Sound dropped on my 2010 Vizio XVT553SV while watching

My family was watching a Netflix documentary a couple weeks ago using a Fire TV stick on the side HDMI connector when the separate AV receiver clicked as though the source signal had changed. At the time I was running optical out to the receiver. I have tried other methods including headphones straight from the TV audio out, but from that point forward no audio routing through the TV has worked properly. I have confirmed that the AV receiver is working properly.

I have tried Vizio support instructions and multiple online DIY repair posts and reset the audio settings and then the entire TV and also unplugged the TV for a minute. None of these efforts has fixed the problem.

I did notice that my AV receiver driven center channel speaker chirps for a split second with the correct sound each time I change the SRS TruSurround HD, SRS TruVolume settings in the Audio menu or the Digital Audio Out settings in the Advanced Audio menu.

This has been a great TV and I’m hoping it can again be more than just a monitor. I am able to get sound using Bluetooth with the Fire TV stick but I have cut the cord and receive my HDTV over the air using an antennae so not having audio through the TV is a problem.

Thanks for any and all thoughts on what might be wrong here.