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Day of the Zombie: curing an undead Telecaster pickup

Issue 89 June 11, 2009

My friend Ed found this
beautiful Tele with a factory
installed Bigsby in the back
room of a West Virginia music
store. If only it sounded as
good as it looks!

Erick Coleman,
June 11, 2009

Photo: 1967 Telecaster bridge
The guitar sat for three years without any takers until Ed wandered in. He couldn't pass it up. Lately he’s been thinking it sounded a little thin in the treble position, but it had plenty of volume, so he didn’t worry about it.

Then Ed’s bandmates told him he wasn’t sounding so good. That brought him into my shop pretty quick.

I played the guitar for about an hour. Both pickups were working, and they had comparable output. But the bridge pickup did sound a bit thin. Was the sound I was hearing bright and Tele-like, or was it too thin and wimpy? I wasn’t sure. I decided to take a look under the hood to check it out with my multimeter.
I didn't get a reading of any kind with my meter set in the standard 20K range. According to the meter, this pickup was dead. Yet it was still working! What the heck?!
Photo: 1967 Telecaster pickupBefore removing the pickup, I reheated the solder joints in a last-ditch hope that they simply went “cold” sometime in the last 42 years (oxidation caused by sweat or humidity can break down a solder joint, especially if the joint was questionable to begin with).

No dice. These joints weren’t the problem. I removed the pickup by unsoldering it at the flatwork. This is a little trick we like to do to avoid unsoldering the original connections on the pots and switch. This is much less invasive and has less effect on the value of a vintage guitar.

Parts Kit for Tele Bridge Pickup

Photo: 1967 Telecaster pickup removedA zombie pickup?
Curious about what was happening with this pickup I called Tom Brantley, who’s been doing vintage rewinds at Lindy Fralin Pickups for over a decade. Tom has pretty much seen it all.

When I described my “living dead” pickup, Tom said if it were simply a matter of one of the coil winds shorting, my meter would have given me a low reading, which I sure wasn't getting.

He then had me test the pickup with my meter set 20m to see what happened. The readout jumped higher than 15m, and bounced all over the place as the reading dropped from there. Tom said that, over time, coil wires can develop tiny fractures in their enamel coating that open the coil to corrosion, causing a mass of the wires to short against each other. He guessed I’d find that a massive short was causing the pickup to work abnormally: through capacitance rather than inductance. I needed to unwrap the coil and take a look.
Photo: String wrap
Photo: The bare coil
I carefully removed the string wrap that protects the coil. I noticed something odd right off the bat: this pickup was never potted. The string wasn't stiff and came off of the coil wire without sticking.

Fender coils were potted by soaking in either lacquer or wax. I’m told some pickups snuck out of the factory unpotted, but I’d never met one of these in person before!

With the string off, the coil looked clean. It was when I took the baseplate off that I started to see the problem.

Portable Digital Multimeter

Pickup Coil Wire
Photo: Damage on the flatworkThe polepieces have rusted considerably, staining the masking tape that helped hold them in place. Probably from sweat or humidity, or maybe from a reaction to the tape’s adhesive, this oxidation broke down the enamel coil coating. This seems like what Tom was describing.

I unwound the coil by hand to see if I could uncover the damage. As I got down to the last third of the winds I found a powdery white buildup on the wire at the bottom of the bobbin. That was the clump of corroded wires that were causing the problem.

The polepieces cleaned up easily for reuse, and the flatwork was fine other than the discoloration where the tape was.

Bobbin Flatwork Material

Add pickup winding to
your shop’s services

Pickup rewinding fees are typically $35.00-$50.00 per coil, so the Schatten pickup winder is a repair shop money maker.
Photo: newly-wound coil
A quick trip to the winder, and this pickup was ready to go back in the guitar. I decided not to wax-pot the pickup, but instead left it unpotted as I’d found it. Potting reduces microphonics and feedback at high volumes, but Ed hadn’t had those problems (he plays the guitar in church). I kept this pickup as close as I could to its original, oddball self!

Magnet Polarity Tester
I wired it up, and was glad to hear it had a brighter attack with much more meat to it than when Ed brought it in. Ed noticed the difference too, and after playing it awhile he sent me this e-mail:

Hey Erick,
Just wanted to let you know
how pleased I am with the sound
of my old Telecaster. It has
its edge back, especially
through my old Fender twin

Now if I could just learn some
new songs to play.
Thanks so much!


DeoxIT Pot & Switch Cleaner

Tele Day in my shop: here’s Ed’s 1967 Tele hanging out with a pal's Fender Muddy Waters model.

That’s the kind of thing a repairman loves to hear!
Erick Coleman signature

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