My fire tv failed about a month after the window of being able to return it for a replacement. I tried using a different tv, different power cord, and everything outlined above. No matter what I did all I got was “no signal” on my tv. Eventually, I decided to take it apart and I heated it up with a hair dryer for 5 - 10 minutes or so till it was good and hot. Then let it cool down. Plugged it in, and it works fine again. Hope this helps someone else as a last resort.