I have a samsung drive as pictured here:
http://www.llamma.com/xbox/Repairs/Images/...msung%20027.jpg

The problem is that it will not eject. I have disassembled it, and found that when I remove the metal top (see the pic above, the top left piece), it works fine, opens no problem. Whenever I put the metal top back on, it seems as though the magnet is holding the drive in or something. Any ideas?

It seems the plastic disc on the top metal cover is not releasing the tray, causing it to lock. Any ideas?

It works fine when i hit the top if the drive while pressing eject - but that is not a feasable solution.....

is caused by the magnet of the dvd drive, I've the same problem

got the same problem. i thought maybe it was something that was rubbing against the drive and causing the drive not to open

You'll probably find that its the drive tray belt that's slipping, due to the belt being stretched.
Replace the belt and it should work ok.
Regards,
DarkMatter

You can also use a bit of electrical tape on the top spindle. It weakens the bond & makes it easier for the dvd drive to release the tray.