To: netnews.comp.sys.dec Subject: Re: Problem with RD53 drives on VAXstation 2000 CC: Boris Gjenero In-Reply-To: <32FF9571.3A77C340@undergrad.math.uwaterloo.ca> References: <32FEA540.54A0309A@undergrad.math.uwaterloo.ca> <32FF9571.3A77C340@undergrad.math.uwaterloo.ca> Boris Gjenero writes: > I concluded that the microcontroller on the drive was shutting it down > because it found a fault. Is there any way to get error codes out of or > run detailed diagnostics on RD53 drives (I don't think the diagnostics > on the VAXstation are good enough--I need lower level diagnostics)? > Does anybody recognize this failure mode? Sounds like you've run into the classic failure mode of the RD53 / Micropolis 1325. Basically, the problem seems to be that there is a rubber bumper inside the drive that the head seeking mechanism rests against when the drive is powered off. Over time, this rubber gets sticky, and the heads can no longer be move. When the drive is powered up, it first spins up and then tries to seek the heads. If it is unable to seek the heads, it spins down again. There are a couple things that you can try, with varying degrees of danger and reliability: - Put the drive in your refrigerator for a few hours. The idea is that the rubber will cool down enough to not be quite so sticky. Unfortunatly, this only seems to be temporary - the drive will almost definitly fail after a few power cycles. You should also be cautious of any condensation that gets on the drive from being cooled down. - Open up the drive and take care of the sticky bumper once and for all. I'll include an outline for this method below. I've done this with two of these drives so far, and each has been running off and on with no problems for the past 2 years. Maybe I'm just lucky so far... (This should be done in as clean a place as you can find, and as quickly as possible to avoid getting dust in the drive. Also, keep in mind that while this worked for me, it is a somewhat risky process and can result in ruining the drive. This is very much a hack, and may not work long term!! Don't say I didn't warn you, etc...) 1. Remove the screws on the top of the drive - some may be covered by the label. 2. Carefully remove the top cover. 3. Locate the head assembly and the rubber bumper. 4. Carefully move the head assembly (ie, do what the drive does to seek the heads). In order to do this, first you must unlock the head locking mechanism. This is a white plastic thing at the bottom of the drive in the large open space. (kind of vague, I know, but it should be clear when you see it.) You will probably have to hold the lock open with one hand and move the heads with the other. The head assembly will probably stick a little bit at first (which is why the drive can't move it!) (now for the really scary part) 5. Cut out a small piece of paper so that it will fit in between the bumper and the head assembly leaving about an inch or so sticking out. The idea here is to keep the head assembly from sticking to the bumper and the paper does this quite well. 6. Bend the paper over and carefully tape it to something that doesn't move. If you can find a better way of attaching the paper than tape, go for it. Who knows what might happen if the tape deteriorates... 7. Replace the top cover and all the screws. 8. Cross your fingers and power up the drive... I've done this to two drives so far and haven't had a single problem with them for almost 2 years now. Now maybe I'm just lucky, so do this at your own risk and only on a drive that you don't care too much about!! Good luck, and let me know if you have any questions! -Jeff