Gibson U2 wiring problem

[maikel]

Hi Michaelcbell,

When I switch to the neck PU only, the sound that comes from the amp is less loud then when I select the neck and middle PU. This was after my "friend" and the guitartech worked on the guitar. It just doesn't sound and feel right. And I miss the "inbetween" sound when neck and middle PU are selected. The humbucker is connected ok, no problems with it.

JohnH; The SC are connected with red (to the switch) and white (to the ground on pot) wires. It's not a noise issue.

Maikel

[sumgai]

Maikel,

JohnH; ........ It's not a noise issue.

John's question is valid, and needs to be answered, if for no other reason that it will help us to more quickly solve the problem.

If you select just one pickup, and don't play anything, simply listen........ how much background noise do you hear from the amp? (Hum, buzz, that kind of thing.) Now, select the pair of pups, and listen again to the background noise. Did the pair of pups produce more or less noise..... or did it remain at the same level?

This will tell us if there is a phasing issue with your pickups.


sumgai

[maikel]

Hi Sumgai,

thanks for explanation. I will check it this evening and let you know.

Maikel

[UnklMickey]

maikel said:

BTW, What does Exalt and Smite mean below the avatar?

Exalt means you add 1 to someone's karma. Remember how your number was 0 , but it's 1 now?

....hmm? I wonder how that happened? It's another way of thanking someone for helping you, or the community at large.

Smite does the opposite. It's like a slap in the face to someone who has done wrong. I never use that. If someone is doing wrong, I just tell them.

You only get to use exalt/smite once every couple of hours.

If someone like Wolf, were to do something like make you a diagram, in addition to thanking them in words, you could give him an exalt.

[maikel]

Hello Unklmickey,

thank you for clearing that up..I think I have some work to do..

Maikel

[maikel]

Friends,

I discovered something! When I turn the TONEknob down when the neckPU is selected...it works like a bad volumepot. When I do that with neck and middle or only the middle or the humbucker, the sound loosses all the highs, as expected. (Don't know the opposite word for bright). I am sitting here with the guitar and don't understand how this is possible. The neckPU is attached the same as the middlePU. Could the PU be broke?

Maikel

[michaelcbell]

could you explain "...it works like a bad volumepot" - I mean, what happens?

[maikel]

The volume is going down when the tonepot is rolled back. When it's completely to zero it still gives sound, with highs. Not as loud as when it's full open but I think there is still 15% left of the sound. (my estimation) But ONLY with the neckPU. When I select the others, in whatever configuration or in combination with the neckPU, and roll the toneknob back the sound gets dark and loosses the highs.

[UnklMickey]

read this:

guitarnuts2.proboards45.com/index.cgi?action=display&board=wiring&thread=1134247486&page=1

sounds to me, like the neck pickup has a break in the middle of the winding, or is connected through a capacitor.

[wolf]

unklmickey
Wow - that's one heck of a diagnosis you made there !!
I wonder if Maikel has any test meters. That would really "cinch" the cause of the problem.
Also, thanks for explaining "exalt" and "smite" to Maikel. I think I gained a Karma Point.

Well I can't fix a broken pickup but I still feel I can make another contribution to this project. That "solo switch" has had me thinking, especially since the guitar tech said that he didn't know how to connect it. But we are Guitar Nuts™ - we specialize in this kind of endeavor.

Please look at this slightly altered wiring diagram:



I have changed the pickup switches from DPDT to SPST's. No, it is not necessary to do this to the actual guitar but it makes following the circuit a heck of a lot easier.
The other changes I made were to the "solo switch" wiring and the Output Jack's "hot" wire connection. If I have figured this out correctly, the solo switch will now:
1) Turn on the humbucker no matter what switching state the other three switches are in.
2) Turn off both single coils
3) Bypass the volume and tone control
4) Bring about world peace and make us all better citizens. ;D

Well, maybe it won't accomplish #4 but I think it can do the other three. Please check it out to see if this does what I think it can do,

[maikel]

Hello Wolf,

I have an analoge multimeter somewhere around but I have no clue where it is. I have to dig in my toolbox. If you could explain how I should test this PU I will do that and present here the results.

Thanks again for all the help. ;D

[UnklMickey]

I like that drawing, Wolf.

I see a small problem... if you are in the "Solo" position, it will sound a bit different, depending on the position of the bridge on/off switch. If that is turned on, the volume pot will then be in parallel with the pickup, dulling the tone, ever so slightly. What's worse, would be if the volume is reduced. Then the treble bleed pot will also some effect.

