i'm interested in this as well, as half my working CD drives (IDE, SATA, doesn't matter) will no longer eject or have to be manually ejected a few times to start working.

The only thing I found online about fixing cd-rom drives is "change the belt" and "grease the gears". Did that on 4 drives, different years and manufacturers, and they still won't eject. It feels like they stick someware.

Here's an article on how to do floppy drive alignment-- https://polprog.net/blog/fdalign/

The CD Rom drawers that don't open could be a broken eject button, dirty mechanism, a broken motor, or a broken belt

https://www.computerhope.com/issues/ch000214.htm

If, after following the above recommendations you cannot open the CD-ROM drive using the front button, it's likely defective and should be replaced. It is not worth trying to repair a defective CD-ROM drive.

having disassembled both my cd-roms, theissue is that the driving spindle does not cleanly disconnect from the dome on the inside of the lid. with the lid off, they cycle perfectly. have not found a fix yet.

I've found that a way to refresh the drive's belt is to gently hold it against a rolled up Scotchbrite pad with my thumb and use my other hand to pull it through several times. This takes off the hardened layer that makes the belt slip.

I'm curious about repairing older CD-ROMs as well. I have a Toshiba 6x CD-ROM that won't open properly. It sounds like the gears may be slipping.

It's an all-plastic affair (no belt) on the inside which has made it a bit tricky to disassemble. Haven't gone further than what is pictured, but I'd be curious to know if anyone has had success repairing this type of drive.

might try that, ive got a few that require a love tap on the case to open

if you can leave it apart like that and give it power, it could be possible to see if its a worn out gear or not. I wouldn't have any clue where you could get a new gear. But you could try greasing the gears with some plastic grease. On that note lubing the entire mecanisim and the gears on the tray etc might help alivate friction so it opens closes. might be the gear on the capstan motor that drives the tray. That could be replacible.

I do have a Cd drive with no belt. A NEC if I remember correctly.
It had issue to open as well. I fixed it by cleaning and greasing all the movable parts.

Clean and grease is never a bad thing for old drive.

I had one CD with a cracked small nylon gear; it was pressed onto the axle and with time it eventually failed, splitting open between two cogs.
Got a replacement from a scrapped drive with same gear size.
(An attempt at gluing the original didn't help, as the stress made it crack open again when trying to reseat it, and if the gear cogs were not properly spaced, it would snag on the meeting gear).