You should determine if the problem is hardware related or software, does the screen give any sligh light? Like when you turn the phone on and it is black just a little bit lighter you know? Did that happen suddenly? You could (shouldn't of you have no knowledge on that) open the TV and check connections and the capacitors on the boards, IF you have knowledge on that of course... If the screen really gives no sign, it probably is a hardware rated problem. If it gives a sign like "turning on" but only showing black, could be a system problem, anyway that should be fixed by a technician, because there is not much to do on a TV, for someone that doesn't understand about tvs.