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

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