There are only 2 parts that can cause this effect on screen, and those are:
- Color Wheel
- Digital Video Board
1st you can check the color wheel, open its housing and try to clean it, some times this makes the trick. Just be really careful while manipulating the color wheel since is a very delicate component.
If situation persist after this there is a good chance that Digital board is starting to get bad.
If you can provide us with the TV model # we can try to find the spare parts you need for your TV.
Change is the only constant, we must become the change we want to see.