i'm borrowing a friends Yamaha RXV630, i think that's the model number. anyway, i'm sure i haven't broken it (at least i hope not) but i can't get it to work anymore. one day it just refused to play. the receiver (sorry not just an amp) is on, ready for the signal, and when the dvd actually starts the yamaha immediately shuts itself down. like the signal is causing this. has anyone any idea why?