Thunderbolt to HDMI external display: no signal

I have a mac air 11" late 2011 and can't mirror display with a thunderbolt to hdmi cable. I tried on my sony bravia KDL46EX705. The display is detected, it shows SONY TV, but no image on the tv I've tried resolutions, Hz, and a couple of other stuff at the tv that did no work out. all softs and firms are uptaded. Tried also on a Phillips 42" and the same. I've bought both mac and cable at the 5th av apple store.