Blinks Blue Light 3 Times Then 4 Continuous Blinks

Hello, I recently had similiar problem with the same model tv. It's a simple solution, but some that requires you open up your tv. You have to remove the back in order to view the power supply board. On your set it is the board above center. It has some large D size battery looking capacitors. There are two on the upper right of that board. Check and see if they are bulging at the top and check the rest while you're at it. One of mine was bulging and I replaced both. Then go to the left side and you will see two boards that look like each other. One on top and one on the bottom. They are the buffer boards. Check the littel square IC's on there and check if any are burnt. One of mine was burnt on the lower buffer board. I removed the bad board and turned the tv on. The upper part of the screen did turn on, which confirmed the lower board was bad. The capacitors, when they blew allowed a surge of current to go through and cause damage to the buffer board. The caps you can buy at digikey part number EKMH101VSN332MR50T and the buffer board I found on ebay for 54 USD. SDR-D ND60200-0048  if you need the upper then just change the last number to a 47. Hope this helps.