Lee is pretty much totally right here. In my exp, many cheaper basses from Korea have appalling jack sockets but they tend to DURDURDUR when playing, not cut out completely. I would still replace them with a Switchcraft USA 1/4" jack (allparts, stewmac etc), but if you have nothing coming out at all, I'll bet that the 'hot' wire from the volume pot has come away from the jack and can be re-soldered by any mate of yours with a soldering iron. I've done it, and I'm no solder-monkey.
Come back with more info and you'll get follow-up.
Lee is pretty much totally right here. In my exp, many cheaper basses from Korea have appalling jack sockets but they tend to DURDURDUR when playing, not cut out completely. I would still replace them with a Switchcraft USA 1/4" jack (allparts, stewmac etc), but if you have nothing coming out at all, I'll bet that the 'hot' wire from the volume pot has come away from the jack and can be re-soldered by any mate of yours with a soldering iron. I've done it, and I'm no solder-monkey.
Come back with more info and you'll get follow-up.