Says no signal when switched to hdmi when there is... I just hooked an hmdi cable to me tv from

Question

I just hooked an hmdi cable to me tv from my cable box. When I swith to the hdmi input it says no signal when I can clearly see the picture coming from my cable box and then after a few seconds it just turns to black. Anyone have any idea what is happening?I hooked up my olevia 232t12 to my cable box and switched the tv to the hdmi source and the tv reads no signal. I bought a new hdmi cable and switched out my cable box as well and still no signal. I have tried to get a firmware update for the tv at the olevia site, but there is no update available. I'm begining to think its the tv.