DDJSX problem...any ideas???

Hi there I have the DDJSX and love the thing but over the last couple of weeks when I've turned it on to use everything lights up as normal but channel two does not work at all, I can't load tracks or do anything else with it, the other channels function normally, I can get the channel to work if I do a firmware update (over write the same firmware) and once that's done it works as expected until I come to use it again a few day later and channel two is dead again :/ it doesn't make any sense! it's out of warranty by a mile so any ideas are appreciated....