Hello, it is one blink every 4 seconds.
Here is the fail code information --
It looks like the A board would be more likely than the panel, unless it was damaged somehow. Usually the LCD panel should glow, then it produces a picture once it starts to glow. The A board sends that picture signal to the Tcon board located at the top center of the LCD panel, and that requires 12 Volts DC to energize that board.
It's 50/50. The A board is costly, but the panel is about the cost of a whole new TV set, and while the TV is young enough to have an A board failure, Panels can fail too.
Here is a picture of your main board. Follow the instructions to get the TNPH number so you can use Google to find that part --