How can you tell if a dlp picture tube is burned out

Ok I had a problem with a banding on a 57 inch sony DLP, It was burn in from thr ticked that runs on CNBC when I was trading everyday. It took the 8 months to return the set after 6 tries at trying to get me to accept it, The ended up changing all 3 guns, the power board, and the front glass which they cracked one time and scratched the second,I was on a first name basis with the VP from the chain store. She was a very nice lady and we became friends. Meanwile the final time the forgot to scre the wheels back on, so they called 2 more techs to tilt it while one screwed in the wheels. Two days later the same thing happened, the VP told me they had spent over $2000.00 dollars on a 1,500.00, dollar tv. She sent me a gift card for a new set and that was that, Both Dlp's and Plasmas will, Burn an image onto the screen within 15 minutes. I only suggest LCD tv's. Especially if you pause things and forget or they are on, video games, especially, you will surelly screw it up. There may have been a ticker scrolling or a paused show on your set and it may be burned into the screen or gun itself. Even pictures from your camera will do it, most manufacturers leave themselves an out even on the sets tha say they are burn in proof. Do,not buy Plasma or DLP tv's, they all have burn in problems even if the salesman tells you different, A simple search will bring up hundreds of articles from folks who were not made aware of this.