Put treats/toys in other locations so that they want to go there instead - a parrot stand if you don't already have one, is a great option. Bonne chance!
It may work and may not but I've seen it work. Find a toy rubber snake and drape/coil it on top of the TV. Even thought captive birds have never seen a snake their instincts recognize it as DANGER... he might avoid it.. or he might attack it.. or.. less likely, could ingnore it totally. Worth aa shot.
I used a word reprimand and asked my bird to step up shortly after, placing them where they are allowed. Consistency is key. Took months before my parrots realized landing on the TV isn't okay, but now they never land on it. They still like to land on the rabbit cage, but that's because a motivator (Timothy hay) is in it and it's rewarding if they do land on it and reach the hay before I get them off. So I continue with the same thing - saying, "Uh uh! Off!", having them step up, and moving them to one of the five places they are welcome to fly and perch to. In the past three months they have significantly reduced the numbers of times they land on my rabbit's cage. I'm hoping it'll reach zero like the TV.
I tried telling them "Off" and rewarding when they flew off, but my IRN was too intelligent and realized that landing on it and then flying off gave him a treat. Created a vicious cycle. So now I use no food reward and only vocal rewards/commands and physical removal. You eventually figure out how your bird responds best.