VOGONS


First post, by siralec

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Hi,

I have recently aquired a 286 lunchbox-computer (integrated 640x200-monocrome display) whose MFM-hardrive has some serious problems.
The drive is an Microscience HH-1090. It is connected to a wd1003-wa2 full length 16bit MFM-HDD and FDD-controller. 286-board is a PAT 7.2. (printed on PCB) seemingly produced by T.M.C. (on POST-screen).
CMOS-battery is dead and the BIOS of this board does not let me enter the drive parameters manually, so i chose a type which nearly matches the parameters of the HH-1090.
The problem with the HDD is, that it spins up on powerup but when it tries to move its heads, it produces a single "clacking" noise and immediately spins down afterwards and drive initialization on POST fails. behaviour is the same if drive is only connected to power (MFM-cables disconnected).
I think, the mechanism, which moves the drive heads is stuck. Is there a way, (short of opening the drive) to make the HDD working again or should I let it rest in peace?

Alex

Reply 1 of 16, by computerguy08

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The oil in the stepper motor bearings might be dried out. If you have access to the stepper motor, you can try adding a drop of oil.

Here is Adrian's video for more details on this issue.

Reply 2 of 16, by pentiumspeed

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Back in the day, I had lots and lots of Tandon/WD of stepper drives and Miniscribe with stepper always failed both that share same basic rack and pinion gear actuator. That is the real reason.

Both failed same way for one reason, both did not use split lock washers and they did not use thread glue lock (loctite), with time the rack which is a rack gear with machined teeth into a square bar of alloy metal with two holes drilled through to mount rack onto slider table, there were no locating pins either to maintain alignments. Just two screws secures the rack to the slider table that slides on rails that heads is bolted onto. And there is play too when that two screws loosens up.

With time that rack block starts to slide and mis-align as pair of screw loosens up from the stepper vibrations.

In clean room you can save these by align just right when hard drive works again and tight, take one screw out and apply loctite to threaded part near the threaded end and replace the screw then torqued. Do the same with other screw.

Seagate 2 and 3 platters 5.25" drives is very very sensitive to mechanical shock because the steel rod that is the spine for bearings and spindle hub that platters mounts on is very soft metal which bends easily then platter wobbles badly. I wished they used tempered or spring steel so that will not bend.

All my computers point on never had the tandon/WD stepper, and no miniscribe either. I was early adopter of voice coil hard drives, my first one was 80MB ST1102A in 1993 in 386DX 25 machine was paid with my work money, when still a high school student. When I learned about head parking ramp technology incorporated into 3.5" drives that 2.5" normally have, I bought them at first opportunity.

Any hard drives that can't keep cool tend to fail quick due to too much heat baked into hot platters degrades the coating then wears off quickly where heads lands on and take off when HD is so hot they get stuck.
Ones are cooler hard drive by design lasted long time and did not stick. I meant cooler running hard drive by design and the ones that run hot was kept cool from forced air cooling did not stick.

I like to do failure analysis on failed stuff. Reason for this, I collect failed stuff and learn about them and I was working with places that handled lot of computer lends well to plenty of broken stuff to take apart and play with them too.

Cheers,

Great Northern aka Canada.

Reply 4 of 16, by Horun

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Yeah hate old stepper MFM/RLL drives. It is probably beyond repair.

Hate posting a reply and have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. 🤣

Reply 5 of 16, by maxtherabbit

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pentiumspeed wrote on 2020-04-01, 23:22:

When I learned about head parking ramp technology incorporated into 3.5" drives that 2.5" normally have, I bought them at first opportunity.

when did this go mainstream with 3.5 drives? that's actually something I've been wondering about lately

Reply 6 of 16, by pentiumspeed

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Looong ago, when IBM/Hitachi announced that around Deskstar 7K250 series. Other brands came on with this concept later on.

Cheers,

Great Northern aka Canada.

Reply 7 of 16, by maxtherabbit

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pentiumspeed wrote on 2020-04-02, 01:55:

Looong ago, when IBM/Hitachi announced that around Deskstar 7K250 series. Other brands came on with this concept later on.

Cheers,

that's much later than I would have thought, 250GB was pretty mature in the lifespan of IDE drives

Reply 8 of 16, by pentiumspeed

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Back then I purchased Hitachi 320GB SATA based on 2 platter, 4 head 500GB chassis, two hard drives and they did have ramp parking. still good after 8 years of full time use. Now stored.

Cheers,

Great Northern aka Canada.

Reply 10 of 16, by pentiumspeed

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Dropped hard drives is junk regardless of brands. Not what you are trying to implying at.

Cheers,

Great Northern aka Canada.

Reply 12 of 16, by maxtherabbit

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there are two different failure modes from hard drive shock - 1) head crash 2) physical damage to moving parts from impact

1) can be eliminated by the parking ramp but 2) is always a possibility

Reply 14 of 16, by Cobra42898

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I knew a guy who used to keep a small rubber mallet and would give the drive a whack from the side when they would stick like that. he swears he did it to several of those old mfm drives and it worked like a charm.
of course those were not drives that were dropped or suffered head crashes, so ymmv.

Searching for Epson Actiontower 3000 486 PC.

Reply 15 of 16, by Anonymous Coward

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Any MFM hard drive must be 30-40 years old at ths point. Although some of them were pretty reliable, they are all now decades beyond their projected life spans. I personally wouldn't bother.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 16 of 16, by siralec

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Hi,

sory for late answer.
Thanks for your tips. Unfortunatly this drive does not have its stepper motor easily accessible from the outside. But i have at least a partial success in getting this 31 years old bugger (mfg date January 1989) to get detected and somewhat working.
After some power cycles i could get the stepper motor to "break loose" and get the drive initialized in bios and also access some data on it. It has an install of DR-DOS on it and it was seemingly used at a pharmacy. Using Spinrite i was also able to determine the drivetype (1024 cylinders, 7 heads 17 sectors), drive was setup with. In general the drive produces very loud but not too unhealthy sounding noises on disk access.
I wanted to use Spinrite to check how healthy the disk is, but unfortunatly on Spinrites checking of data rate to drive, it hang up, and i had to powercycle the machine. Afterwards it also took two powercycles for the drive to be accessible again.
But I am still amazed how robust this old harddisks are.