Question about Duncan Designed JB101 pickup wiring - please help.

Discussion in 'Pickups & Electronics [BG]' started by BluesOnBass, Mar 8, 2014.

  1. I recently purchased a Squier VM Jazz Bass in mint condition, except for the bridge pup not working. I got it for a great price and figured there was a loose wire. The original owner never learned to play it so was just wanting a bit of cash. Anyway, I open it up and no loose wires. But comparing it to the Duncan website diagrams, it is not wired at all the same. Also, all the diagrams show two wires coming off the pups, but these have three - one white, and two black. I am figuring maybe the other black is a ground of some kind? So far I am not having any luck getting that bridge pup to make a noise of any kind. I have not rearranged all the wiring to match the diagram yet, but I thought maybe someone else has run into this and could give me some guidance about the three wires before I do any more rearranging of wiring.

    This guy I bought it from did not seem the type to have messed around with it, but who knows. I am surprised the wiring is so different from what Duncan shows for those pups.

    Any thoughts or tips would be appreciated. I did do a search on here and through Google, and am coming up with only two wire diagrams.

  2. Wow. First time I have asked a question here and got nothing. I figured these pups are pretty common out there and somebody would know what the three wires are for. I find four-wire and two-wire diagrams, but no three-wire. Huh. I guess I will continue researching and hope I come across something helpful. Probably will be good to get more tools at some point so I can measure continuity etc. However, if anyone has any helpful ideas....

  3. Three wire pickups are common. The third wire is usually a shield.
  4. Thanks. It appears to be a ground to the body, so I have essentially three ground wires to the body. Trying to make sense of if I can just tape these off or they need to connect to spots on the pots. I have tried a few different things and still neck pup works, bridge does not. Am wondering if I have either a dead pot or pickup. Probably pot if anything. I don't have a spare around so I'll order one. Can always use it in something else if it turns out this one is really ok.
  5. Cadfael


    Jan 4, 2013
    Germany, EU
    The wiring diagram is in my 485 pages bass compilation (no. 1.2.333) ...

    Yes, the "second black" wire is shielding/gnd under the pickup.
    Solder it/them/all black wires to the PU housing.

    The wiring of the tone pot may differ from the SD page - but there are many ways to wire a tone pot correctly. The cap is wired to the tone pot housing and the middle contact? One contact of the tone pot is wired to "tip of the jack" and then goes to the "left contacts" of the volume pots?

    My wiring diagram is at the end of this page:
    Scroll down and click "Bassschaltungen409.pdf" (might be have a higher number in future!). It takes a bit until the 7.6 MB are loaded. In version 409 you find drawing 1.2.333 on page 84 (page might differ in future) ...

    If bridge PU doesn't work at all: Multimeter would be best ...
    Solder the white wire directly to "HOT of the jack". Solder both black wires directly to "GND of the jack. Does it work now???

    Photos ot the control plate would help a lot ...
  6. Thanks for your response Cadfael! I was actually at your website yesterday, did print out page 84 and used it to compare to the wiring in my bass. I found a reference to it in another thread. Thank you so much for all the work you put into your guide!!

    Are you suggesting that I connect the two black ground wires from the area of each pickup to the input jack? If so, that's worth a try as nothing else is working so far. I really think I have a dead pot. As an aside- it sure takes a long time to melt the solder on the pots!

    I will post what I find out to be the solution when I figure it out. Thanks again for your response and for the guide you have made!
  7. I can post some photos, but I keep changing it to see what might work - at least as far as the bridge pot goes. The neck pot I am leaving alone as it works.
  8. Cadfael


    Jan 4, 2013
    Germany, EU
    You could de-solder the not-working bridge PU and see if it works with a multimeter. Maybe one of your neighbours owns one???
    If not, you can solder the PU directly to a jack and see/hear if there's a signal.

    You could only solder the black PU wire to GND of the jack. If you are not sure which one the PU black and which one the shielding black is, solder both to GND of the jack.

    If the Pu works, the fault must be somewhere else.
    If it doesn't work, the next question is: Why?
  9. Thank you. I will do that next.