I know next to nothing about electronics but I'm assuming it's a bad earth...
I've taken the backplate off and there's nothing that appears disconnected, I also took the bridge off and the earth is in place...
I can't find a schematic for it, but the config is the same as a Fender Jazz...
I know this is a bit unscientific, but does anything look obviously out of place?
![Image](http://homepage.ntlworld.com/c.walker25/bass.jpg)