I'm having an intermittent problem: Trying to turn TV on, the green light comes on with a click sound then immediately goes out with no picture ever appearing. At other times, TV comes on with no problem. When I am having a problem, I unplug the TV for at least 30 minutes, then plug it back in. I wait at least another 30 minutes before trying to turn it on. Sometimes that works, sometimes nothing seems to work and then it will just turn on like nothing was ever wrong. Any ideas as to what part might be faulty?