When I turn on my 36" RCA TV model 36V55OT, after about 5 minutes the screen goes black. I can still hear the sound but there is no picture. Any ideas on what I can do to fix the problem. I already tried opening it up and using a compressor, I cleaned all the dust near the bulb and around all the components. It turns on and I get picture but only for a while. Then the screen goes black again. I'm thinking it's the bulb, but can't be sure. Any ideas would be greatly appreciated. Thanks!