Rotation can affect image purity. You don't even have to turn the set upside down. If you have a set that already has some color purity issues due to bad magnet

Rotation can affect image purity. You don't even have to turn the set upside down. If you have a set that already has some color purity issues due to bad magnetism of the mask, you can affect that (and sometimes even find a position that eliminates it) simply by rotating the TV around on the surface it rests on.