Showing posts with label broken pickup. Show all posts
Showing posts with label broken pickup. Show all posts

Sunday 27 June 2021

Fender Lead I Pickup

 I’ve been repairing a few pickups recently and I thought I’d share this one with you. It’s a Fender Lead I Pickup that was sent to me by guitar repairer Jeff Baker from Oamaru.

The Fender Lead I was one of those obscure models that never really caught on and the pickup reflects that. It’s a little unusual and that’s what makes it interesting.

It even looks different with those square topped bobbins.

Fender Lead I Pickup Mr Glyns Pickups

Not only is it unusual looking from the top but turn it over and it shows what it’s really all about. Those are 12 big adjustable poles screwed into substantial steel blocks and coupled to a powerful ceramic magnet.

This is clearly not a typical Fender pickup, this was designed to ROCK.

Lead I Pickup underneath

It came to me because it wasn’t working and typically one coil was showing ‘open circuit’ on the test meter. In these cases I can use the good coil as a reference to what the faulty coil should be. It had a dc resistance of 7.61 KOhms. Wiki told me the final dc resistance of the whole pickup is approx. 13KOhms so that gave me a pretty good indication of how I should wind it. That’s a powerful set of coils to go with that magnet.

A bit of maths, plenty of experience and some intuition and I had a plan for winding it. Detailed information just isn’t available for this kind of job.

humbucker bobbin

I stripped the bobbin and wound the coil.

pole pieces

I potted it very lightly because these bobbins are made of butyrate that has a lower melting point than most modern ABS bobbins – I didn’t want it to deform with the heat, I wasn’t going to be able to get another bobbin.

Here you can see the chunky pole pieces, they’ll guide a fair bit of that ceramic magnet’s strength up to the strings.

Fender Lead I Pickup

If you have a faulty pickup or are interested in my range of handmade pickups have a look at the website

https://mrglynspickups.com/

https://www.youtube.com/c/MrGlynsPickups/videos

Mr Glyn's Pickups Roboguy

Tuesday 20 September 2016

Stratocaster Pickup re-wind.


A customer brought me a 'dead' Strat style pickup the other day. It's out of an 80's Yamaha but its identical to a Fender in design.


Mr Glyns Pickups

I see quite a few old Fender pickups that have suddenly started to sound thin and quiet. It's a common problem, the insulation breaks down over time shorting out the pickup. 

The fate of this pickup was sealed when it's owner decided to adjust the pole piece height. It has the vintage style staggered poles, they are not adjustable, if you push them in it will sheer of a load of wires and kill the pickup. 


Strat Pickup Mr Glyns Pickups

I like pickups, I like rewinding them. It's such simple high school physics but so fundamental to electric guitars.
 A pickup is simply a magnet with a coil of very thin wire wrapped around it. If you pass something ferrous through the magnetic field (a vibrating string) it disturbs the field causing electrons in the coil to move - that' electricity. It's not much electricity but amplify it a couple of times and you've got stadium ROCK. Cool eh.
To make a pickup sound good is rather more complicated, in fact, rather surprisingly so considering the basic principle is straight forward.

I tested the pickup and the meter showed it was dead. Before snipping all the windings off I just re-solder the wire terminals just in case of dry joints, this does sometimes fix it , worth a go.



Mr Glyns Pickups


In order to re-wind it I need to cut off the old windings. The wire is as fine as hair (I'm judging by my own) and there are thousands of turns of it. I'm careful not to damage the bobbin while doing this. Any little nicks can catch on the new windings and ruin an otherwise good rewind.


Mr Glyns Pickups


Mr Glyns Pickups

The old windings are off now and you can see what happened.
The two highest pole pieces that were pushed down have torn the protective tape and sneered off some of the turns.


Mr Glyns Pickups

You can see what a simple structure a Fender pickup is. Each of the 6 lugs is an alnico magnet press fitted into vulcanised fibre board. I use a blade to scrape off any excess wax and smooth out any high points.

