Formatting non-DEC disks using zrqch0...
Curtis H. Wilbar Jr.
rescue at hawkmountain.net
Wed Nov 15 21:55:48 CST 2006
Josh Dersch wrote:
>> Josh Dersch wrote:
>>> The RD53 drive in my 11/73 has finally gone to silicon heaven, after
>>> a brief resurrection. Given the reputation these drives seem to
>>> have, I'm not too surprised. So a few nights ago I dug through my
>>> stacks of ancient hard drives and found three possible candidates
>>> for replacement:
>> RD53... Micropolis 1325 I believe. I ran one of these (I believe it
>> was an RD53
>> actually... not just a generic 1325) in a PC years ago.
>> It one day started not wanting to initialize... startup... think
>> think, chunk chunk,
>> spin down....
>> With nothing to lose, I began to experiment...
>> What I found was that it couldn't apparently locate track 0. If the
>> HDA os opened,
>> it has two rubber? bumpers for the extreme ends of head motion. One
>> for track 0
>> and one for last track ?
>> They look something like:
>> | \
>> |____ /
>> with an adjustable slide 'hole' in the middle.
>> What I'm guessing went wrong is that the material hardens and/or
>> shrinks with age.
>> By carefully tweaking the adjustment on this item to allow a mere few
>> thousands of
>> an inch inward... the drive started initializing fine every time.
>> I did not use the drive much after that, so how drive longevity would
>> be effected by
>> the introduction of contaminants into the HDA assembly I don't know
>> (I of course
>> don't have a clean room :-) ).
>> However, if you have a fairly clean space, and can work carefully as
>> such not to
>> stir up contaminants, you may be able to rescue your RD53.
>> Another problem I read of someone having a problem with an RD53 had
>> to do
>> with the brake solenoid assembly needing adjusting as the brake pad
>> was dragging
>> (it is located under the circuit board on the bottom as I recall...
>> no inside the HDA).
> I actually did something similar with my RD53. When I got the
> machine, the drive was dead -- it'd spin up, do nothing for ~30
> seconds and then spin down.
> I wagered that the heads were not moving, probably a stiction problem
> -- since I'd nothing to lose (same as your situation) I took the cover
> off, and while the drive was powered up, I gave the heads a small
> nudge. This got the drive working again. I was pretty pleased with
> myself :). Ran long enough to get 2.11BSD installed on it, and
> everything was sunshine and lollipops until last weekend when it died
As I recall, that was the behavior mine had too... slightly tweaking
Bet if I dig it out of storage, it still works... other than the issue
due to the materials aging), that drive was pretty 'bullet proof'...
> It still spins up, but it never seems to get to a "ready" condition.
> Or at least, that's how it _sounds_ -- it spins up, then sounds like
> it starts to spin down a tiny bit, then spins up again in rapid
> succession. It will do this for as long as I leave it running, with
> no head activity at all.
> So I'd like to get one of the spare PC drives I have running in this
> thing, but nothing's ever that simple, it seems... :)
> (On an almost completely unrelated note, I've noticed that my mails
> take 1-2 days to actually make it to the list. I sent out my original
> mail on Sunday afternoon (11/12) and I didn't see it show up on the
> list (i.e. it didn't show up in my inbox) until Tuesday morning!
> Anyone else have this issue? I know I don't get delays like this
> sending email elsewhere...)
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