A while back, I helped one of my (guitar player), customers fix his rock saw, and I wouldn't take his money. A couple days later he gave me a Blues Junior that he used to use, no speaker, no tank, and filthy. Said it was working fine, and then the second set, the "bottom dropped out". I took it home, and connected a speaker, and played my Tele through it for a while, and decided to get the SG, and try it. When I touched the cord, it made all kinds of racket, (I had heard that the plastic jack was really a problem on these!)
Replacing the jack is a piece of cake, the chassis hole is the correct size for a Switchcraft isolating washer, so it is now permanently fixed.
I can't get over why Fender would use such cheesy parts, (cheap plastic jack, and the pots are tiny, and not attached to the chassis at all!) I really can't see how they justify the price they get for them!