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CD-R/W drive spindle clamp magnet catastrophic failure.

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?
 
D

Dave D

Jan 1, 1970
0
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?

You probably don't want to hear this, but my advice- bin the drive and buy a
new one. They're not exactly one of the more expensive PC parts, and if it's
years old there'll likely be other parts near the end of their life. You can
get a dual layer DVD writer now for far less than a CDRW of that vintage
would have cost. You might find a similar magnet in a scrap drive, but is it
really worth the bother?

Dave
 
J

James Sweet

Jan 1, 1970
0
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?

My advice is to look for a dead drive and salvage the clamp from that, it's
not gonna be worth buying a new part.
 
D

Dean B.

Jan 1, 1970
0
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.
 
M

Mike Berger

Jan 1, 1970
0
The magnets are made that way because they can't get the same
strength out a rigid material in that size for the same price.
You probably won't find a harder replacement that will fit.

I doubt they made them fail intentionally. Those magnets
don't fall apart of their own accord, but hard contact will
break them.
 
Dave said:
You probably don't want to hear this, but my advice- bin the drive and buy a
new one. They're not exactly one of the more expensive PC parts, and if it's
years old there'll likely be other parts near the end of their life. You can
get a dual layer DVD writer now for far less than a CDRW of that vintage
would have cost. You might find a similar magnet in a scrap drive, but is it
really worth the bother?

I'd rather not replace it with a DVD writer as I already have one. I
like to have a decent 40x CD-ROM for games and burning CD media saves
wear and tear on the DVD drive.
I also enjoy troubleshooting/fixing things, so I thought it was worth
asking.
 
D

Dave D

Jan 1, 1970
0
I'd rather not replace it with a DVD writer as I already have one. I
like to have a decent 40x CD-ROM for games and burning CD media saves
wear and tear on the DVD drive.
I also enjoy troubleshooting/fixing things,

Me too! However, I don't spend more than about ten minutes on CD Roms these
days though, I quickly discovered most failures are not worth the time and
effort.

so I thought it was worth
asking.

Always worth asking. Good luck with the repair.

Dave
 
The strange thing is this is almost my youngest drive in the house. All
my significantly older/slower ones still truck along, and my other 40x
units (different manufacturer) seem to be fine. I have not mistreated
it so I can only assume the drive/loading mechanism must have somehow
been causing damage to it.

As for intentional design flaws, that is just my cynical side saying
the worst about corporate thinking. I know a lot of gamers and they
would just toss a drive (or other component) that quit working and buy
another, even if it was easily repairable. Back when that stolen
electrolyte formula was in heavy use I managed to get quite a few
motherboards to fix due to this mindset. Speaking of intentionally bad
design, those gateway lunch boxes that have only a sleeve fan in the
power supply are quite evil. I just finished repairing 6 for a
preschool, new caps all around and real bearing fans put in the power
supplies. IMO there is no way that bad of a design was accidental.
 
Thanks you (all of you) for your replys. When I was starting to look I
ran across a TDK PDF file talking about the product the magnetics
division made and things they are used for. From what I could tell they
have 3 types they make for drive clamping in the ferrite dry
anisotropic type (formula is SrO6Fe2O3) parts FB5D, FB3N and FB3G.
Shape according to them was called DH (I'm guessing for doughnut hole).

I'm going to cannibalize my 1 dead drive (a DVD/CD-R combo) that
overheated and see what I can do, and then check on what I can find
based on what you suggested.
 
S

spudnuty

Jan 1, 1970
0
Don't know about the clamping magnets but simular magnets in pager
motors and other motors indoor flyers use have had that same issue.
They are formed rare earths with chrome overcoating and they all fail
in the same manner. The crome just flakes off and jams the motors. It
must be a manufacturing problem. If you posted pics and dimenslions we
all have lots of junked CD-ROM drives that we could send you a simular
part.
Richard
 
J

James Sweet

Jan 1, 1970
0
I'd rather not replace it with a DVD writer as I already have one. I
like to have a decent 40x CD-ROM for games and burning CD media saves
wear and tear on the DVD drive.
I also enjoy troubleshooting/fixing things, so I thought it was worth
asking.

Aren't most DVD writers faster than that? My CD-RW drive is 52X and was
under 50 bucks several years ago. By all means, try to fix what you have,
but I really wouldn't worry about wear and tear on a DVD writer, they're
well under 100 bucks now and will likely be obsolete long before it wears
out.
 
T

Tom MacIntyre

Jan 1, 1970
0
Aren't most DVD writers faster than that?

Maybe now, but a year-and-a-half ago, one of the selling points of the
Lite-On drive I bought was that, unlike other brands, similar (to
CD-RW) CD performance was possible.

Tom
 
F

Franc Zabkar

Jan 1, 1970
0
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?

I'd be wary of replacing just the magnet. Balancing could be a big
issue.

-- Franc Zabkar

Please remove one 'i' from my address when replying by email.
 
S

spudnuty

Jan 1, 1970
0
I'm thinking "replace the whole thing".
I also just repaired a Daewoo DVD player that had a balance problem in
the clamping assembly. The assembly was not completely snapped
together. It had either come unsnapped or was never snapped completely
in assembly. It was so bad that you could feel the vibration when the
unit spun up. The client said it just wouldn't read some DVDs
Richard
 
M

Mike Berger

Jan 1, 1970
0
The doughnut shaped ones are not hard to balance.
 
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