Toshiba 55L621U black screen. HaveTV for about 36 months now when I first bought it I noticed that the TV was sometimes turn itself off thought it was a energy saver feature or timer. Pay this no attention just would turn it back on ,tv would work perfect. So last night TV shuts off ,turn back on like many times before but this time ,this happen TV logo comes on screen goes off as normal but power lit flashing, tv screen goes black so i know something else wrong ,called the repair shop and they thinks that is the backlighting a very expensive repair so since I'm a do-it-yourself person, i taking the back panel off plug power back up and noticed all the backlight panel lights are on then i checked the main board for blown capacitors or fuse ,couldn't visually see any what is your advice