I'm having a problem where if I turn on my TV, I only have about a 50-50 chance of receiving a signal from my Comcast STB. I get "No Signal" or it comes in fine. If I pull the power from the box and power it back up I get a signal, except it takes 20 minutes or so for the guide to update. The hookup is HDMI to HDMI. Anyone else have this problem?