I've been getting what sounds like static crackles and pops on my 2012 Gibson Thunderbird. It happens when I run my hands up and down the strings and sometimes when I move the bass in certain directions. The crackling is intermittent but very frequent, and if I run my hands up and down the strings several times and then move the bass around, I can reproduce it. It does not happen when jiggling the output jack, and it happens with various cords and amps. I checked the control cavity, and there does not appear to be any obvious loose connection. On a suggestion I found elsewhere, I tried rubbing dryer sheets over the control cavity cover and rest of the bass, with no results. The control cavity is not shielded at all (not even paint). Also, I'm not sure about the bridge grounding. There is a grounding wire that comes into the control cavity and is soldered to the tone pot housing, but I have no idea where the other end of the wire terminates. Since there is no obvious wire under the bridge, I'm guessing it connects at one of the 3 posts that hold the bridge. Also of note, the original 3-point bridge has been replaced with a Hipshot Supertone that by design does not make contact with the front post. The rest of the bass is stock except for a Hipshot drop-D tuning peg. Any suggestions appreciated.