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1993-07-25
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Hard Disk Noise - From The Internet
From: Malloy <freak%ihlpa.uucp@BRL.ARPA>
Newsgroups: net.micro,net.micro.att,net.micro.pc
Subject: Hard Disk Noise Results
Message-ID: <1332@ihlpa.UUCP>
Date: 7 May 86 00:14:55 GMT
Xref: seismo net.micro:15310 net.micro.att:1259 net.micro.pc:8643
To: info-micro@brl-vgr.arpa
A few weeks ago I posted this message requesting help for my 10Mb
hard disk.
> HELP!!!! HELP!!!! HELP!!!! HELP!!!! HELP!!!!
>
> I have a 10 Mb CMI hard disk on my PC, mounted in an external cabinet.
> The HD never goes "out of service", but it makes a strange sound.
> Shortly after power up and then every once in a while after that, there
> is a very strange whining sound. It has never interfered with the data
> on it, but I worry that there is something wrong. Can something be oiled
> or what?
>
> Please send mail, I will post a summary.
I have gotten many responses and almost as many solutions. Here
then are the possible solutions to the problem. I am still unsure as
to which I will try, but... To the people who responded, Thanks. To other,
with same problem, here are some of the possibilities.
This is the Summary:
This noise is often caused by a slight rubbing of the drive's
spindle brakes. It usually requires a radical disassembly of the drive on
a clean air bench to adjust ('though CMI may have done it differently).
If the noise is not excessively annoying, your data is okay. If the
noise is excessively annoying, your data is still okay but components in
you drive's brake mechanism are wearing out a little faster than normal.
=====================================================================
I don't know specifically about the CMI drives, but many 10Mb
drives are constructed with a copper spring which contacts the motor
spindle to remove static electricity. The spring usually has a finger
in the center which contacts the spindle, and is surrounded by copper.
This spring can resonate, creating a whine or a squeal. The fix is to take
some silicone rubber and put two drops where the finder joins the rest of
the copper:
___________ #################
| #* #
| ############# #
spring side view #* #
#################
top view - apply silicone to '*' areas
=====================================================================
Sounds like you are losing a bearing in the spindle. If this is
indeed the case the drive will totally fail in 6 months to a year. I
suggest you back it up regularly.
=====================================================================
I have the same setup and same noise on my Shugart 606 8 MByte
drive. I was told by a very knowledgeable hardware guy that it is some
bushing or other that is not critical and only annoying. It seems to be
lessening with use.
=====================================================================
I am sorry to say that the whining sound is just the nature of the
beast. We have dozens of hard disks at work, some whine all the
time, some whine intermittently, other don't whine at all. The whining
seems totally unrelated to whether the drive will fail or not. I don't
think there is anyway to oil the drives, since they are sealed and breaking
that seal is inviting trouble. If it gets bad enough, you might want
to consult the manufacturer for their recommendation.
=====================================================================
I have an Eagle 1630 (XT somewhat-compatible) that made an
intermittent whining noise. I don't know whether or not it was a CMI,
but that sounds familiar. Fortunately, it was still under warranty (by a
matter of weeks) and so I took it in for work. Not after taking
it out to look at it. No, there is absolutely nothing to be oiled -- it
is undoubtably a sealed unit, bearings and all. I believe that it had a
bearing going out, which I would imagine could be dangerous to data if left
to wear. If particles didn't start flying around, slowing the disk
rotation would eventually cause problems. Better get it fixed -- and do
some backups.
=====================================================================
When I used to work computer repair, we had people complain of
such noises about three or four times a day. Every time the problem
was caused by the static ring on the bottom of the Hard Disk (the ring in
the center of the bottom of the drive that touches a ball to drain
off rotational static). Anyway, the fix to this problem is to lightly lift
the ring off of the ball and let it snap back. I have never seen this fail
and the drive will shut up for a long time. If it doesn't work then you
haven't snapped the ring hard enough.
=====================================================================
What you are probably hearing is the disk finding a bad track or
sector. This sector has already been mapped out by the format procedure,
but the controller must be reset to find home. The reset uses the slowest
step rate for the disk drive head motor, thus the strange growling whine.
=====================================================================
Not to worry - I've used these drives myself, and that "whining"
is just the drive recalibrating itself, occasionally.
=====================================================================
Do you have an AT&T 6300 with the "sidecar" expansion disk, the
baby that is attached to the left-hand side of the AT&T CPU box?
If so, the problem is pretty well known, at least here at AT&T
International, and can be fixed pretty easily:
Open up the sidecar and take a look at the disk. You can put the
entire unit on its side, so that the expansion box is on top, and then
the disk drive will be turned 90 degrees, back to the horizontal
orientation that most of the world uses. On the top, there will be a
small metal arm with some kind of carbon brush under it. As the disk turns,
this brush is making contact with the surface underneath it (not
actually the disk platter, of course, but it turns with the disk anyway).
It is not actually supposed to make contact with the disk; it just does.
Hence the noise.
We fix these things regularly by taking a small screwdriver and
prying the little metal arm up (it is slightly sprung) so that it remains
off the surface below. If you want, you can boot your machine this way,
with the cover off the expansion box and the CPU sideways. It should boot
normally, except that there should be no noise. If the noise starts back
up, you have not pried the little metal arm up enough. Go back to the
start of the paragraph and try again. If there is no noise, replace the
cover and turn the thing back the way you want it (turn it off first).
--- Editor's Note: My Seagate ST-4096 has recently been making some noise
as well. Following the instructions above, I was able to
reduce the noise created by the "arm" by quite a bit. This goes to show you
that "ancient" tips and data still have uses to this day.
Todd.