What's Wrong?

It sounds like an HDMI compatibility issue here.  How old is the TV?

2011 Panasonic - never had any HDMI issues before and Fire Stick worked with no problem when I had it connected to a Blackbird HDMI switch for a brief period recently. I have moved a newer Samsung into place and will be hooking that up tomorrow. The Samsung is the reason I got the Blackbird to begin with, because it does not have an optical output, which causes all kind of issues I won't go into here. But my main goal is to get sound without having to use an AVR, whatever that takes. The Samsung is very limited on connection options.

Well, mahler123, you may have been on to something as far as the HDMI issue was concerned (or not).....after connecting the Fire Stick directly to the Blackbird switch and then connecting the Blackbird's HDMI output to the Samsung TV, I now have audio through the TV speakers. The switch has a second HDMI input port, and I am trying to figure out the correct procedure to connect the AVR's output in order to have video/audio feed from the AVR. My first thought is to connect the AVR's HDMI output to a second HDMI input on the TV, then toggle between those inputs as needed. Thanks to those who offered tips in this maze of issues.

The AVR should have a hdmi and audio pass through option in settings, i.e., the AVR can be in standby and it will still send the last input it was set to (your firestick plugged into the avr input to tv).

Not sure about entry level junk avrs.....

The AVR is an older Onkyo TX-NR1007, which is a fairly feature-laden unit that is a good performer. I will check the manual for the pass-through option (which if it is available, will simplify things a lot).