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Circuit testing

Discussion in 'Luthier's Corner' started by mahrous, Feb 21, 2006.

  1. mahrous


    Aug 13, 2005
    ok, so i am wiring my second bass but for some odd reason no sound comes out.

    this is the simple Jazz wiring schematic V/V/T. I have used it many times before and it worked from the first time. this time its not working. no sound whatsoever whether hum or buzz.

    the only thing i can think of is that it has bad pots (bought from Stewmac). How do i test and find out which pot is not working correctly and all that? yes, i have a multimeter for resistence, current, circuit testing and all that.

    thank you!
  2. luknfur


    Jan 14, 2004

    Digital meter have no clue. For one with a swing arm, just put alligator clips to the center and outside pot lugs and clip the other ends to the meter probes, put the meter on RX1K, and rotate the pot. If the swing arm moves in accord with the stem rotation, it works. If it doesn't, you've probably got a bad meter connection. Chances of more than one pot being bad at once is a long shot. Then swap the outside lead over to the other lug and repeat to test all 3 lugs. Do that on each pot.

    The high probability shot is flawed wiring.

    In my recall, you were also making your own pups. If these are some, do the same thing with the meter on the pup coil start and finish leads with pup wires disconnected from the pots. If you get no arm swing on the meter - pups have a short.
  3. bill h

    bill h

    Aug 31, 2002
    small town MN
    Look for a ground
  4. mahrous


    Aug 13, 2005
    i highly doubt its flawed wiring. i have wired many basses before using this exact same schematic. i have matched in reality to my other bass that i wired last week. identical wiring techniques and all.

    i got no swing arm :( any other suggestions before i start removing solders and do trial and error?
  5. luknfur


    Jan 14, 2004

    I've wired plenty myself yet do it all the time. This is not the bass you wired before, apparently that one works, this one doesn't. If you get no swing on pots, they don't work - or you have a bad connection. If you just touch the meter probes together and the arms don't swing, then the meter's not working (unless the meter is incorrectly set). If they do, it is.

    It's possible more than one pot is bad, just highly unlikely.

    If there's one thing you don't want to do in trouble shooting, it's assume anything. Everything is wrong to demonstrated to be otherwise. Otherwise you're not trouble shooting, you're guessing at random.
  6. Audere

    Audere Supporting Member Commercial User

    Apr 7, 2005
    South Beach, OR
    Owner: Audere Audio
  7. Geoff St. Germaine

    Geoff St. Germaine Commercial User

    Test your pots.