Strat Pickup Magnet discharged!!

Discussion in 'Luthier's Corner: Guitar & Bass Technical Discussi' started by RvChevron, Jul 8, 2005.

  1. RvChevron

    RvChevron Member

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    I bought a brand new Dimarzio HS-2 to try out for the bridge position.

    The low A string was noticeably weaker in both volume and highend response.

    I tapped the lOW a pole with a screw driver, sure enough, it has no suction/magnet pull whatsoever compared to the rest of the pole.

    Being the last one they had, the store took it back and was going to get Dimarzio to exchange another one for me.

    *****They then called me saying "I" might have done something wrong that caused the low A pole to have no magnet pull.******

    Dimarzio will recharged the magnet for me, I haven't asked the store if they're doing it under warranty.

    I've been working on guitar electronics and swapping pu's for more than 12 years and had over 100 pu;s, I have never encountered a strat pickup with just one of its pole to be dead.

    Anyone has any idea as to why the low A pole or any pole on a strat pickup to have no magnetic pull?

    Thanks!!!
     
  2. alderbody

    alderbody Member

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    >>Anyone has any idea as to why the low A pole or any pole on a strat pickup to have no magnetic pull?


    ...because it never had!!!...

    IMHO, Dimarzio must have put an unmagnetized polepiece in there by mistake.
    Also, "being the last one they had" might raise some suspicions...

    Demagnetizing a p/p in that extent is not something that can be done when the p/p is mounted on the bobbin... At least without damaging the rest of the pickup...

    i think that they are BSing you!!! :mad:
     
  3. Taller

    Taller Silver Supporting Member

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    Anywhere is everywhere and nowhere is nothing.
    Indeed. How in the world does someone go about causing a magnet to 'de-magnetize'? I mean, if you really wanted to do that.
    And if it could be done, one would think that a single pole couldn't be isolated from the other poles, i.e. other polepieces immediately next to the 'dead' pole would have to have been affected.

    Recharge? They should replace the pickup without question.:mad:
     
  4. alderbody

    alderbody Member

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    There are a few things you can do to demagnetize a magnet, but it cannot be done on a single polepiece without affecting the others too...

    Heat and an opposing magnetic field are two of them, but it takes a whole procedure.

    There is a certain temperature limit that you have to exeed and blah blah...

    anyway, the guys at the shop are definately suspicious...

    why don't you contact DiMarzio? ...and give them a note about their dealers in Hong Kong?.... ;)
     
  5. John Phillips

    John Phillips Member

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    Some magnetic materials can be demagnetized by very severe shock (impact), but I still doubt you could do it to just one pole.

    I had a Seymour Duncan Strat pickup new out of the box with two dead poles once - the top two strings. It really baffled me for ages why I couldn't get the string balance right, until I tapped the poles individually.

    That's the only one I've ever come across. They must just have had a quantity of poles that missed the magnetizing process somehow. I can't understand how they would make it into a pickup though, since the assembly worker must have to check the magnetic polarity to make sure it's the right way round.

    Weird.
     
  6. alderbody

    alderbody Member

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    I 've read somewhere that this might be a myth...

    But i guess the one who wrote it was trying to keep guitarists from throwing their pickups to the ground in order to make them more "vintage sounding"... :D
     
  7. Mark Robinson

    Mark Robinson Gold Supporting Member

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    It's possible to de-gauss a magnet with one of those huge Weller soldering pistols with the huge transformer right in the gun. That would probably be a bit more of a global event, however, not confined to a single magnet in the ranks. :)
     
  8. alderbody

    alderbody Member

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    The fact is that with a normal 40W soldering iron you get a max temperature of about 300-450 degrees Celcius. (centigrade)
    If you want to permanently demag an AlNiCo magnet,
    you should heat it up to, or exceed 860 Celcius.

    i have done something like that once with a set of pickups i had as a test set
    (which btw i use now in a strat...)

    What i mean is that with a 40 Watter, all i did was to demag the polepieces for a few minutes.
    I remember that when the p/p was still hot it had no magnetic pull, which got back after cooling.
    I'm not sure if the returning magnetic pull was the same as before, but what i must have really achieved was a 'stabilisation' of the magnets, thus a more constant flux in future temp variations.
    (i don't really recommed it, especially for pickups with plastic bobbins...)


    But i guess that with a ..."high-gain":)D) soldering iron one can get that threshold temperature
    (Curie Temperature) and kill the magnets... (but also melt or burn the bobbin...)
     
  9. John Phillips

    John Phillips Member

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    It can be done with 'soft' iron... I remember doing it as a physics experiment when I was a kid. Magnetize a lump of iron, then hammer the **** out of it on a bench anvil - it does demagnetize it.

    But I very much doubt that the strong permanent alnico magnets that polepieces are could be affected by any amount of force that wouldn't simply destroy the pickup - or by heat, for the same reason. It must be something that happened at manufacture. I'm still puzzled how though...
     
  10. alderbody

    alderbody Member

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    I just took a wild guess, John....

    Maybe after assembly, that polepiece was somehow not very well fit in the base or the flatwork.
    So someone might have taken a hammer and a screwdriver and hit the stray polepiece to make it fit...

    (obviously ignoring what would happen to the p/p itself or the coil around it...)

    anyway, s**t happens... :D
     
  11. RvChevron

    RvChevron Member

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    Got a reply from Dimarzio. They received the pickup today.

    They said in 30 years of business, they only found two defective magnets in their pickups.

    The second one was in my pickup.

    They replaced the magnet and will be sending me a free white strap.

    Problem solved!

    I hope they won't find their "first strand of defective nylon" in the strap they are sending me!:D
     
  12. VanWayward

    VanWayward Member

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    i have the same problem in one my pickups both the high e and g in bridge wont work.
    im kind of worried of since i paid $300. they are rocketfires. i really love how they sound but i wish the pole pieces would work
     
  13. walterw

    walterw Gold Supporting Member

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    zombie thread wants braaaaiiinnss!

    for $300, those things better be perfect! i'd send them back.
     
  14. Phostenix

    Phostenix Member

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    Is there a statue of limitations on these things?
     
  15. Ronsonic

    Ronsonic Member

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    Zombie thread never dies.
     
  16. VanWayward

    VanWayward Member

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    i emailed the guy and he told me how to re-magnetize them luckily i had jus the tools i needed to re-magnetize them .i took a super strong/big neodium magnet (that I just happened to have lying around) and rubbed them for a few minutes against the top of each pickup then against the back keeping the same side of the magnet up, and tada! they all had magnetic charge.

    But I wonder if there is anything I could have done to them to demagnetize them. all that I did was use a low power magnet to test the direction of each pickup, could that have been?
     
  17. ShavenYak

    ShavenYak Member

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    No, but there is a statute of limitations.

    The statue of limitations was never finished because no sculptor could really come up with a visual representation of the abstract concept of limitations.
     
  18. walterw

    walterw Gold Supporting Member

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    [politics]any statue of a dictator could be called a "statue of limitations" since it represents the oppression of his people.[/politics]
     

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