Mine also does this intermittently. Most of the time I also have a white flicker when it is working. I have posted today about the problem, I also replace the HDMI cables (wow they are expensive) hoping to correct the issue.
Just bought both a Samsung 55" LED 6300 series, and a Samsung C5500 Blue Ray home theater and they will not connect to each other using HMDI cable. They connect fine with component connections, but not at 1080p. The tv finds the theater and recongises it, can turn it on, but then tells me it is not connected and to check the connections/power. I even went an bought new HDMI cable and still nothing. I have tried reseting by holding down the stop button for five seconds as suggested in the manaul, and nothing. What am I doing wrong? Help