a painful process. Thanks for your help dkipatrick.
Would I be right in assuming then, that, in the middle position, if the volume for the neck pickup were very low, but not zero and the bridge pickup volume were on 10, the guitar should still be pretty loud?

 

[dkilpatrick]

Yes, that should be correct.
That’s is one of the cool features of the 594 wiring, there are many tone combinations by blending the volume, tone, and coil splits in the middle position.

One of my favorites is neck pickup split on full volume and tone and bridge in humbucker at half volume and tone.

 

[Hesketh]

That’s is one of the cool features of the 594 wiring, there are many tone combinations by blending the volume, tone, and coil splits in the middle position.

That's what I expected. Thank you dkilpatrick, you've really been very helpful in clarifying for me what should be going on. Now I just have to work out if that is what was going on.

 

[dkilpatrick]

No problem my man,
Enjoy the heck out of that 594!

 

[garrett]

The volume pots are coupled, not independent. This is why turning down one pickup affects the other in the middle position.

Here is a good article on the topic: https://www.premierguitar.com/articles/21106-mod-garage-decouple-your-les-pauls-volume-controls

In the middle position, turning one pickup down a little makes the other one dominant. As you continue turning it down, the volume of the other pickup will start to reduce as well until it is completely off.

It can come in handy. For example, one thing I like to do is turn the neck down to about 4 in the middle position for a darker, quieter rhythm tone. Then flick to the bridge pickup for leads.