Dead pickup??

[ms960]

Here's the situation on my guitar. I'm working on putting a new set of pups in my strat. I've got them wired up and all seemed well until I switched to the neck position. Nothing. It's like the pup isn't there. I resoldered the leads, and nothing again. I unsoldered the leads and measured the resistance, and it was about 5.5k (normal). The other pups measured normal resistance also. I reconnected the leads to the circuit, tested, and it's still dead.

So...Then, I took all three pups off the one pickguard, thinking there may be a bad pot or something, and installed them on an entirely different pickguard, with a different switch and different pots. Got it all put back together, and the same thing. In switch positions 1-4, everything works fine. In position 5, nothing. Same exact thing, only different pickguard with different pots and switch. I know these pots and switch work because I had it on a guitar not too long ago.

Now I'm stuck. The pup seems fine when it's out of a circuit. But installed, it doesn't work. I have a third switch I could try, but I'm not sure at this point what good that would do.

Your help is appreciated before the thing goes out the window.

Regards

[JohnH]

What do you get as the resistance across the guitar jack, at full volume, in each of the 5 settings? should be just under 5.5k, 2.75k, 5.5k, 2.75k, 5.5k

And in position 4 (n+m), if you tap the pup poles with a screwdriver, are you getting both pups or just the middle?

John

[JohnH]

Also, what diagram are you using, and is your 5-way switch identical in layout to it?
J

[ms960]

Resistance at full volume:

1) Bridge: 4.87k
2) B + M: 2.5k
3) M: 5.04k
4) M + N: 5.04k
5) Neck: 250k

And in position 4 (n+m), if you tap thje pup poles with a screwdriver, are you getting both pups or just the middle?

Not sure what you're asking. Do you mean plugged in? How would I tell?

Thanks

[ms960]

johnh said:

Also, what diagram are you using, and is your 5-way switch identical in layout to it?
J

I'm using this diagram:

www.seymourduncan.com/support/schematics/3s_1v_2t_5w.html

And yes, my switch is identical to the one in the schematic.

[JohnH]

I meant to tap the poles while plugged into an amp. But the resistance values show that the neck pup is not connected at any time. At least that eliminates short circuits as a problem, what you have is an open-circuit problem. The diagram is clearly OK.

Normally I'd suspect a dead pup or a bad switch, but you have tested the pup and its OK, and tried it with two switches. Maybe use the meter to check that in pos 4 and 5, the switch poles (the linking S shaped wires along the switch, which leads to the vol pot), is connecting to the lug with the neck white wire.

John

[JohnH]

The way to tackle it may be to test, with full volume and switch pos 5, resistance between:

neck black and white leads
neck white and jack ground
neck black and switch poles
switch poles and ground
volume pot outer hot lug and ground
jack hot and ground

THis amounts to starting directly at the neck pup and working outwards step by step.
All of these should be around the 5k, the last one you have tested as 250k, so clearly theres a fault before then. Hopefully the first, directly across the pup is OK, but if not, it is dead pup or a bad connection to it.

John

[ms960]

Found out the problem. One of the bobbin wires (I think that's the right term) broke. It broke really close to the pup. I tried soldering them back together, but couldn't really get at it (was just melting the base and such). So, it wasn't a wiring problem, which didn't make sense after I put the pups in an entirely new pickguard, pots and switch.

Thanks much for your help.

Mark

[sumgai]

Mark,

Very carefully, unwrap a turn off of the coil, that will give you the length of wire you need to get to the solder joint on the bobbin. However, before you attempt to make the connection, carefully scrape away some of the insulation. Yes, fine as that wire is, there's insulation on it - that's why you couldn't get the two ends soldered together during your previous repair attempt. Scrape with the back side of a small craft knife (such as an Exacto blade). You may cut/break it a few times before you get the hang of it, but don't worry - there's more wire where that came from. ;D

HTH


sumgai