I had 3 of these connected to a single Raspberry Pi for well over 6 months. I had a single ATX supply for the 12V to these, and the 5V to the Raspberry Pi. It ran un-touched for those 6 months at a steady 96+ Ghash. Supply good power, and a little ventilation and they will run fine, in my experience.
Yeah this is what I thought, they have good reputation if not a little fragile. My supply was 12V too. It must have been damaged in the shipping. I have picked it up a few times etc but in now way to damage it.
Well I guess if it's dead I got nothing to lose but open it up and try and fix it!
Thanks everyone for your comments. Much appreciated.
Tom