Micropolis 1325/RD53 spinup/down problems
Bruce Mitchell
I have a stack, a reasonably _big_ stack, of Micropolis 1325 / DEC
RD53 disk drives. All of them seem to have the same problem, which
is as follows:
The drive unlocks the spindle, starts to spin up, reaches what I am
guessing to be operating speed, then either holds that speed for a
few seconds or spins right back down.
The problem must be fairly common in these drives if I can collect
20 of the beggars in my basement. Does anyone have schematics, a
service manual, or just plain suggestions as to how I might attack
this problem?
Thanks in advance.
/s Bruce R. Mitchell
mi...@cvfn.org
Don Taylor
In message <53505v$k...@news.intur.net> - Bruce Mitchell <mi...@cvfn.org>5 Oct
In my experience over the last 8 years that is THE failure mode for
the 1302/1304/1325 series of drives. I talked to a drive repair shop
about this particular model of drive and they said they were aware of
the problem. They claimed that they had been able to recover these
drives by opening the drive in a clean room and tightening a bolt that
gradually worked it self into a different position. When this change
took place the drive was unable to find the servo within the time limit
at power up and would shut it self down. As it spun down the logic
would then take over and try to start the drive back up.
I stumbled across a trick get some of these drives up. If you put the
drive in the refrigerator and cool to an appropriate temperature and
then pull the drive and immediately try to power the drive up. Getting
it too cold seems to not work and the behaviour is the same. If the
drive won't come up try just a bit more cooling. I have successfully
managed to get failed drives up and spinning and been able to use them
until the power would fail and I had to start all over. It does seem
that after doing this repeatedly that it might get harder to make them
work.
This information was passed along to technical support at Micropolis.
The guy sounded serious when he said he would file this info and pass
it along to future customers who were in trouble. I don't know whether
he did this or not.
Hope this helps
Bill Rothanburg
Bruce,
What's the point? According to my refs, this is a 71 Meg 5.25" full-high
drive. Working, they might be worth $10.00 each at a swap meet. Dead they're
probably worth $5.00 as high-tech doorstops. Or contribute them to an
artificial reef project.
Bill
In message <53505v$k...@news.intur.net> - Bruce Mitchell <mi...@cvfn.org>5 Oct
1996 06:45:19 GMT writes:
:>
:>I have a stack, a reasonably _big_ stack, of Micropolis 1325 / DEC
:>RD53 disk drives. All of them seem to have the same problem, which
:>is as follows:
:>
:>The drive unlocks the spindle, starts to spin up, reaches what I am
:>guessing to be operating speed, then either holds that speed for a
:>few seconds or spins right back down.
:>
:>The problem must be fairly common in these drives if I can collect
:>20 of the beggars in my basement. Does anyone have schematics, a
:>service manual, or just plain suggestions as to how I might attack
:>this problem?
:>
:>Thanks in advance.
:>
:>
A.R. Duell
william.r...@worldnet.att.net (Bill Rothanburg) writes:
>Bruce,
> What's the point? According to my refs, this is a 71 Meg 5.25" full-high
>drive. Working, they might be worth $10.00 each at a swap meet. Dead they're
>probably worth $5.00 as high-tech doorstops. Or contribute them to an
>artificial reef project.
One good reason for repairing older hard disks is that it's getting very
difficult to find drives with the ST506/ST412 interface. And some older
machines _require_ that interface - you can't go and get a SCSI or IDE
card for a classic PERQ or a DEC Pro350.
>Bill
>In message <53505v$k...@news.intur.net> - Bruce Mitchell <mi...@cvfn.org>5 Oct
>1996 06:45:19 GMT writes:
>:>
>:>I have a stack, a reasonably _big_ stack, of Micropolis 1325 / DEC
>:>RD53 disk drives. All of them seem to have the same problem, which
>:>is as follows:
>:>
>:>The drive unlocks the spindle, starts to spin up, reaches what I am
>:>guessing to be operating speed, then either holds that speed for a
>:>few seconds or spins right back down.
>:>
>:>The problem must be fairly common in these drives if I can collect
>:>20 of the beggars in my basement. Does anyone have schematics, a
>:>service manual, or just plain suggestions as to how I might attack
>:>this problem?
This is, alas, a stock fault on these drives, and I _think_ it's due to
the head assembly sticking to the end stop inside the HDA. It's not
normally an electronic failure. The following procedure sometimes gets
them to spin up so you can recover data from them :
1) Flip the drive over, undo the 2 screws holding the logic board down,
swing it up
2) Unplug the 2-wire flexiprint cable from the motor/servo board (on the
HDA). This is on the right hand side, looking from the back of the drive
with it upside down.
3) Apply power. The motor should start, get up to speed and remain up to
speed
4) Plug in the flexiprint and hopefully the heads will find track 0, and
the drive will go ready.
5) Back up the data :-)
BTW, if anyone has the service manual/schematics for these drives, I'm
looking for a copy as well. AFAIK, it did exist at one time...
--
-tony
ar...@eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
Bill Rothanburg
Bruce,
OK, given that it is important to repair these drives, you might try
contacting Bob at ACR Computers. (954) 480-9243. He may be able to assist
you. Note that Bob is expensive - but a bargain. An he is honest.
Bill
In message <53505v$k...@news.intur.net> - Bruce Mitchell <mi...@cvfn.org>
writes:
:>
:>I have a stack, a reasonably _big_ stack, of Micropolis 1325 / DEC
:>RD53 disk drives. All of them seem to have the same problem, which
:>is as follows:
:>
:>The drive unlocks the spindle, starts to spin up, reaches what I am
:>guessing to be operating speed, then either holds that speed for a
:>few seconds or spins right back down.
:>
:>The problem must be fairly common in these drives if I can collect
:>20 of the beggars in my basement. Does anyone have schematics, a
:>service manual, or just plain suggestions as to how I might attack
:>this problem?