I am having this same issue. Brand new X1 box we picked up from a comcast store today. We can connect with the coax cable and are able to watch TV, but thats only 720p, our tv can do 1080p with an HDMI cord, but we've gone through 3 different HDMI cords and only get a blank blue screen when we use them. So were getting some signal, but not getting the actual cable coming through. If we were getting no signal the screen would be black with the LG logo flaoting around it.
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