jeff@wdl1.UUCP (Jonathan J Jefferies) (08/26/88)
What information does anyone have on hard disk anti-static contacts. Each of my hard disks: micropolis 1304,1335, Rodime 204e, and Seagate 4096, has a metal contact which is positioned to rub against the disk spindle. My problem is that these things all make noise after the disk reaches a certain age. Apparently there is enough wear on them to create a ridge or set of grooves which create a kind of rattling or rubbing sound. I've found a number of instances where folks have thought their disk was going out due to this racket. One disk repair shop told me that this problem provides them with numerous six pack fixit jobs, i.e. they would fix the disk for a six pack. I suspect though that in some instances they might charge a bit more if the customer was totally unsuspecting. To further confound me, a chap down at Micropolis' repair section told me that Micropolis was going to do away with them because they were superfluos. And in fact he removed them from disks brought in for repair. I did notice however that my latest drive a micropolis 1335 distributed under the CMS label did still have the noisy little begger - perhaps it was built before Micropolis made the necessary engineering changes. The question then is what risks do I run in removing or at least bending them back so no contact is made. The chap at Micropolis indicated that they are primarilly there to remove static and that the spindle bearings or bushings made sufficient contact to perform the same function.
cdold@starfish.Convergent.COM (Clarence Dold) (08/27/88)
From article <3910005@wdl1.UUCP>, by jeff@wdl1.UUCP (Jonathan J Jefferies): > What information does anyone have on hard disk anti-static contacts? > > is that these things all make noise after the disk reaches > > To further confound me, a chap down at Micropolis' repair section > told me that Micropolis was going to do away with them because > they were superfluos. And in fact he removed them from disks > These spindle grounding brushes may indeed by superfluous on newer drives, and there may even be drives that don't need them where the vendor continued to supply them, while also doing long term testing without them. I wouldn't remove one from an existing drive, since quieting them is usually not difficult. I have been successful with two methods: 1) Rather than bending it back so it doesn't touch, what you need to do is bend it forward so that it makes better contact. The vibration is caused by surface irregularities. Slightly more pressure will dampen the vibration, making up for the wear that the carbon brush has suffered. You will need to loosen either the spring, or the entire board, in order to bend it forward. 2) Our system mounts drives on edge, which heightens this noise problem. Seagate's fix for us was to apply a small strip of adhesive backed rubber to the spring arm, dampening the oscillation. I've seen mention on the net of using a dab of silicon rubber or contact cement for the same purpose.