Well it is pretty catastrophic to me ;-)
I have an ASUS CRW-4012a that has been working great for years now, and has recently started to have "issues" seeing a disk in the drive and it started making noise, (the kind of sound that makes you think a plastic disk is slipping and there is friction noise from it).
Since it is no longer covered by the manufacturer warranty, I decided to take it apart and see what was going on.
At first I couldn't figure out what could be wrong as all the motors seem to operate normally, and the gears are intact. There was a bit of dust, but I cleaned that out and re-lubed the stepper gear as well as the rails the head travels on. I then started to focus on the clamping mechanism. Typically what I have seen in the past is on the spindle there is a magnet of some type attached (screwed or glued), in this units case, there was what I identified as a magnet, but parts of it were shiny (hardly any) and other parts were rather black, like as if it had some funky gunk on it. I went to wipe it off and discovered the funky stuff was the magnet.
It would appear that this (and I guess many now) magnet is made by taking a ferrite magnetic powder and encasing it with a layer what looks like chrome. The problem appears to be that the outer shell wore away somehow or was damaged at some point (more likely they knew it would die after a couple years and people would just buy entire new drives) and then we only had loose magnetic particles trying to pull down the upper platter of the clamp and spin it. That explains the noise and it's failure to spin up properly (especially at 40x).
After cleaning some of the material that had been thrown onto the few metallic parts in the unit I was able to verify the drive is still functional, but I need to replace the clamping magnet.
Does anyone have any idea where I might find a non powdered replacement or what I should look for?