Over the winter I had this exact problem and after several reboots of the STB it seemed to resolve itself. Two days ago (almost 6 months later) it re-appeared,
The specific channel doesn't matter - though it was always on HD channels as far as I know - since thats what I usually tune in to. Suddenly, the signal seems to shut off completely and I get a black screen. (I have seen the TWITTER notice on the upper right of the screen while it's black) - and if I simply change the channel with the remote - up or down, the picture returns. This continues to happen - at no specific interval and with no regularity until I reboot the STB. Earlier today I called FIOS and the tech rebooted or reset everything remotely. When I reattached things I had the nicest, clearest picture. I realized that I didn't even notice I wasn't seeing a true HD picture for some time. Then as I continued watching the same channel (CNN - don't judge me :}) it began looking more and more red tinted and not HD.. So I went online and reset it through the website and again when it came back on - perfect picture.
I walked the wiring outside my house - it is a convoluted trip from the front to the far back side, but all wires appear un-corroded and not in touch with anything. Is is possible I just have to keep re-initializing because of a STB issue?
Any suggestions? I'm reluctant to lose the recordings on the DVR = motorola.