I am rebuilding an Early 2008 Mac Pro. Not knowing the power sequence of the machine I have a couple of conditions that occur.that someone might be able to help diagnose what is missing. I have one E5462 CPU in socket A, socket B is empty 1. On Power Up with all power connectors plugged in the power supply starts up for a second and switches off. The OT1 and Ot2 diag leds are lit. 2. If the power plug next to the speaker, I think this is p1 or p2 is removed the machine powers up PSU fan runs to speed and Ram riser leds test and go out. I would call this working if I felt the CPU heat up or saw video. 3. The board responds to nothing with the CPU removed. Of course I am seeing no video 8800GT card (tested is working) and Northbridge and CPU are cold. Do bad sensors on the heating shut the machine down.? Do bad fans shut the machine down.