18 Dec
2006
18 Dec
'06
12:17 p.m.
About 1/4 into the tape something started vibrating,
quickly
escalating and before I could do anything, the tape stopped. Result:
rubber goo on the plastic roller that drives the DC-600 cartridge
drive belt, some on the tape itself, and the tape shows deformation
(wavy) on the top half. I had to toss it.
This is the classic failure mode for the rollers. Pressure/Temperature
causing breakdown of the rubber.
Any idea what could have caused this and how to
prevent it?
There is no way to prevent it. The rubber had already decomposed, and
the elevated temperature caused what was left of the bonds to change
state.
The other option is to remove the melted rubber roller
and
steal the one from the Archive drive.
They aren't interchangeable. The only option you have is to find a newer
drive with a roller that hasn't decomposed (yet..). I know of no
commercial source for just the rollers for either Archive or Wangtek.
Wangtek changed their roller design on later drives. Archive didn't, so
you may be able to find 150meg drives that are new enough to survive.
The most common source are Sun external 150meg shoeboxes, which have
been readily available in the past.
18 Dec
18 Dec
12:53 p.m.
On 18 Dec 2006 at 9:17, Al Kossow wrote:
Wangtek changed their roller design on later drives.
Archive didn't, so
you may be able to find 150meg drives that are new enough to survive.
The most common source are Sun external 150meg shoeboxes, which have
been readily available in the past.
This "goes to goo" seems to be manufacturer-related. I've got a
Wangtek drive with a gooey roller, but a Tandberg of the same age is
just fine, as is a Caliper.
If I check McMaster-Carr's online catalog, I see a bewildering number
of choices under "Rubber tubing". Does anyone have an idea about
what works best?
http://tinyurl.com/y6pv4y
Then, there's heat-shrink neoprene tube; might work where a very thin
coating is needed.
Cheers,
Chuck
1:15 p.m.
On 12/18/06, Al Kossow <aek at bitsavers.org> wrote:
This is the classic failure mode for the rollers.
Pressure/Temperature
causing breakdown of the rubber.
There is no way to prevent it. The rubber had already
decomposed, and
the elevated temperature caused what was left of the bonds to change
state.
Hmmm, my next idea - just for obtaining the data, not the long-term
preservation of the drive - is to write a quick and dirty script or C
program to read the data off the drive slooooowly. After all, it took
a considerable number of minutes of the drive going at full speed to
cause the rubber to fail.
If I read one block, then pause for a bunch of seconds, I think I
could do this in a careful enough matter. The problem is I only have
one shot at this, so I should give a generous cool-off period.
Joe.
4:37 p.m.
On 18 Dec 2006 at 13:15, Joachim Thiemann wrote:
Hmmm, my next idea - just for obtaining the data, not
the long-term
preservation of the drive - is to write a quick and dirty script or C
program to read the data off the drive slooooowly. After all, it took
a considerable number of minutes of the drive going at full speed to
cause the rubber to fail.
Maybe, but recall that you're dealing with a streaming drive, so it's
read a block, stop, back up and get a running start, and read the
next one. That "backing up" is what would concern me--any "goo" that
came off the roller would lodge itself between the tape layers and
make a perfect setup for stripping oxide from the substrate.
Cheers,
Chuck
19 Dec
19 Dec
5:40 a.m.
Dunno why
you get so worried in that, in Brazil these rollers are
easy
to find, in USA you can find them at JAMECO or NTE easily...
Can you supply a URL?
18 Dec
18 Dec
9 p.m.
Joachim Thiemann wrote:
On 12/18/06, Al Kossow <aek at bitsavers.org>
wrote:
I'd say get the newest drive you can... inspect the roller beforehand...
then run a scrappable tape through it a couple of times... re-inspect the
roller... if ok... then recover your tapes.
I doubt the method you propose would work.... heat is a factor... but
pressure is likely a factor too... probably still make goo... just more
slowly.
This is all my opinion of course.... I'm not saying I'm right... just
how I'd
go about it.
-- Curt
This is the classic failure mode for the rollers.
Pressure/Temperature
causing breakdown of the rubber.
There is no way to prevent it. The rubber had
already decomposed, and
the elevated temperature caused what was left of the bonds to change
state.
Hmmm, my next idea - just for obtaining the data, not the long-term
preservation of the drive - is to write a quick and dirty script or C
program to read the data off the drive slooooowly. After all, it took
a considerable number of minutes of the drive going at full speed to
cause the rubber to fail.
If I read one block, then pause for a bunch of seconds, I think I
could do this in a careful enough matter. The problem is I only have
one shot at this, so I should give a generous cool-off period.
Joe.
9:29 p.m.
In article <458747D6.1040100 at hawkmountain.net>,
"Curtis H. Wilbar Jr." <rescue at hawkmountain.net> writes:
I doubt the method you propose would work.... heat is
a factor... but
pressure is likely a factor too... probably still make goo... just more
slowly.
Just spinning it is a factor. I think these materials essentially
become metastable over time and that depending on how much bitrot has
settled into the piece it may not take much for it to become goo. I
mean, just leaving the drive sitting there long enough eventually
causes them to become goo, so its not *just* a function of applying
heat or pressure to the object. Certainly the more stress you put on
it, the higher the likelihood of disintegration.
--
"The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download
<http://www.xmission.com/~legalize/book/download/index.html>
Legalize Adulthood! <http://blogs.xmission.com/legalize/>
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