How long does a guy have to change channels before a potential burn in can occur? My new plasma has all the protections (pixel shift, etc) but its new and I'm new to plasma's and I'm worried. For example I'm trying to watch ESPNHD and since it's a 4:3 signal shown on a 16:9 TV they have a giant ESPNHD logo plastered on the black bars on the sides of the screen. There are other examples but I think this one would cause the worst burn in since its so huge. Any ideas?