Hello There....by your description of the magnet, it sounds like a
Neodymium or "rare earth" magnet.
These are usually coated in "chrome" and if you chip the coating away the
underlying magnet has a "powdered" look
to it. These have now become VERY common and you should be able to find a
suitable replacement. Do a search for
"rare earth magnet" on the net and I'm sure you'll find some place in your
city that carries them. I live in Canada
and a place called "Lee Valley Tools" has them in various sizes and shapes
for a dollar or two each. The smallest they
carry is a mere 1/4" in Diameter by 1/8" thick !

Good luck......Dean.



wrote in message
oups.com...
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?