Chosen Solution
My issue is a bit different. Sound, amblight and picture is ok but backlight turns off any time in an hour. İt happens after picture is displayed from any source. If no picture then no problem. Changing tv may be better then change main board. Güncelle (21-03-2022)
Serkan Atan once the screen turns dark and you continue to have audio, shine a flashlight beam at an angle against the screen . See if you can make out shapes etc. If so it is your backlight that may have failed. If not then it is time to remove the back from your TV and take a look at the boards. This can be a power board as well as a main board issue. Since it is listed as a Philips I would consider a bad backlight array. Remove the back cover from your TV and visually check the boards. Take some good pictures and post those with your question, that way we can see what you see. Adding images to an existing question
