Crack it open, and check the capacitors, especially the power supply capacitors. Replace them with better capacitors than you took out. 95% of the time, the failure is a specific power supply capacitor. The data sheets for components have a graph telling you exactly how long you should expect the components to last under certain conditions, so they design them to last maybe a week longer than the warranty. The main power supply capacitor is easiest to design to be the weak link. Paying someone else to repair it is usually more expensive than buying a new TV. The reason is, that these guys are usually also the same guys selling the TVs. This is all just to get more money from you. My electronics degree has more than paid for itself just by repairing electronics around the home that were designed to fail to force you to buy new.