My 42 inch hdtv goes dark?

Question

it will show a good picture at times then sometimes it goes very dark? whats wrong and how much?

Answer 1

i bought a sharp 46 inch LCD tv and it did that, but there was an option to turn it off. but im not sure in your case.

Answer 2

If it is plasma, perhaps the screen protection circuit kicks in when the picture is too bright.
Don't use "Vivid" and lower brightness.