Ibanez Super 70 pickup problem

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by DW54, Dec 5, 2017 at 8:59 AM.


  1. DW54

    DW54 Member

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    I have an old super 70 pulled from an AS 400 . Thinking about swapping it back in to the neck position to replace the SD jazz I put in there. The problem: Resistance reads only 3.8 K, about half of what it should. It's a 4conductor : ground (bare) red, white and black. Ground and red measure 3.8 K on the multimeter and white and black also measure 3.8K. Do I have a pickup that perhaps has de-magnetized? Could it be repaired?
     
  2. walterw

    walterw Gold Supporting Member

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    no, the magnet has zero to do with the coil resistance.

    sounds like you just have it wired wrong;

    if the "ground" is a bare wire that's also one end of one coil then that obviously has to stay as ground. that means red is what will connect in series to the other coil, either black or white. at that point the leftover wire is the hot. one way will sound thin and also hum, the other will sound right.
     
  3. bigtone23

    bigtone23 Member

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    Is this going back in the AS400? Does it have the Super 70 in the bridge, too?

    I'm not 100% sure, but usually old Ibanez were red positive. Follow walterw's lead first, but also try red as the hot.

    I'm also not sure if this was a 4 wire pickup or 3 plus bare ground for the pickup cover? Many Super 70s were just red hot and braid ground, kind of like old Gibson pickups, but some also have 4 wire hook up. Some Ibanez pickups were 3 wire with hot, ground and the series link wire that went to the coil split push/pull pots.
     
  4. DW54

    DW54 Member

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    So, Walter.With red and black taped together, I'm measuring 7.65K between 'bare' ground and white. White is 'hot'. Am I on the right track?
     
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  5. walterw

    walterw Gold Supporting Member

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    yep!

    if it sounds good and hum-cancels you're there, if it sounds thin and still hums then swap white and black.
     
  6. DW54

    DW54 Member

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    Any way to "test" whether it's thin and humming( or not) without complete installation. Remember : an AS 400 is a 335 type of guitar.Trying to save time and unnecessary effort!
     
  7. walterw

    walterw Gold Supporting Member

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    the hum you can at least test outside the guitar by connecting the pickup straight to an amp; one way will be a lot noisier than the other since the backwards-wired coil will no longer hum-cancel.

    the "thin" part (which is the coil polarity being backwards) is a little trickier.

    if you had a tuning fork and a true strobe tuner it would be easy; activate the fork and hold it over one coil and then the other, if they're in polarity the display will be the same, if they're out it will "flip" the strobe display, the filled-in parts exchanging places with the gaps. (i use a turbo-tuner, its display is a half-circle of LEDs which will flip to the other side if the polarity flips.)

    minus that, you can use the meter set to DC volts and then gently slap down and then lift up a little metal ruler or screwdriver on first one coil than the other; the "drop" will show a voltage spike plus or minus while the "yank" shows a spike of the opposite polarity.

    if both coils show the same polarity on the "drop" (doesn't matter whether that's "both plus" or "both minus") then the two coils are in polarity and you're in business.
     

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