Hotspots to check for bad ground on bass?

Discussion in 'Basses [BG]' started by Mike A, May 16, 2003.

  1. Mike A

    Mike A Supporting Member

    Oct 3, 2002
    Just received a Pbass from someone that has a bit of a grounding problem somewhere... light to moderate hum. (FYI.. Problem was well known before the sale, no issues there. )

    Here's what I do know about it: Bridge ground wire isn't soldered, but it is locked in contact with bare metal on the bridge. Bass hums very little when nothing is touching it, hums LOUDLY when touching only the pickup mounting screws, and STOPS humming when the bridge is touched (with fingers, in both cases.)

    Help an electronics noob out a bit!

    Also.. any tips on soldering the ground to the (black) bridge? I tried many times (after stripping a spot on the underside to bare metal and heating the bridge waaay too hot to touch...) I gave up after a while and stripped the finish off the inside of the middle mounting screw hole and pulled the bare wire up through it, then locked it down with the mounting screw.
  2. JOME77

    JOME77 Supporting Member

    Aug 18, 2002
    Soldering the ground wire to the bridge isn't required. Just strip off enough insulation to double up the bare wire and maybe move it to a fresh place under the bridge (make sure that the bottom of the bridge that will contact the bare wire is roughed up a bit to assure continuity. Then you can check and make sure that each component is straped to ground. Some mfr's install a piece of metal foil and connect the various pots and sw's connect via the foil or a metal plate. The problem with this is that when a pot or switch get's loose, you develop intermittent grounding problems. Solder a wire from component to component. You can check for a good ground to all components and bridge using a VOM (Ohm Meter). Anything beyond this will require a tech to trouble shoot your instrument. It could be a bad PU or the output jack could be wired incorrectly....