Hey there. need a lil advise. I have a sony flat screen tube tv.. it was manufatured in sept. 2002

Question

I have a sony flat screen tube tv.. it was manufatured in sept. 2002 so its kinda old, well when u 1st turn it on its the clearest screen you could ask for then less than 5 mins and the screen fades out slowly to red...the sound works fine..what Is the problem and how much will this run to fix... thanks