I'm having similar issues with my BF. I bought the update kit for the power board like Erak recommended and when I went to install it, it appeared to have already been replaced. So I checked the voltage to the Display and it registered at 5.0v
I've unplugged/replugged all the ribbon cables and still get no DMD. The game works fine and is completely playable.
Any suggestions from here? I will check all the grounding this evening...