freak@ihlpa.UUCP (Malloy) (05/07/86)
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 waring 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). From inside the Tesseract of Clancy Malloy (ihnp4!ixlpe!freak) ---------------------------------------------------------------------------- | Everyone looked up and realized that we were only tenants of this world; | | We have been given a new lease, and a warning, from the landlord. | ----------------------------------------------------------------------------