That does not rely on folk having basic skills. BEFORE I SHARE A LINK ABOUT REPAIR: TRY THE FOLLOWING. Power all devices down. Now unplug one end of each HDMI connection. Then unplug all devices from the wall power source for a few minutes.

Here's why. HDMI has a handshake system and you can see this blink as it handshakes. Some HDMI chips seem to do this and to reset those chips you have to do the above, wait a few minutes, hook it back up and test.

Self repair? Try https://www.shopjimmy.com/tv-repair-tips

My view on repair is to always get the service manual and have the background and gear to do the work.