4003 Treble pup: moving the bobbin+magnet?

Setup, repair and restoration of Rickenbacker Instruments

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4003 Treble pup: moving the bobbin+magnet?

Postby (espidog) » Sat Jun 06, 2020 11:55 am

This is probably something that falls into the "Why bother?" category, but FWIW...humour me. :wink:

I own a 2004 4003 JetGlo. The treble pup has the non-adjustable staple-type pole pieces of that era.

The bass sounds just fine, but it's always slightly irked me that the bobbin of the treble pup isn't positioned precisely under the strings. You can see what I mean from this rather grainy photo:

Image

The E string is the only one that's dead centre of its pole piece. The other three are slightly to the "south" of their respective strings. We're only talking about 2mm off, but it bugs me.

I'm aware that someone else might say "No, Ken - it's the bridge saddles that're the problem: they haven't been filed in the right places to make the strings match up with the pickup poles" ...but the strings are all the right distances apart from each other and they sit nicely central on the neck, so I don't want to mess with that.

What I'd like to know is this: is it possible (without causing irreparable damage) to remove the bobbin/magnet assembly from the underlying plastic mounting bar and re-seat it ...or am I just asking for trouble even wanting to try? All wisdom gratefully received! :)
2004 4003 JetGlo
Epiphone Jack Casady
Ovation Magnum 1
Mania VTB-4BS
Dean Stylist w/ John Birch Magnum II pups
Yamaha BB414
Trace Elliot VA350/GP11 Mk1
Peavey TB-Raxx
2 BFM Omni 10.5 crossfire cabs
Roland Bass Cube 100
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Re: 4003 Treble pup: moving the bobbin+magnet?

Postby (lumgimfong) » Mon Jun 08, 2020 1:31 am

I replaced all my noisy higains with HB1. .022uf caps. 500k pots.
Just replace it with an HB1 and done. No pole pieces there to torment you.
If you only move the higain then the low E will be off and the torment will perpetuate.
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Re: 4003 Treble pup: moving the bobbin+magnet?

Postby (jdogric12) » Tue Jun 09, 2020 11:42 am

Only 2 things should matter: how does it play? how does it sound? I know, this is no consolation.
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Re: 4003 Treble pup: moving the bobbin+magnet?

Postby (bluewhale) » Fri Jun 12, 2020 5:33 pm

espidog wrote:... "Why bother?"...

Around 1979, I took my 1978 4001 to the factory in Santa Ana to have this corrected. Also the bridge saddles were haphazardly cut, so I had them replaced.

I lived close by at the time. In fact my mother took me there because I was too young to drive. The bass was bought used in 1978, so the work was not done under warranty. They made it right, but I don't know how.

Sorry I can't be of help.
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Re: 4003 Treble pup: moving the bobbin+magnet?

Postby (kiwi) » Thu Jul 02, 2020 11:28 am

Hi,

I'm probably a bit late to join the party, but here's my 2 cents anyway...

The fact that the pole pieces aren't dead center under each string is mainly a cosmetic issue an normally doesn't affect string balance too much. If you still want to correct this, you could try the following:

- uninstall the pickup by loosening the 4 little bezel screws.
- then flip the thing upside down, where the two larger screws secure the PU bobbin to the base plate. Loosen them a bit - if you're lucky there's a bit play between the screws and the screwholes.
- try moving the bobbin to the bass side. Be extra careful not to damage any PU windings! Then tighten the screws again and test-fit the PU.
(- if the pole pieces are still not sufficiently centered, more surgical work is required. Remove the PU from the chrome bezel, unsolder the wire(s) connecting to any soldering lugs on the bottom, and carefully(!) unscrew the bobbin from the base plate. Then widen the screw holes in the direction of the bass side, using a small round file. 1 or 2 mm go a long way. You may apply the same to any PU wire holes. Reassemble the unit and restore all solder connections.)
- reinstall the PU and enjoy the immaculate appearance... ;-)

I can't emphasize enough that one has to be EXTREMELY CAREFUL when it comes to working on pickups! If you're not used to this rather delicate work, better leave it as is...

Cheers & Good luck!
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