HP-R5072 50 in. HDTV Plasma Television\r\nSamsung

Most likely it sounds like a Logic Board problem. The Logic Board is what controls images on the screen. It's a somewhat expensive part to replace. Maybe in the $200 range. Being that the part isn't cheap, best to have a TV tech come to your house to take a look at the TV to confirm the diagnoses before buying the replacement part.