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how to quick-check if the pickup is working or not

Discussion in 'Pickups & Electronics [BG]' started by iuserneim, Apr 14, 2012.

  1. Apr 14, 2012 #1
    iuserneim

    iuserneim

    Feb 7, 2009
    germany
    hey folks.

    got a used bass, and here's the situation:
    the bridge pickup is working fine, but the neck pickup doesn't produce any sounds.

    it's an active bass.

    now, is there a way to quick-check, if the pickup is ok, or whats wrong ?

    i guess, the voltage from the pickup is too low to measure it while plucking the strings, right ?
    i thought about measuring the resistance/conductance of the pickup, where it's going into the balance-pot. if there is conductivity, i guess it's all right ?

    but since the electronics of this bass is really way more complicated than the other preamps i worked with, and there is no hint of any kind, what all the cables of the preamp are for, maybe there is another, simplier way to find out ?

    thanks in advance...
     
  2. Apr 14, 2012 #2
    bassbenj

    bassbenj

    Aug 11, 2009
    Presumably it's the typical active bass which has passive pickups (no battery leads going to pickups) and a "blend" pot ahead of the preamp. So this means that the preamp wiring is irrelevant.

    Quick and dirty test is a follows. Set blend in middle (detent?) then take a paper clip or small screwdriver and tap on poles or top surface of pickups. Try both the neck and bridge pickup. You are supposed to hear a pretty loud click from each pickup.

    If you don't then the silent pickup has a problem.

    If you do hear both clicks then try the balance control one way max and then the other way. In each case only one pickup should be heard. If one pickup quits when maxed on balance control then it is likely the balance pot is bad and needs replaced. If one pickup is ALWAYS dead no matter what, then problem could be pickup, wiring, or balance pot.

    To test pickup, you must unsolder the pickup "hot" wire from the balance pot and measure resistance of the pickup to ground. (the other wire). If it measures "open" which means very high resistance, then it's likely a broken wire in the pickup and it will need be rewound or replaced. But if resistance measures zero, then it's shorted and also will need replaced. If it measures normal values, then the pickup is probably OK but wiring or balance pot has a problem.

    That's about it for quick and dirty.
     
  3. Apr 15, 2012 #3
    iuserneim

    iuserneim

    Feb 7, 2009
    germany
    I can't hear a click when i tap the pickups (yes, they are passive bartolinis).

    so, i gotta unsolder the pickup and check the restistance.
    shorted or broken wire is ok. but what should be the "normal" resistance of a bartolini single coil ?
     
  4. Apr 15, 2012 #4
    iuserneim

    iuserneim

    Feb 7, 2009
    germany
    my soldering iron doesn't work anymore.
    can i check the resistance of the neck pickup by turning the balance pot all the way to the bridge pickup ?

    if i'm not wrong, when turned all the way to the bridge PU, the balance pot has a large resistance for the neck PU, but it's not grounded... right ?

    anyway, i think, measuring it the way i just said, it should give different results for a broken pickup or a working pickup. no ?
     
  5. Apr 16, 2012 #5
    bassbenj

    bassbenj

    Aug 11, 2009
    Yes for quick and dirty you should be able to measure it wired in. It depends on the wiring though. Since both pickups are wired to the blend control it's hard to get a reading on a single pickup. This is why disconnecting them is best. On the other hand if a pickup is shorted you should be able to read that even with the blend control still in place. Be sure to turn the pot while taking readings because in usual wiring the blend pots short the pickups to control volume. So for some positions the pickup may appear shorted but it's really just the pot shorting it out to control volume. Best is to just disconnect the pickups so you don't have to worry about what the pots are doing.