1976 Gibson ThunderBird Bass SideWinder Pickup Rebuild [Pictures]- created 02-19-2010

Searcy, Clint - 02/19/2010.19:16:53
MIMForum Staff, Nashville

Paolo was crushed.... The pickup in his 1976 Gibson Thunder Bird Anniversary model was dead. He carried his bass all over Italy asking repair shops if they could help him. But they all laughed at him... "Silly boy... Those things are epoxy sealed. They can't be fixed. Better you should buy a new one.... no?" Paolo called shops in Germany and France and England and Spain. All of them said his quest was in vain.

Finally out of desperation he sent the pickup to me cause I'm made of Magic!

These pickups are not totally sealed in epoxy. Gibson just drizzled epoxy on them to hold all the parts in place and keep them from rattling but the stuff has such an infamous reputation that most pickup guys won't even try to take on this job.

Turns out only one of the coils was dead. They run a little north of 10K each for a total of 20+K when it's all said and done.

Good, strong magnet there. Have you figured out what you're looking at yet? The coils are turned on their sides and the magnet runs down the middle of them with it's north pole facing up. There is a steel blade pole that conducts the south pole of the magnetic field through the coils

See

I know what you're saying... "But Clint... Doesn't all that Epoxy make you want to run out of the shop screaming and put on a dress and cry like a little girl?"

I'll tell you the answer tomorrow... Same MIMF time... Same MIMF channel.

Wow, so he was just flat out refused? Surely somewhere would have given him a ridiculously expensive quote at least? I can't believe he wouldn't have been able to find <i>someone</i> on his side of the pond with the guts to take on the challenge!

Thanks for that, Clint. And is the magnet only half as wide as the coils? (Is there another magnet under that one below the blade?) And does the base plate reflect the magnetic field too, or is that just for a spacer on the sides?

I was just trying to figure out how these worked, and there you opened one up for us.

So cool. Those are pretty narrow bobbins, are they wound with 43awg.

Wow, so he was just flat out refused?

Greg, people hear Epoxy and they just run.

And is the magnet only half as wide as the coils?

Correct! I'll show you in a few posts...

does the base plate reflect the magnetic field too, or is that just for a spacer on the sides?

The base plate is nonferrous and does not effect the magnetic fiend. Maybe some sort of Zink...?

Those are pretty narrow bobbins, are they wound with 43awg.

Would you believe....44awg?

Tell us more about that epoxy's resistance to heat when you get a chance.

It's tough stuff. Heat doesn't really seem to bother it at all.

Now... let's continue shall we?

So now you're saying..."How's he gonna get the epoxy out? Is he going to melt it with a hot knife?... Soften it with some magic concoction?"

Nope... none of that. You see... the epoxy doesn't stick real,well to the base plate so all I do if gently flex the base plate a bit until I get a small gap between the epoxy and the side of the base plate. Then I work a small screw driver into the gap and work it down the length of the pickups. I switch sides after each pass until...

*boink*

Now... lets pull that sand cast Gibson magnet out. Strange looking ain't it?

Maybe now you can see the good fortune of the specific set of circumstances surrounding the mid 70's Thunder Bird. Gibson used Epoxy on lot's of it's mid and late 70's designs. The V2, the Ripper bass, The Grabber bass, The Marauder and many others from this time used so much epoxy to sell the pickups that they are considered disposable should they fail. Just toss them in the trash

But the Thunder Bird is a little different. They only used a little epoxy. The epoxy didn't stick to the base plates well. It also doesn't stick well to the nylon bobbins.

So if you're gentle, persistent and a little bit crafty... there is no reason to toss these pickups when they fail.

Haha, I guess there are a lot of repair-people out there thinking: "Can't sleep, epoxy'll eat me!".

Fortunately there's Clint Searcy. Winds pickups: doesn't afraid of anything.

Good work. Looking forward to more.

Now... see the picture in post 11? The epoxy on the bottom of the bobbins is a little more than 1/16" think. I'd like it to be as thin as possible before I start trying to work it so.... It's off to the bench top sander

There... that's much more to my liking

Now... at this stage I simply try to gently flex the bobbins in my hands. Crack...crack...The epoxy is brittle and will not flex with the bobbins.

Once I get a crack or two started I can work that with some tools. Careful.... The bobbins are flexible... but they will break if you over do it.

Finally the epoxy lets go enough to remove the bobbins.

See the steel blade pole running through the bobbins now? The white plastic bit is just there to keep the blade in place. It's binding material. I see this stuff used as spacers in a lot of 70's Gibson pickups.

As you can see the epoxy is soaked into the coil so stripping the bobbin is no easy matter.

This is where things could go very badly if you're not used to working slow and steady.

Starting to move... don't rush things

Finally....

Love it. And how does laying the coils on their side affect the sound of the pickup?

And why the oversized baseplate and cover? They didn't want the pickup to look skinny?

Thanks Clint

Amazing work Clint, these suckers better sound like the voice of god when you're done done with them.

Any clues in there as to what killed the first coil?

That epoxy looks more like good ole PC-7 than potting epoxy.

Nice work Clint! I've seen photos of the insides, but never taken apart. You know those are a Bill Lawrence design. He did al those 70's epoxy filled pickups for Gibson. You can see his solder tab like he used on the L-500 bobbins. 44AWG? Figures! The patent number for that pickup is 3902394. The baseplate is probably nickel silver.

I've removed totally epoxy'd pickups from plastic covers. It's not easy, but is possible.

>And how does laying the coils on their side affect the sound of the pickup?

It makes it sound like a single coil pickup, since the strings are only sense at one location. A regular dual coil humbucker senses the strings at two points, so there are phase cancelation and reinforcements going on, plus the pickup's aperture is wider.

That's brilliant. I just heard a thunderbird on you tube the other day. Sounded fantastic. Do the Epiphones use the same pickup design, or do they just look the same?

By the way, Bill Lawrence has joined Lace music recently. And the Lace noiseless pickups seem to have the same sideways coils, unless I am missing something.

Some lace pickups do use the sidewinder design. The original EB-0 humbucker pickup was also a sidewinder, but not a Lawrence design. Lawrence L-250s are sidewinders. Q-Tuners are sidewinders, as were some Lane Poor pickups.

Lace is distributing Lawrence's Wilde pickups due to his health issues, but the two companies did not merge. Bill did move his workshop into Lace's though.

Hey Clint, how many turns of wire did you end up with?