Dear Guru's Today its a disaster as my MAc Pro 2009 EFI hacked 2010 was not booting up. I've got black screen with no chime. I've tested the display on a PC and its working. Replaced the power supply with a spare unit and symptom remain. I did remove some RAM just left 2 pcs and symptom remain. There is no Error LED lid and i've no clue where the problem lies. I suspect it might be either the Logic board or Back panel. Any guru here can help me to narrow down more to determine which part might be failing as both Board cost me a fortune to have both replace. Also one very important question since i've mod the EFI to 2010 Mac Pro 5.1 can i replace the Processor Board to the Mac Pro 2010 to have it work like a 2010 MAc Pro as i cant find any answer from Googling.