I have a set of DiMarzio DP126 PJ pickups that I just migrated back to a bass that had some SD QPs in it that I didn't like. Usually the DiMarzio pickups are dead quiet, but now that they are back in this bass I am having a grounding buzz issue. If the bass just sits on my lap, there is a faint buzz, but if I touch the metal parts of the bass it stops. I've re-soldered the grounding wired from the pickups three times now, so I don't think that is it. There seems to be a lack of how-to walkthroughs for finding exactly where the ground problem is happening on the internet. It is an all passive bass, set up Vol Vol Tone, with a on\off switch for the P and J. The buzz stops if I touch the strings, tuners, bridge, and knobs, but not if I touch the switches, and it buzzes a little more if I touch the pole pieces while not touching anything else. There must be a way to use a multi-meter to check the electronics of a bass for proper grounds. Can someone please help me with this? Update: Allow me to clarify something: These pickups were completely silent in this bass a few months ago and in another bass just moments before I removed them. They are humbucking. I either installed them wrong or damaged something. This is not a typical 60 cycle hum\RF problem. I am looking for advice on how to determine what I did wrong and correct it.