Emu XL-7 & MP-7 User's Group

My worst nightmares have been brought to life! I was playing with my 
MP7 and noticed that my siedlaczek orchestral rom was not being read 
or recognized by the unit. Any preset i tried to use with samples 
from this ROM appeared with '???'. I decided to re-seat the ROM, so i 
turned off the unit, disconnected it, unscrewed it and put the card 
back in, this time in slot 4 (it was in slot 3 originally). I screwed 
the case back together and connected the power and tried to switch it 
on but now i get nothing. I don't get ANY lights or screen, the unit 
is totally non-functioning. I tried taking various ROMs out, moving 
their slots, using different power cables, checking connection of the 
grey cables in the box but i get nothing! I'm pretty sure re-seating 
my siedlaczek ROM did not cause this problem... Perhaps I have blown 
the power supply, busted one of the grey cables or bent a pin, 
however i can see NO physical damage at all, not even a slightly bent 
pin.

Anyone got any ideas how I can test the power supply and/or get my 
unit working again? :(