Thanks so much for your replies.
Schipo - the motor seems still to be OK in that the drive plate WILL spin a bit when the turntable rotates to each of the 5 positions for a CD, but when it then lifts a CD to play it, it does not spin the actual CD. I am wondering if there is some beam "recognition" of the CD that must take place before the CD will spin and be read. Any thoughts there?
Elizabeth - I will again remove the cover and try as you suggest. If this maneuver fixes the problem and all CDs start every time after that - I owe you a big hug. However, further intermittency would lead to deeper frustration and more hair pulling. Thanks.
Buconero117 - you may very well have the most effective diagnosis, and I am prepared to do so. Thanks for the recommendation for the reconditioned Sony 595. If not able to fix this soon, will do exactly as you suggest. As it turned out over the long run, the 5 disc changer feature is of almost zero importance because I am a very selective/analytical listener in the music theory sense and a single CD player would be more effective.