Actually I've never had a cat sleep on a TV, my scanner is the only thing t hat my cat has slept on that I wouldn't think of as a good place to sleep f or any lenght of time. Even as a kid living with my parent who had upto 4 c ats at a time, they never slept on the TV always chose someone's lap. Where they did spend a lot of time sleeping was in the kitchen on top of th e wall cabinets as it was far warmer, darker and quiter there.
But I know cats do like to sit on warm things like TVs given the chance.