It does not appear to be possible to post pictures. If you know how, I'll post.
Thanks for the thought about contacting Klipsch -- I e-mailed them & Onkyo as well. For lack of a picture, that we try again to describe what I see, since it is really very, very simple. On the back of most any audio equipment I've seen there are red and black push clips to connect speakers, one pair for each channel. On the back of the Onkyo, I have a pair for front left in a pair for front right.
The normal wiring on my old receiver was to run the front speaker wires to the back of the Klipsch, where it has the exact same type of connectors labeled "from amplifier." The front speakers are in the system via a second set of the same connectors, i.e., a red and black pair for the left front, and another for the right. These are clearly marked "to speakers."
There are also 2 pairs of RCA jacks, one red one white per pair, similarly marked as being left and right input.
And that's it. The rest of the back is an off switch, a fuse (which is just fine, I checked), a rotating dial for volume, and a similar dial to set the crossover frequency, which I know means what part of the signal stays with with a subwoofer and what is sent on to the fronts.
Yes, I tried telling the Onkyo there is no subwoofer, which does indeed mean the entire signal to the fronts should have been sent out to the sub woofer, divided then by the Klipsch, and the appropriate signal sent on to the fronts.
The Klipsch is a powered subwoofer to answer one of the questions. An Onkyo documentation does reveal that the subwoofer out is a preamp signal. If I could get that to the Klipsch somehow I'm sure the Klipsch could amplify adequately from there.
I am sure this could be a defect issue. It just seems so unlikely the unit worked fine the night before, but went out the very day I took the old receiver off-line. Maybe I'll re-attach the old receiver to see if the Klipsch works, which would prove defect/breakage is not the issue. But where would that leave me? I would know everything works, just not together, which is sort of where I am now (even if partly by assumption).
Thanks again to everyone who posted! If Onkyo or Klipsch can solve this, I'll post the answer.