Magnavox CDB-473 squeals when powered on

Years ago I bought a Magnavox CDB-473, but I stopped using it when it seemed like the laser was going bad, and replaced it with a somewhat inferior (but cheaper) Philips 920. Recently I got it out of the basement and on a whim fired it up. It seemed to play flawlessly -- no tracking errors and the sound was fine. The only problem was a brief squealing noise when powered on. I removed the cover and noticed that when turned on with a disc in it, the disc would move a little and stop, there would be a squeal, then the disk would start spinning again then stop after the disc info was read. It's not the disc rubbing or being inadequately clamped because there's a power-on squeal with or without a disc. As I am a newby to all of this, I would appreciate some ideas as to what to check out before I disassemble it and then realize that I have no idea what I'm doing.
If the unit has been sitting around for a long time, it may be a mechanical issue. Some rust or dirt could have accumulated somewhere. I would let it play for a while and see if it goes away.