Weird Volume Issue w/ Pawnshop Score (NOW WITH PICS!)

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by The Smith, Jul 19, 2008.

  1. The Smith

    The Smith Supporting Member

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    My wife and I we're in a pawnshop earlier this week, and I came across an '83 Ibanez Roadstar II bass. The thing was way banged up and so grungy, I didn't want to touch it. But it looked both cool and solidly built (MIJ). I got it for $120 out the door, and we took it home and cleaned it all up; it'll be an early birthday present for my wife. It plays like a dream, feels great up and down the neck, but there's one weird issue:

    The volume cuts all the way out only when both the volume AND tone knobs are turned to zero. In other words, with the volume on zero and the tone on ten, a strong signal is still making its way to the amp. There are three knobs total: volume, tone, and blend (there is one P-style and one J-style pickup).

    I've worked a bit inside guitar cavities, but cant figure out what might cause this quirk.

    Any insights would be appreciated.

    Thanks,
    Colin
     
    Last edited: Jul 19, 2008
  2. jefesq

    jefesq Gold Supporting Member

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    pics of cavity might help?
     
  3. bluesjunior

    bluesjunior Member

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    I set up a Bass for one of my sons friends a few years back. I think it was an Ibanez as well. If I remember correctly the pups were active and one of the controls acted like some sort of boost. Like the previous poster says though it would be handier with a pic of the cavity.
     
  4. The Smith

    The Smith Supporting Member

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    Thanks guys,

    I'll upload a pic this afternoon.
     
  5. The Smith

    The Smith Supporting Member

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    Okay, here are some pics. I studied the guts for about 20 minutes and for the life of me, I can't make sense of the circuit.

    [​IMG]
    The above is an overview shot. Notice the cap between the jack and the adjacent pot !? The yellow wire is the hotwire from the neck; the bridge hotwire is wired to the center lug of the center pot.

    [​IMG]
    The above is just a different angle.

    [​IMG]
    The above was what I assumed to be the blend knob, but I'm having my doubts!

    [​IMG]
    Notice the TWO white (horizontal) wires coming out of that lug on the right-hand side. (???)

    [​IMG]
    And the last shot.

    If you can help me decipher this....I'll be your best friend.:eek:
     
  6. Martian

    Martian Member

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    Howdy, best friend, I see your confusion: The way the bass is wired, the upper most pot is for the volume of the 'neck' pickup only, the middle pot for the volume of the 'bridge' pickup only and the lower pot is a master tone, not a blender. The way the bass is wired is so that if you turn down the volume of one pickup, it will not affect the volume of the other and vice versa. Again, the tone pot is a master so it will affect both pickups, regardless of volume. FYI, it is wired (OEM) the same as a Fender Jazz Bass.
     
  7. The Smith

    The Smith Supporting Member

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    You now have an Earthling for a best friend! Of course, once you explained it to me, I looked at the wiring again, and it makes sense. Because I read that these bases have a blend knob, I wouldn't let my mind let go of that concept, and kept trying to figure out which knob it was in vain.

    I learned something today. Thanks a bunch!
     
  8. Martian

    Martian Member

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    Glad to help!
     

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