Thanks for all the feedback, it's much appreciated. I had this same problem with this same machine a year ago. Than for no apparent reason it started worked fine again, until now so I took the top off and played a c-d so that when it started acting up again, I could see if the laser was going on and off in conjunction with the sound going on and off. But I could not see the laser as it was playing, even with a small mirror. I also couldn't get it to act up again, even after several hours of playing. So I put it back in the system and so far it has been working fine. I did clean the laser lens with a cue tip and a liquid lens cleaner before doing so, and It seems to read the c-d's a lot quicker now.
I was also having intermittent trouble with the tray not opening and closing properly, but so far that seems to be working fine as well. I don't know what to make of it.
One afterthought, when the sound would go off, and than on again, it would pick up from where it left off, almost as though you hit the pause button on the remote. I wonder if the problem might lie in that area.