I have a new Lenovo Yoga 2 Pro and a 5 year old Element LCD TV. When connected via HDMI, the laptop recognizes that it is plugged into a LCD TV, but the TV just says "no signal." I know the HDMI port on the laptop is fine, works on other TVs. And other devices work on my TV (Roku, BluRay, etc). But I can no longer get laptops/PC's of any kind to work on my TV (I have tried the laptop of a friend, it also does not work on my TV). So to summarize:
My laptop + My TV: TV "No Signal"
Friend's laptop + My TV: TV "No Signal"
My laptop + Friend's TV: Works fine
Other HDMI devices + My TV: Works fine
So to me that seems fairly definitive that the problem is with the TV somehow, but I don't know why it works with some HDMI devices but not laptops... I don't know enough about the little handshake protocols that TV's and computers do (not even sure if that's really a thing or not). I have tried cycling the windows projection mode (duplicate vs extend). I have tried different HDMI ports on the TV (it has 3). I have tried rebooting the laptop while connected. I have run out of ideas... please help?
You may need to set the video output to extend and change the resolution of the 2nd display to match your TV. Your older Element TV may be 720p and your friends' TV is 1080p so maybe that is why it works on his. Other devices will automatically adjust their output to the TV when connected via HDMI.