All are considered "no user serviceable parts inside" areas. If you are a TV or electronics tech, go get the service manual first. Only those that want to be upset go without that. Some even flame others for not being able to diagnose TVs without that or having the set on the bench. So you'll need the basic repair gear, the service manual and then you are ready.

There are many youtubes about blank screen LCD TVs and if you watch a dozen you find about 6 issues. Watch a few hundred and you'll likely find about a hundred causes. Which is it this time?