Which components cause Sony TV dead when hot

Watching TV (Sony 27''), suddenly,I heard a sound " Poof " and TV turned off, the screen came black. I turned it on immediately, it was still dead. On next day, i turned it on

again, it ran smoothly but after 4 hours of running well, it turned dead again. Waiting for another day, I turned it on, it worked well and after 3 hours, it came dead. Waiting 10 minutes, i turned it on again , it ran OK but after 4 minutes, i heard the sound " Poof " and it came dead. Waiting for 5 minutes, turning TV on, it ran OK 1 minute and "poof", it was dead again. I don't know why. I guess that some electronic components are bad when they get hot but I don't know which ones and how to repair

Anyone know what componetns of TV cause the problem and please tell me how to repair it ?

Thanks in advance