Mr Glyns Pickups

 I seep very thin superglue into the magnet/fibreboard joints just to be sure it's all still strong.

Mr Glyns Pickups

I replace the tape with some thinner stuff. The tape increases the life of a pickup by preventing the inner windings from shorting out on the pole piece. I use really thin tape to keep the inner windings as close as possible to the magnet. There's a lot of high end clarity that comes from these inner windings. This pickup is ready for the winding machine.

Mr Glyns Pickups


Mr Glyns Pickups - winding machine

I mount the pickup to the machine with an extra little block to keep the underside straight. Some vintage pickups can get a bit bendy without this support when winding.

Mr Glyns Pickups

I anchor the wire by wrapping it through the lug 4 or 5 times.


Mr Glyns Pickups

 I prefer to wind with a combination of scatter winding by hand and machine winding. I've tried so many different ways over the last 20 years, this works best for me.
Here's the finished coil. You can see it looks slightly uneven, that's intentional. If you wind a pickup too neatly it sounds a bit dull. An element of randomness creates a loose, open clarity. 

Mr Glyns Pickups coil winding

I've wound this one with 8500 turns of 42AWG wire. It's come out at 6.2 KOhms which was about what I wanted. This is a bridge pickup and the other two are 5.6KOhms wound with the same gauge wire. So it should match in well.

I wax pot it to prevent micro phonic feedback

Mr Glyns Pickups pickups potting

 And we're done - this Strat pickup lives to ROCK another day

Mr Glyns Pickups Strat re-wind

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Feel free to contact me, mrglynspickps@gmail.com




Tuesday 16 November 2010

Hofner Pickup re-wind

I had a visit from Paul Crowther the other day (always a pleasure to see him). He's rather a legend for amongst other things his 'Hotcake' overdrive pedals and the 'Prunes and Custard' (my favorite for theremin).

http://en.wikipedia.org/wiki/Emlyn_Crowther

 He wanted to know if my coil winding machine was up and running -  he had an interesting pickup for me to wind.


 Its an old Hofner pickup which I guess is from the 50's. The guitar has 3 of them and this one has a break in the windings so needs to be re-wound.
This would normally be a straight forward job except for the design of this pickup.


 This is the inside of it. The windings (around the outside) are not wrapped around a bobbin. They are just sitting in the pickup and have been wrapped in tape to protect them. In the middle you can see the magnets sitting in a hard putty. There are incidentally only 5 magnets.
 So the problem Paul left me with was how to wrap about 5000 turns of extremely thin wire into a coil and therefore make a pickup.
 After a long brainstorming session with Sheena we came up with a plan.

 We figured that the wire had to be wound around a bobbin and then somehow the bobbin removed.



 So I made this bobbin. The sides are plastic from a Strat pickguard (white) and the centre has been carved from candle wax.



The bobbin bolts together and is attached to another plastic plate which in turn fits to the winding machine.
 The idea is to wind the pickup on this and then warm the completed coil up and melt the wax. The wax should seep into the coil thus potting it as well. Then the sides can be unbolted and voila a copy of the original coil.


 Winding the coil wasn't any different from any other pickup - so now for the tricky bit.


 I warm the coil ever so gently with a heat gun. I put my free hand next to the work to judge the temperature - if it gets too hot the plastic will melt and I'll be starting again.



 When I see some wax oozing out I ever so gently remove the top plate.



 With the wax exposed I can apply more heat and watch it flow into the coil and as it cools becomes solid.



Then I wrap tape around it to hold everything in place. I cannot emphasize enough how fiddly this is. There are a few stray wires and if any of them break I'm starting again.


It may not be much to look at but its taken hours. The slight curve is to match the shape of the pickup casing. I've tested it and I'm pleased with it at 5.5Kohms.
 In the background you can see the magnetic lugs - I had to dig them out of the putty.


 I put the whole thing back together using 'friendly plastic' instead of putty then fill the casing with wax, solder the back on and its finished.

 Its been quite a task but I'm happy with the result.

   Glyn



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