If you wish to get some details; check the site linked here. Pull up older posts.
https://elektrotricks.blogspot.com/https://electronicshelponline.blogspot.com/
faults & possible causes of LCD & CRT screen are given with illustrations. You can get an idea about the fault to an extent. Search the site by type in the brand name of your set, in its search bar at the right side column, and press enter. See it in Webview with mobile or by desktop. Mobile View has no search box.