Sent to me this morning after horrendous loss
of all my work when my main drive died, by my friend Al. Thought
it was worth sharing..
Assuming that you are prepared to write off the disk, there
are a couple of things you could try. It's important to try them
in the correct order, since they increase in risk until you reach
the point where the disk is effectively destroyed. In no
particular order, they are:
- Verify the disk is being cooled ... a failed fan
is a common problem, and the noise of a bad fan bearing
is often mis-diagnosed as a bad drive.
- Change cables and terminators (cables, SCSI IDs and
terminations are probably the major source of disk
- (SCSI disks only) verify the SCSI termination voltage (both
at the computer and the disk). If the voltage is missing,
try to determine why and fix the problem. If the voltage
is too low, try enabling the termination voltage at both
ends of the cable (this is not normally recommended since
it can lead to a ground loop which increases noise
- Put the disk on a different power supply (usually by
swapping it to another enclosure).
- Try the disk on a different computer.
- If "mechanical" noises are coming from inside
the disk, don't run the disk until you've eliminated the
source of the noise (or verified that the disk can
be run without destroying it).
- Physically remove the disk from all power sources, then
observing proper anti-static precautions, carefully
open up the disk enclosure. Determine whether the disk
can be run with the case open (ie everything is screwed
in tight). Some disks can be run with the case open. If
the disk was making noises, try to determine the source.
DON'T TOUCH THE PLATTER SURFACES! (Or allow anything to
come in contact with them).
- Assuming everything is screwed in tight, turn the disk
over and shake it to see if anything falls out. If it
does, try to determine what it is and where it came from.
If it's an electrical component, chances are you may have
to replace the electronics (with electronics from an
- Examine the platter surfaces for scratches (You will need
a bench light or flashlight for this). If a surface is
scratched by one of the heads (or arms), then that
head is probably toast. Data on that surface is
probably unrecoverable unless you can replace the head
assembly and the scratching isn't too bad. If the
scratching is severe enough to affect the rotation of the
disk, then that arm may have to be bent or cut away to
allow the disk to rotate properly.
- Touching only the edge of the platters rotate the disk to
check for sticky or rough bearings (use something
extremely clean for this, hands aren't a
particularly good choice, plastic (such as plastic wrap)is
generally better but is a major source of static, so
don't let it touch the electronics).
- If the disk appears ok mechanically, then hook it up to
power and turn it on. If the disks don't start spinning,
try giving them a push. If that makes them go, then maybe
the problem is the motor is no longer powerful enough
to start spinning the disk.
- You should be so lucky that the problem is a broken power
lead, but hey, you should check anyway.
- If the problem is the disk bearing (it's sticky or rough),
then you could try an infinitesimally small drop of ultra
fine machine oil on the bearing. This may smooth it out
enough to run the drive long enough to get some data off.
- If the problem is the head stepper motor assembly, then
it is theoretically possible to replace the head and
stepper with an identical unit from another drive.
At a minimum this will require a good assortment of
miniature tools. Given the alignment (and re-wiring)
problems this will introduces, this procedure has a
pretty low chance of success.
- If there are no signs of mechanical problems then the
problem may be with power. Perform a continuity check on
the power and ground.
- If there are no signs of mechanical problems, and you
have power and ground continuity, then the problem may be
with the electronics. Do a comprehensive visual
examination of the electronics. Look for blackened or
discoloured components, examine the traces on the board,
look for signs of heat (melting, balled up solder, curled
traces, etc). If you have an identical drive, then you
may be able to swap the electronics (this may involve
cutting, unsoldering and resoldering wires. Depending on
the drive this may be fairly easy or virtually impossible).
Also, note that drives which use EEPROM for
various parameters may mean difficulty recovering
data even if the drive is usable after the swap.
- Connect the drive to power and check voltages (you will
need a meter for this). Check the electronics board,
the stepper motor, and to the disk motor (assuming you
can figure out where they are and can reach them). Check
the fuses (if you can find them). If there is no power,
you may be able to solder in a jumper wire to bring
in power (or ground).
- In all cases, you probably want a low level disk read/write
diagnostic program to determine the effect of the
changes you make.
I'm certain that I've missed or messed up more than a few of
the suggestions offered here, so take all this advice with a
grain of salt and a pound of caution. And of course, if you
aren't a certified technician you shouldn't ever open up an
electrical device anyway : ) ..