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Extremely weak signal/ Precision bass

Discussion in 'Pickups & Electronics [BG]' started by steven welborn, Dec 4, 2018.

  1. steven welborn

    steven welborn

    Dec 4, 2018
    Hello. First time post here. Not sure if this forum is the place to ask. I have a 2013 Precision bass (USA) which is putting out very weak signal. Patch cords and amp have been eliminated. It's definitely in the bass electronics. Anyone here advise the best steps to troubleshoot the culprit? Or suggest who to ask? Thanks!
  2. keyboardguy

    keyboardguy Supporting Member

    May 11, 2005
    What is the height of your pickup?
    Generally when you hold down a string on the last fret, you should have 1/8 inch clearance from the actual pickup...
  3. keyboardguy

    keyboardguy Supporting Member

    May 11, 2005
    Oh, and are your strings of a decent brand? Not cheapo ebay imports?
  4. 96tbird

    96tbird PLEASE STAND BY

    I would begin with checking the jack for dirt or corrosion, then for cold solder joints and partially broken wires at the solder joints.
    Last edited: Dec 9, 2018
    Isotonic likes this.
  5. Slater

    Slater Leave that thing alone. Supporting Member

    Apr 17, 2000
    The Great Lakes State
    If you have a multimeter, check the DC resistance of the pickup, and/or wire the pickup directly to the output jack.
    96tbird likes this.
  6. Isotonic


    Oct 19, 2011
    Round Rock TX
    Open up the cavity and put a ring of electrical tape around the input jack. While you are in there look for any disconnected wires.
  7. steven welborn

    steven welborn

    Dec 4, 2018
    It is definitely not pickup height or old strings. Will check all the possible culprits suggested i.e. cold solder joints, corrosion, etc. Should'nt be anything with the pickups themselves though this being a 5 year old usa Fender P bass. Will check the dc resistance of the p'ups though. Anyone know what resistance should be?
  8. 96tbird

    96tbird PLEASE STAND BY

    8-10 komhs

    Edit: or higher. Just as long as they’re in that ballpark, they’re fine. If they’re dead (internally broken wire) they’ll go off the scale. That’s all you need to know.
    Last edited: Dec 10, 2018
  9. Slater

    Slater Leave that thing alone. Supporting Member

    Apr 17, 2000
    The Great Lakes State
    10k - 11k
  10. Indiana Mike

    Indiana Mike Supporting Member

    Nov 18, 2005

    Bad volume pot?
  11. steven welborn

    steven welborn

    Dec 4, 2018
    I de-soldered both wires to isolate the pickups and I get a reading between 260-280 K fluctuates kind of wildly between those values. Something tells me that sucks. First I de-soldered the one black wire attached to the pot casing leaving the yellow wire attached to pot terminal and got about 22K. Then detached that wire then got the 260-280K.
  12. voided3

    voided3 Supporting Member

    Nov 11, 2008
    On my P-bass, I ended up routing the control cavity slightly larger around the output jack because the clearance is so tight and my cavities are shielded. The positive lug of the jack would short against the shielding when assembled, even though I had put heat shrink on the majority of the terminal.

    I would check that you have good ground continuity first between all ground points, then check that the lugs of the potentiometers and the tone cap aren’t touching ground or each other. I’d also check that the bottoms of the pickups aren’t shorting on any shielding. Since they are two coils in series, any contact with ground will likely short them.

    Worst case scenario, as long as the pickup is good, a P-bass is one of the least expensive instruments to rewire from scratch as there are so few components. You could even save yourself a little work, but spend a little more, and get a pre-wired Emerson harness to drop in.
  13. steven welborn

    steven welborn

    Dec 4, 2018
    I'm judging from the resistance reading the pickup has bit the dust for some reason. Im not that up to speed on replacement P-bass pickups. Did some quick research and sounds like the P46 or J45 are popular and might be an upgrade from stock to boot. Much difference between the two or other recommendations?
  14. 96tbird

    96tbird PLEASE STAND BY

    J45 is a jazz pickup. Won’t fit in a P without beavering out some wood.

    I have a p46 in a Squier P. Great pickup. You’ll likley need to do some light filing on your pickguard to make it fit though; mine was a bit snug and the screw ears were larger than the pg but it was a Chinese ebay pg so... but the stock pickup fit fine on the guard. The case of the pickup is just a bit bigger than normal.

    Great points are that the magnets are grounded internally (blue wires go to ground) which not many makers do. They are epoxy potted so basically indestructible. Also, the jumper wires between halves are separated so you can wire it to a switch for series or parallel selection, or just solder them together for normal series install.

    Really powerful clean pickup.

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