No saying that this is what is happening to you but I got almost the same problem.The image goes blank for some time and then comes back.
What I found was that the screen was overhiting due all the crap that is behind of it.
I put 2 low profile 40mm fans and I haven't seen the problem anymore.
Sometimes we think is a powe related and we overview the simple things that can also happend.
Hope you fix the problem.