P-90 & Humbucker Wiring.

[Off He Goes]

I have a Hagstrom HIIN which I am installing new pickups in, as part of my restoration. It's my first time doing this, and I don't want to screw it up. The guitar has two tone pots, two volume pots, and a pickup switch. I do not know the wiring of the pickps, as its not a name brand, and it did not come with a schematic. I've tried to follow this article http://www.projectguitar.com/tut/pickupwiring.htm but I'm not sure how to do it.

In the neck I have a humbucker sized P-90. There are only two wires coming out of the main lead. A Black one and a white one. I connected the wires to a volt meter. With the black meter lead conneteced to the common socket, and the red meter lead connected to the VmA socket, I connected the black wire from the pickup to the black meter lead, and the white pickup wire to the red meter lead, and when I tapped the coil with a metal screwdriver I got a positive reading, and when i removed the screwdriver I got a negative reading. What does this mean? I can't fully understand the article.

I also have a four wire conductor humbucker, with black/red/white/green wires, as well as a silver ground wire. I do not want to wire it for split coil humbucker, just standard. How do I determine the wire schematic for these pickups.

Anybody want to take the time to help me out, this project is very important, and is taking much longer then I had anticipated, and I really want to play that guitar. Thanks!

[scott from _actual time_]

In the neck I have a humbucker sized P-90. There are only two wires coming out of the main lead. A Black one and a white one.

one of those is going to be hot and one is ground. pick one, wire it up, and see how it works. if you swap whichever one you wire hot with the other one, all you'll be doing is changing the phase of the pickup. which you might need to do if you have switch positions with combinations of the P90 and the other pickup(s). there's often lots of trial and error in figuring out wiring.

I also have a four wire conductor humbucker, with black/red/white/green wires, as well as a silver ground wire. I do not want to wire it for split coil humbucker, just standard. How do I determine the wire schematic for these pickups.

do the same voltmeter test with pairs of wires from this pickup. that will tell you which two colors go with each coil of the humbucker. once you know that, take one wire from each coil and tape them together as the series link. take the other two wires and solder one to hot, one to ground. then it's time for more trial and error. if the humbucker sound is not hum-canceling, or if it's really thin and out of phase, you need to take your two taped wires and swap out one of them for the other wire from that same coil.

a good resource for learning how humbuckers work is this wire color chart from Stew Mac. in your case, since you don't know the manufacturer of the pickup, you'll have to figure out the wire color assignments with the voltmeter and some trial and error.

[Off He Goes]

On the humbucker two wires, the white and green are already connected together. They came that way, and they are brand new pickups, never before used. So are they the series link? Also, does the silver, bare wire go to ground also? Along with one of the coloured leads?

Edited March 9, 2006 by Off He Goes

[scott from _actual time_]

On the humbucker two wires, the white and green are already connected together. They came that way, and they are brand new pickups, never before used. So are they the series link?

that's a pretty good bet.

Also, does the silver, bare wire go to ground also? Along with one of the coloured leads?

yes, bare always goes to ground, with one of the colored wires.

[Off He Goes]

I did some more voltmeter tests. I connected the red humbucker wire, to the common socket, and the black to the VmA socket. With the screwdriver on the coil, I get a positive reading, and when I take it off, I get a negative reading. This happens on both coils on the pickup. Should it? And what do the readings mean?

[scott from _actual time_]

I did some more voltmeter tests. I connected the red humbucker wire, to the common socket, and the black to the VmA socket. With the screwdriver on the coil, I get a positive reading, and when I take it off, I get a negative reading. This happens on both coils on the pickup. Should it? And what do the readings mean?

i have no idea. it should give some reading, but i always thought the reading should be all positive or all negative. but the fact that you're getting any reading means the pickup is producing output. i'd wire it up and not worry about it.

[JoeAArthur]

When you're trying to determine phase of pickups, you should be consistent.

This means you shouldn't tap the pickups with a screwdriver, nor should you wave it around it the air.

I rest the screwdriver on the pole pieces... and then pull it up - once. Whatever that deflection is, determines the phase - and I wire them together based on the same deflection - positive or negative doesn't matter, but same deflection direction does.

If your humbucker is wired correctly, you should get the same deflection on both coils.

[Off He Goes]

When I said tap I didn't actually mean like a slap. I do lay the screwdriver down, and remove it. Not a smack or anything, smoothly.