I am out of the game for now. I decided to take a break for a while. So I disconnected the trouble cube and plugged the PSU into the cube that I got working yesterday, and when I hit the on switch, the PSU just sat there like a big shiny paper weight.  Yep, blew a 1000 watt Zalman power supply.  Thankfully I can return it as it is only a week old. 

Yesterday this cube did the same thing with a 700 watt PSU, so now I am wondering if I got hold of a faulty cube (or two). I know it is unlikely, but not entirely out of the realm of possibility.