TV & Firestick gremlins

I can't figure this out so any insights would be greatly appreciated.

4yr old Samsung TV, 4yr old Sony DVD and 3yr old Amazon firestick. All have worked flawlessly till one day I was switching back and forth between broadcast TV and the firestick. When I went to firestick I had video but no audio.

TV only has 2 HDMI ports, same problem in both. Tried the DVD player in both and had audio and video in both.

Tried every sound setting on firestick and TV to no avail. Did the usual unplugging and updating the firestick. Contacted both Amazon and Samsung support. Amazon has sent me 2 more firesticks and same problem on all, video but no audio. Firesticks work just fine on a friend's tv.

There is no firmware or software updates for my TV.

So why does the TVs HDMI ports work for the DVD player but not the firestick? Is there any kind of work around? I'd hate to have to buy another tv.

Thanks for any help.

 

Sounds like the TV settings are messed up and it's disliking whatever audio format the fire stick is putting out. Is there any way to reset it to factory?

 

Yes I've reset the TV to factory defaults as well as trying every possible combinations of audio settings on the TV and on the firestick. Weird thing is it just stopped working properly without me changing any settings.