Passive tone control malfunction - help needed please!?

Discussion in 'Pickups & Electronics [BG]' started by Fender32, Jul 5, 2008.

  1. I'm afraid that I'm a bit of a dunce where anything electrical is concerned, so I'm throwing myself on your (collective) mercy here :p.

    I have just accquired a 1986 Westone Spectrum GT bass, which has two pickups (one "P" style and one "double J" style), a three-way selector switch, a master volume and front and rear passive tone controls.


    Everything works as it should, except for the tone control for the rear pickup ...


    When I roll off the treble, it acts exactly as a volume control and simply fades out the signal :meh:.

    I guess that it's a problem with the capcitor or the pot, but I'm really not sure. Could it also be a problem with a short in the pickup windings (I seem to remember a similar issue with a Jazz Bass pickup that I had, which needed re-winding :meh:)?

    Here's the wiring layout in the control cavitiy:


    So, any advice please :)?
  2. Alcyon


    Jan 15, 2008
    Vancouver, BC
    ooohhh. pretty. but i am totally useless.
  3. Not entirely, Alcyon ;). You've just made me feel even more proud of my new (faulty) bass :p.

    Thanks! :smug:
  4. Rune Bivrin

    Rune Bivrin Supporting Member

    Oct 2, 2006
    Huddinge, Sweden
    Start by taking a piece of wire to short out the capacitor. If that doesn't change the behaviour it's likely the capacitor is shorted.
  5. So, I took the rear cover off today and plugged the bass in to test out the function of the tone pot. I had a little poke around the wires to look for broken connections etc., but saw nothing odd.

    To my surpise, it worked!

    Then, when I flipped the bass back over to screw the cover on, a little blob of dried solder fell out :meh:. As I said, I'm a dunce with these things, but I assume that this solder blob must have been wedged in somewhere, causing a short on the tone pot :confused:. Does that sound likely?

    Anyway, it's all OK now and I didn't even get my hands dirty!

    Thanks a lot to evreyone who replied, or even just read my post and gave it some thought.