On Fri, 23 Feb 2024 at 19:01, r.stricklin via cctalk <cctalk(a)classiccmp.org> wrote: Yikes, so that's an "open the lid" situation, bear? Any "how to" advise / docs / anecdotes out there as I begin searching?

I wonder if the XT2180 uses the same mech as the XT1140. That thing's initial seek would wake the dead.. --Chuck

Thanks Rick for clarifying my somewhat ambiguous description of how to dislodge a stuck voice coil mechanism. On Sat, 24 Feb 2024, 12:13 pm Rick Bensene via cctalk, < cctalk(a)classiccmp.org&gt; wrote:

Unsticking stiction is different than dislodging a stuck actuator. Stiction is where the heads resting on the disk surface resist the torque of the spindle drive, causing the drive not to spin up. Generally it is caused by weak driver transistors in the spindle drive such that the spindle motor does not generate sufficient torque to overcome the static tension on the disk caused by the numerous heads sitting on it. This didn't happen on drives that retracted the heads either completely off of the disk surface, or had a ramp mechanism that raised the heads off the surface when the heads were retracted. The retraction would occur at power off when a large capacitor was discharged across the voicecoil with enough energy to pull the heads to the parking position. However, some drives actually had a dedicated landing zone on the disk surfaces where the heads could gently settle down (land) onto the disk surface as the platters spun down. It was this type of drive that tended to have issues with stiction. Other cases where stiction could become a problem is in situations where the power-off retract didn't work properly, leaving the heads in contact with the disk surface when they weren't supposed to be. In these situations, if the stiction was cleared by rapping the drive the right way, data damage could occur. In the case of stiction where there is a landing zone, since there's no data/servo information in the landing zone area, causing an abrupt acceleration in the correct axis could dislodge the heads, allowing the drive to spin up properly. So, rapping them with a hammer was a solution for these cases, though I typically used a small-sized dead-blow rubber mallet rather than a hammer, as it wouldn't induce as much resonance as rapping the HDA case with a metal-headed hammer. Also, I managed to use a variant of the "twist" method to clear stiction. I would hook a power connector to the drive, with a switch that switched the +12 and +5 power. I would hold the drive in one hand, and the switch in the other. I'd throw the switch to the ON position, and at the same time, give the drive a quick twist. The twist would accelerate the platters just enough to overcome the stiction such that the spindle drive could start up properly. I'd let it run long enough to warm up, then shut it off, and quickly hook it up to the archival system, and it'd properly spin up and I could get the data off. I also used the hammer method to release stiction. Another trick was for drives whose read/write amplifiers (which were typically situated within the sealed chamber, thus not replaceable except in a clean-room facility) had become flakey, and the drive would start getting lots of I/O errors. I would take the drive and put it inside a large ziplock bag, along with a bag of desiccant(this part is really important to suck up moisture in the air in the bag), and a small battery-powered digital thermometer. I'd put it in the freezer until the drive had reached roughly 42F, and then take it out, and immediately hook it up to an archival system and power it up while it was still cold. This would allow me to get the data off without I/O errors as long as I could get what I needed before the drive warmed up enough that the weakness in the amplifiers again became a problem. I found out about this trick somewhere on USENET many moons ago. It worked for me a number of times. I can't say that it'd work on anything more recent than /early/ 3.5" hard disk drives, though. Newer technology drives have such tight tolerances that the cooling might cause shrinkage that could cause head crashes, so take heed. -----Original Message----- From: Bill Gunshannon via cctalk [mailto:cctalk@classiccmp.org] Sent: Saturday, February 24, 2024 6:10 AM To: cctalk(a)classiccmp.org Cc: Bill Gunshannon &lt;bill.gunshannon(a)hotmail.com&gt; Subject: [cctalk] Re: RD54 Maxtor XT-2190 w/one long meep Back in the day when these disks were common I used to elicit a good laugh from my boss when I got out my little mallet and smacked the side of the drive. Stiction was the problem but a good hammer fixes anything. And, no, I never had it damage a disk. I guess it was all in the technique. :-) bill

It is quite possible to put a touch of watch oil on the shaft of an older drive (without opening it) to quiet the bearings and re-libricate the grease. I'm still running RD54's and RD53's without much of an issue, firing them up every few months seems to keep them happy. Same for RD51's and RD50's. By the time you get to the full height Hitachi ESDI and CDC half height ESDI drives they just seem to work without complaining. No issues there. C (I love RD53's: They were the biggest disk you could run in a Pro/350-380 and I have opened them to free stuck heads. They have an absolute air filter in there which filters the air as it is sucked into the spindle to be blown out over the heads, so to be honest I think you can open and close them without the world coming to an end. Just don't sprinkle salt from a shaker into the drive to see if the heads will FINALLY crash (yes, eventually that will do it). On 2/25/2024 10:09 AM, Sellam Abraham via cctalk wrote:

Here’s some info. https://www.stason.org/TULARC/pc/hard-drives-hdd/maxtor/XT-2190-155MB-5-25-… It does sound like it can’t seek. Maybe a jumper incorrect? Sent from my iPhone On Feb 26, 2024, at 14:29, Jacob Ritorto via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: Thanks for the good ideas and convo everyone. Now please do note that I can definitely hear motor/platter spinup happening so it's definitely not "heads stuck to platter" stiction. I hear the lock unlatch and I *think* I even hear the heads load and fly (comparing what I hear on this drive to other drives I've actually seen the guts of in flying action) so I substantially doubt it's "arm stuck to lock pad goo" stiction. So we've made it through a lot of the powerup sequence and the problem is at the final part - the track scan up and back down the surface - the phase when the signature "...blearrnnnnt-meeeeeelrp..." happens :) And yes I believe from memory that XT-2190 is supposed to make the same track scan noise as the XT-1140 (I have an XT-1140 running perfectly as a fake RD54 in another pdp here). So could my behaviour of being hung at the final phase - the track scan noise - be the result of a lost servo track? Thinking about that, didn't someone on this list kill an XT-2190 recently by taking an outrageous magnet to it? Did you get the same track scan failure as I'm getting? Confused electronics on the PCB? Something else? Where would one begin diagnosing this particular problem? I did try the wrist twist torquing thing. And lightly whacking side of housing with palm of hand during track scan noise. Declining to do that hard, tho. Powered off and back on (to retry) probably near a hundred times now. Heated it gently in front of our forced-air furnace duct until comfortably warm to touch - probably near 105 F. All these produced absolutely zero behaviour change. thx jake

Get a sheet of glass. In a not too dusty area (hint A/C has filers usually) gloves on Top off glass on - all will be revealed. Rod - Digital Equipment Corporation  1975 - 1985 On 27/02/2024 03:50, Chris Zach via cctalk wrote: