I've got a TCL TV with in-built audio. I can hear audio when I click the remote and navigate, but none of the audio works for videos, whether Amazon Prime, Netflix, Hulu, and the rest. I also tried a USB stick. No dice.
I am not connecting to external speakers, and since I can hear something, it's not a hardware issue.
I have tried different audio settings, regular as well as 5.1. I have also tried hearing impaired, director talk tracks, and different languages. All with no success.