My Sony KV28FX65 has a picture rotation adjustment to allow you to adjust the angle of the picture in the screen if it has been pulled out of true by the Earth's magnetic field. It's been set at -3 since we purchased it 16 months ago. In the last few weeks I've had to re-adjust several times, hence my title question ! I've also noticed occasionally after several hours of viewing a purple hue at the bottom of the picture which dissapears after the set is switched off overnight. The set has been fault free until now. Any comments anyone ?