I can add to this, it is the drive cycling through the disc insert then disc eject process. Because no disc is present, there is a gear that doesn't engage (linear gear which is tied to the laser carriage). It's almost like the drive thinks a disc is being inserted randomly, and when it doesn't physically detect a disc, it then switches to the eject process. I'm baffled. I know this is an old post, but I haven't found anyone else with this issue after a lot of searching so hopefully someone knows the cause/remedy. Update (09/06/23): I have narrowed down where the physical issue lies, I assume it is a sensor in the middle of the slot. Video linked below. Again, everything works fine when a disc is present, so the issue must be a very touchy or loose sensor/actuator just inside the center of the slot load mechanism, about 0.25" from the front of the drive. If anyone has a junk DG-6M5S-01B drive that they could sacrifice to tear it apart and find the culprit, that would be awesome....