Progress, I think. I tried the "soft reset" suggested by loveinthehd, and thereafter I was able, using the Yamaha RX-V685 receiver's remote, to scroll through the various artists, whose names appeared on the front of the receiver. Still no sound and no change on the TV screen, no matter which buttons I poke.
Then I unplugged the receiver and waited about ten seconds before plugging it back in. No change, that is, I was able to scroll through the artists' names but otherwise nothing.
If a factory reset of the receiver requires that I use the TV, keep in mind that so far I can't, i.e., nothing I do with the receiver's remote makes anything change on the screen.
Mark E. Long, I'm not sure how to answer your question, but I like the direction you're pointing, because I suspect, or at least would like to rule out, some sort of error I've made in hooking up the television to the receiver. Is there some way, which presumably I've failed to achieve, that suddenly, magically makes the TV show stuff from the receiver as it's supposed to?
Thanks for the continued interest.