Apple TVs are pretty cheap here in the USA, starting at $139. I think the cost of repair would be more than the cost of a new one. AFAIK
they do not actually repair them here in the USA, but will swap one out if it is still under warranty.
Which model/generation do you have?
Here is a link to some pricing, in the USA> https://support.apple.com/apple-tv/repair/service/