Just saw this.

Want an experienced wild ass guess? It sounds like you may have 2 Saturns with varying degrees of dead motor. There is a "disc swap method" that allows a user to play CDR copies of games, but it is VERY hard on the CD motor. If you did not own either of these new, that's a possibility. Another, somewhat related, woul be the "disc lid open" switch could be faulty, and possibly bypassed. It should tell you if it thinks the lid is open though (even if it isn't). Discs won't spin, if it thinks the lid is open.

These are wild ass guesses based on not having seen your Saturns. I fear both of your Saturns suffer the same malady, which means making one working could be difficult.

Good Luck!