You could move the wire that comes down from the left lug of the volume pot to the pole of the solo switch. If that is connected to the upper throw instead, I think that will solve that problem. (the Black wire stays on the pole.)

Yeah, think you're right about the karma thing. I don't put too much stock in karma numbers, though. If that meant anything, you'd be the most underrated member with so many posts.

We all know that's not true.

[ccoleman]

+1 for wolf because I like U2.. but I luv u guys even more

[wolf]

unklmickey
If I have followed your instructions correctly, the proper way to wire the solo switch is like this correct?

ccoleman - thanks for the Karma Point.

As for Maikel - if you find the meter, set it to the kilohm (1,000 ohms) position. Make sure the pickup switches are in the "Off" position. Measure the resistance of the good pickup and remember what it was. Then measure the resistance of the other pickup and if it is noticeably lower, then that pickup is bad.

I know that's a quick explanation so somebody else is welcome to expand on this posting.

[UnklMickey]

Hi Wolf,

That looks great to me.

Checking the resistance of the pickups can even be accomplished without taking the guitar apart. Just plug in a cord, and measure the resistance at the other end.

• 1 - the volume control should be turned all the way up.
  
• 2 - ONLY switch on the one pickup you want to measure.
  
• 3 - the resistance of the volume pot will be in parallel with the pickup. Since the resistance of the pot is much higher (250k), you will still get a fairly accurate reading. Good enough to tell if it has continuity (5~10k for a single coil), or if you are just reading the resistance of the volume pot.
  

ChrisK has more on this type of testing in the Reference Articles:

guitarnuts2.proboards45.com/index.cgi?board=reference&action=display&thread=1176413665

[maikel]

Hi Guys,

I just bought me a new multimeter. Couldn't locate the old one. I have put it on ohms at 2000k. Here are the results.
Neck PU------->592
Middle PU----->007
Bridge PU----->015 (Bridge = humbucking)
Bridge PU----->007 (Bridge = single coil)
N/M PU-------->007
N/B PU-------->015 (Bridge = humbucking)
N/M/B PU----->005 (Bridge = humbucking)
N/B PU-------->007 (Bridge = single coil)
N/M/B PU----->003 (Bridge = single coil)

So UNKLmickey was right. A bad PU. Turning the toneknob in any position didn't changed anything. Now I need a replacement. That will be hard as most PU's have a flange to the bottomplate. My PU's are direct mounted to the body and there is no place for a flange. I tracked down a german guy who has the same guitar and also had a broke PU. He had put in a cheap japanese PU wich sounded ok he said. I will do some research with DiMarzio and Seymour Duncan.

Maikel

[JohnH]

Good tests - and its spooky, I had the same problem, as noted on that old thread that Unk pointed to. Just before you trash the neck pup however, unsolder its leads from the switches and test directly to the pup. If you get no reading, then its busted. But it is still worth carefully unwrapping the coil, to see if the thick wire that you see has become disconnected from the very fine winding wires. You may be able to resolder it. But if the problem is deep, as mine was, then theres not much you can do.

John

[setain]

If its a problem with the coil inside the pup, you could try and rewind it. Its not hard to do, but rather time consuming. If you know what the resistance and the gauge were, it will just be a matter of finding the wire. If you're interested, skguitar.com , galileo.spaceports.com/~fishbake/fpickup/pickup.htm , and members.lycos.nl/ajgp/pickups.html are good to take a look at.

[maikel]

Hello John,

I will try as soon as possible to check the pup for a loose wire. I wonder how this can/could happen, so sudden.

@ Setain; I know nothing more about the pup that it's probably designed/build by Bill Lawrence. But no confirmation about that. I have no technical information or whatsoever about the guitar. I have located someone in germany who has the same guitar. He had emailed gibson and got some info about it.



So a rewire is not an option I guess. I think, if I need a new pup, I would go for 2 DiMarzio cruisers. And that would give me new wiringoptions. ;D I saw on the DiMarzio website that if I order stratreplacement pups I can order them without a flange.

Maikel

[maikel]

The pup is definatly broke. The wires are still connected to the very thin copperwires. The pup is waxed so I can't see a broken wire. Still strange how this can happen.

Regards Maikel

[maikel]

Hello Guys,

I want to say thanks for all the help. I have found someone who can rewind my pup so I will send it the pup to him.

Best regards,
Maikel

[knucklehead]

Is the black axe in the case a Gibson WRC or a U2 ? I just bought one just like it and was told it was a Gibson WRC. Looks dead on to the black axe in the case but has OBL pick ups. Thanks for a response back.