Bill Lawrence L-250 Needs Some Help or Replacement

[rgand]

I have Bill Lawrence pickups in a Guitar from the 70's. This guitar is apart to get a refinished neck. It has sounded great for years. There is an original L-500 at the neck and an original L-250 in the bridge. The L-250 has always been weaker than the L-500 and to set up the guitar originally the L-250 pickup had to be considerably closer to the strings than the other one. I picked that guitar up recently and it was really brittle sounding and hard to listen to. No amount of height adjustment will get it right. If I lower it considerably, it gets a little better but really faint. What could cause that? Have the magnets finally gotten weak enough to loose their output or is it possibly another issue? The L-250 is a stacked humbucker. I don't want to give up on it without knowing what's going on. Any input on this?

 

[TroubledTreble]

Yeah, that's odd. Magnets don't typically loose their strength just sitting there. If it was stored near a strong magnetic field it could. The magnet may have shifted a little away from the blade. Wait, these were the resin potted ones though, right? Hmmm. Is it the stacked or the side by side? Do you have a way to test the magnetic field strength? Paper clip or something light. If it has very little pull then it's demagnetizing. It actually takes very little field to make a pickup work. IIRC they are a ceramic magnet which almost never loose their magnetism. But it could have been a bad batch.

It's also possible there is a degrading connection internally. It may be useful to test the coils resistance, shake the pickup and test again. I know, sounds strange but I've seen loose internal connections which are very hard to trouble shoot if you can't get at them.

 

[rgand]

Thanks for the prompt reply. The L-250 is a stacked humbucker and the L-500 is side by side. The L-250 is the one with the issue but I checked both for a reference.

The pickup is still in the guitar. I removed the control plate (it's a Tele) and checked the resistance where the wires connect to the controls. The L-250 and the L-500 both checked at 5 ohms. I then plugged a cable into the guitar and tested the resistance at the other end of the cable, using the selector switch to check each pickup. Both pickups then showed 25 ohms each and 25 ohms together.

For a slightly less technical check, I took a paper clip to see which magnet(s) have the stronger pull and the magnet in the L-250 is significantly weaker than either of the magnets in the L-500. I don't know if it makes any difference but the bar in the L-250 is noticeably thinner than the ones in the L-500.

 

[rgand]

I sent a note to Wilde about this. The reply said that the resistance on an original L-250 should be 11 ohms. Mine is 5. It was suggested that I may have a dead bobbin in it.

When I removed the control plate, I noticed that the tape on the end of the white wire was loose so I wrapped it again. I didn't think much about it at the time but in retrospect, if that had grounded on a pot or elsewhere the pickup would be working on only one coil. That would essentially be the same as a dead bobbin. Before I re-assemble the guitar with the new neck I'll put shrink tubing on that wire end instead of tape to eliminate any possibility of it grounding out. If it's still weak, I'll replace the pickup.

 

[TroubledTreble]

I have seen pickups that have a zero ohms test still work. So strange things can happen. I agree it sounds a lot like a dead coil. The thinner blade will carry a little less magnetic field but it should still have a good pull to it. Maybe the two are related i.e. there is a separation going on between the magnet and the blade and the same separation is causing one coil to fail.

 

[rgand]

Interesting that a zero ohm pickup can still work. The whole pickup was always weak and had to be adjusted quite close to the strings to balance with the other pickup set just above the pickguard.

I put shrink tubing on the end of the wire that may have grounded out so that can't ground itself accidentally, now. A quick test with the multimeter shows the resistance for that pickup is now 8 ohms. Whoever replied at Wilde said it should be 11 ohms but this pickup is one of the very first L-250's, probably made in 1979. '79 was the first year of production for the L-500 and maybe for the L-250, so the standard may not have been established yet.

It'll be a while until the neck is finished and can be mounted but I can put another neck on it temporarily with a test string or two. I'll have to go get a couple individual strings to do that since I don't want to break a set. Hopefully this takes care of the problem.

 

[rgand]

I put a neck on it, shimmed it somewhere close to right and strung it up with a full set of Ernie Balls. No improvement. Unless you like the sound of fine crystal wine glasses being thrown into a stainless steel sink, this pickup doesn't make the grade. It looks like the answer is to get another pickup. I'll still keep the L-250 around because I'd hate to toss an original BL pickup, if only for nostalgia reasons.

Thanks for all the help offered on this. I appreciate it. This thread can now fade away [size=6pt]like an [size=4pt]old [size=2pt] pickup.....