I opened it up (Fig. 1), expecting just to bend the jack so it holds the plug tighter. I did that, but the problem persisted when I wiggled the cable. Looking more closely, it appeared as though the ring part of the jack was too big for the plug. I tried another cable to be sure the one I was using wasn't slightly small. Same issue.
|Figure 1. A little too much space between the ring and the plug. And how about that top notch shielding?|
So I just replaced the jack with a better one (Fig. 2). The plug fit perfectly, and no amount of wiggling made the noise cut out. I don't know what brand the jack is—I had a bunch on hand—but it was noticeably more solid and well-made than the stock jack. (If you're unsure, you can't go wrong with Switchcraft, sold pretty much everywhere.)
|Figure 2. Crap jack on the left, and the newly installed and visibly much sturdier jack on the right.|
With such a cheap bass, I figured it's a good idea to check out everything else too, while I've got it apart. I cleaned the pots and checked all of the connections (looked good). You can always replace the electronics wholesale while you're at it, but this is a cheap bass that I use only occasionally, so it's good enough now.
|Figure 3. Silvertone LB11 bass.|