I just migrated all of my boxes to the the new FiOS TV One boxes - on my primary box (DVR) every few minutes the screen will turn black for about a second.. its very random - sometimes it could be 15-20 minutes between, other times it'll do it 2-3 times in a row.
I was thinking it was the 2160p setting, so I lowered it down to 1080p and it still happened. I tried to change afew settings on my TV and reciever and it was still occuring. At one point I had the TV menu system displaying, and I could see the cable image go black but the menu's were still on the screen which leads me to believe its not the TV actually going dark, its the cable box. Not sure what else I can try..
Its a Fios 4100 cable box, Samsung UN65KS8000 TV and Yamaha RX-V779 Receiver
When the boxes went out did you still see one white led on the front of the box? Did it change colors and go back to white? Could you see the channel guide from the box? Are the boxes wired or wireless?