Well, I can answer my own question
It appears that the loading tray got "stuck" in the loaded position without
a disc being loaded. I did have one empty slot, and possibly "loaded" that
To fix the problem, with the unit off, I manipulated the mechanisms by hand.
This takes two adjustments.
1. There is a vertical escapement that keeps the tray from moving to the
unloaded position. Just rotate the wheel that moves this escapement. It will only
rotate in one direction when the tray is in the loaded position. Once the escapement
is moved to its upper position....
2. Rotate the wheel on the top of the drive mechanism so that the tray
moves outward from the center. It is to the left if you are looking down on
the device from the front.
Once the tray was in the unloaded position, I turned the machine on
and it came back to life. Lucky me