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Need some advice on a miswire...

Discussion in 'Pickups & Electronics [BG]' started by Verticos, Oct 3, 2009.

  1. Verticos


    Mar 29, 2007
    Boston, MA
    So, my Fender Jazz 24 is no longer functioning. About 9 months ago I wired it up with an Aguilar OBP-3, and everything worked fine and dandy. Fast forward to now. I was replacing the push/pull volume pot because the old one was broken. I wired it all up, and lo and behold, the pickups no longer work when the blend is centered. I am no expert at wiring electronics, and I am under the opinion that my retrofitting of the Aggie only worked correctly by sheer luck. :ninja: I am sure this is because I wired something wrong putting it back together.

    With the blend centered, I get zero output from the bass, and a lot of hum and radio interference. The bass works fine with either of the pickups solo, but conks out when I try to blend them. I tried rewiring the blend pot, so now I am sure that the blend and the volume are both wired correctly.

    I could find very little on the internet about other people with this same problem. The closest thing I could find was someone saying that if the pickups were out of phase, the volume would sharply decrease when the blend was centered, but nobody ever complained about a complete loss of volume.

    Any advice or things to try and correct this are greatly appreciated, as I have a gig to play this week and I would very much like to use this bass...
  2. Before we can tell you what you did wrong, you're going to have to elaborate on the wiring job you did.
    Can you take pictures or something?
  3. Verticos


    Mar 29, 2007
    Boston, MA
    Alright, today I totally checked the whole wiring setup as according to this diagram. (the same diagram I wired it with before, when it worked)


    Everything checks. It should work. But I am still getting a loss of volume and a large amount of static when the blend pot is at the center detent.

    I also checked the other electronics, and everything works when I have either pickup solo'd. All of the EQ works, the volume does it's job, and so does the push pull on the volume that was the purpose of this little excursion.

    Due to the fact that all of the pots are doing their job except for the blend, I am assuming it's either the blend pot, the pickups, or a grounding issue.

    Pickups are my area of least expertise in wiring. I have the outputs of each pickup wired to their respective lugs on the blend pots, and the grounds are grounded onto the sheilding on the side of the cavity, which worked fine before. Check.

    The blend pot is definitely wired correctly, so that's not the problem either.

    So, I'm stumped. I don't know how much help pictures would be, it's a jumbled mess of wires anyway... (I didn't really pay attention to organization while I wired it... :meh:)

    But if you need pictures, I will post them soon.
  4. M0ses


    Sep 11, 2009
    Los Angeles
    I'm just guessing here, but maybe the blend pot is defective in some way?
  5. Verticos


    Mar 29, 2007
    Boston, MA
    Nope, the blend pot is fine. It is the same blend pot I used before I made this mess. The only thing that has changed since it worked has been the push/pull volume pot.


    I took the bass and plugged it into an amp, again, but this time, I fiddled with the wires and just arranged them and jumbled them up while I was testing it.

    It is definitely a grounding / short issue. I could get the signal to magically appear, but only when the wires were jumbled in just the right manner. Same thing here as what you do with a frayed cable. Finagle it a bit, and it works.

    So, now I am meticulously checking for shorting wires or any grounding issues. Hopefully I can find whatever is shorting tonight, because I have a gig tomorrow and I would really like to use this bass...

    Stay tuned.
  6. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Check to see if you didn't wire up the blend with the hot and grounds swapped. Also check to see that the ground is intact.

    That's what it sounds like to me.

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