HDMI worked when I got Surface in Nov, but tried to use over holidays and no go. I tried two different cables and three tvs one of which was the one it initially worked on. I can plug BB Playbook in and it works fine but Surface doesn't see tv and tv gets no signal. I have looked around at settings, both locations, and I can find nothing that helps. Is there something I'm missing? I have checked in display settings and adjust commonly used mobility settings. Changing second display to any options does not resolve. I have powered off and on with cable connected and yes, I've checked to make sure nothing was in plug. If I had to make an uneducated guess I would say my HDMI output is bad. I don't want to reset unit, but that is my next step and then return for warranty from there. Any help would be appreciated.