Chosen Solution
After about a minute display starts blinking. Cannot access self diagnosis feature. I will open it up and have a look at the boards tomorrow.
@mike8888 your panel is a LED backlight panel. If your Display actual appears to turn on and off and thus looks like it is blinking, you may have issues with the backlight array. Your TV should have an LD board and once you have your TV apart post some good pictures of your boards etc.. Clarify for us that you get sound etc. or that you at least checked if you maintain a picture during the blinking, by shining a flashlight beam at an angle against the display. Personally I’d check power board output LD board LED backlight array My number one suspect here are the backlight strips but measure the voltages between main board and LD board etc.
Adding images to an existing question Update (01/29/2020) @jayeff possibly a generic message. I’ve added the SM to my answer for verification Sony-KDL-40W600B-and-more.pdf Hopefully I’ve read it right :-)
