Chosen Solution
I have an old panasonic plasma tv, model TH-50PX60U, with darker areas on the screnn in a solid pattern that looks like a wave. There’s still a visible picture in these dark areas but it’s very noticeable when there’s a solid color on the screen, such a a football field. Can this be fixed?
No, plasma TVs leave a burn mark on the screen. That’s why they don’t want you to have a solid image on the screen for an extended period of time. You can replace the tubes but it’s not worth it. You can buy a new led TV for less money. Sorry about the bad news. But if you can live with it until it dies completely.