New SE and Miniscribe deep-dive

[PB145B]

I found this nice earlier model SE on eBay for a great price. I was really hoping it would have the squirrel cage fan/blower, but it’s about a year newer that I thought it was, so it does not. I plan to swap the analog board out at some point for an older one that does. I’ve heard they move a lot of air, and I just think they are really interesting. And I’m not really bothered by some fan noise.

Here’s some pics of the unit:
 

Very little yellowing. Looks great. It does have the older 1986 revision motherboard, so that’s pretty cool. And yes, I did remove the battery. 
 

This machine had the original Miniscribe 20MB drive (red LED), which had a VERY stiff stepper motor. I put a drop of oil on it, which helped a little, but the issue is that only gets the outer bearing, not the inner one.

So, what did I have to do? COMPLETELY REMOVE the stepper motor to gain access to the other bearing! 
 

Here’s some pics of the drive including the stepper motor removed from it:









So I got the stepper motor moving pretty freely after oiling the inner bearing, and then reinstalled it. Of course I had the open the drive also to keep the heads in the right position.

Put it completely back together, tried to format it with HDSC Setup and the Micronet utility, and neither would format it. Obviously the cylinders got misaligned while messing with the stepper.
 

So I connected it to my SE/30, which I have FWB Hard Disk Toolkit on, and that allows for a low-level format. I tried that, and it failed a little ways through, but it must have realigned it, because Micronet was able to successfully initialize it after that! The drive is now back in the SE and boots to System 6.0.8 just fine now. I will be putting System 7 on it tonight though.

So the hours I spent on this Miniscribe payed off! Really is nice to see this drive live again. Most would have probably trashed it for a SCSI2SD, and I do like those, but I think the mechanical drives (especially these stepper-drives ones) should be saved when possible.

I have also bought another drive I plan to use in this machine, which hasn’t arrived yet. Surely some nice high-capacity drive, right? Nope, it’s the infamous Rodime RO652, that was used in the very earliest SEs. Rodimes are notoriously unreliable, but I’m going to try and revive this one once I get it. The Stepper may need the same treatment. These are my favorite as far as the “sound” goes. A Rodime doesn’t sound like anything else. It’s also pretty cool that these were the very first 3.5” hard drives.

Anyways, that my SE! My THIRD SE...

 

[LaPorta]

I really want to develop a good method for fixing these drives. Someone had a good particle chamber to work on them that they made themselves. I need to make something like that.

 

[davidg5678]

I really want to develop a good method for fixing these drives. Someone had a good particle chamber to work on them that they made themselves. I need to make something like that.

Have you seen this video before? The design uses a vacuum and HEPA filter to remove dust from a small, filtered chamber. It probably is not perfectly dust-free, but I'm sure it would be a vast improvement over working out in the open. I'm not totally sure if this is really true, but from what I have read, it sounds like older hard drives may be more resilient to dust than newer ones anyway, so this design may be a good way to safely resurrect some broken disks.

 

[PB145B]

I really want to develop a good method for fixing these drives. Someone had a good particle chamber to work on them that they made themselves. I need to make something like that.

Yeah, maybe for the newer drives, but for these low-density stepper drives it’s really not necessary. It would take quite a bit of dust to kill one like this.

 

[PB145B]

Look at this battery that was in it:



“Made in West Germany” You know that’s old...

 

[techknight]

And it probably still had a charge. 

 

[PB145B]

And it probably still had a charge. 

It actually did not. I was surprised, because the Varta from my IIgs actually still read around 3.1 volts!

 

[Bendix]

Incredible! Good Job. just took my old 20 MB Miniscribe, which would not spin up any more, did, what you did, and now I can write to it. The FWB stopped half way through low level format like you describe with an error (actually just a stop sign hand and OK) but I could create a partition and copy system 7.1 to it. Only thing is, when I boot, the stepper motor make a noise like moving forward/backward for a minute or more and then the drive ist not mounted. I can mount it with FWB manually and then it is fully operational but it takes this noise time off, when the SCSI bus ist initiated. So obviously I cannot boot from it.

Hmm, still some stepper motor misalignment?

 

[PB145B]

Incredible! Good Job. just took my old 20 MB Miniscribe, which would not spin up any more, did, what you did, and now I can write to it. The FWB stopped half way through low level format like you describe with an error (actually just a stop sign hand and OK) but I could create a partition and copy system 7.1 to it. Only thing is, when I boot, the stepper motor make a noise like moving forward/backward for a minute or more and then the drive ist not mounted. I can mount it with FWB manually and then it is fully operational but it takes this noise time off, when the SCSI bus ist initiated. So obviously I cannot boot from it.

Hmm, still some stepper motor misalignment?

Thanks! 

My drive does make some “additional” noises now when booting, but it doesn’t seem to affect it.

Have you tried formatting it with Micronet? I initially couldn’t boot from it after formatting with FWB, but was able to format/partition it with Micronet 4.0 afterwards. Let me know if you can’t find the utility online, and I’ll post it on here.

 

[Bendix]

I did a quick (not thorough) search and cannot seem to find it. It would be great, if you could post it here. I am really excited about the progress with the Miniscribe 8425SA so far, had already singled it out for the next electronic litter dump at our community. Mine is exactly the same model like yours, the only difference is in the field "Unique", where the sticker says 17 on yours and 07 on mine.

 

[PB145B]

I did a quick (not thorough) search and cannot seem to find it. It would be great, if you could post it here. I am really excited about the progress with the Miniscribe 8425SA so far, had already singled it out for the next electronic litter dump at our community. Mine is exactly the same model like yours, the only difference is in the field "Unique", where the sticker says 17 on yours and 07 on mine.

Here you go!

View attachment MicroNet™ Util v4.0j.zip

 

[Bendix]

Thank you very much! Alas the Miniscribe has stopped working again. After cooling off it did not spin up at first and when it finally did, it was no longer recognized on the bus. Tricky...

 

[PB145B]

Thank you very much! Alas the Miniscribe has stopped working again. After cooling off it did not spin up at first and when it finally did, it was no longer recognized on the bus. Tricky...

No problem! Ah, if your drive is having stiction problems (heads freezing to the platters) then it may be near impossible to fix. Only way I have heard of people fixing stiction is to remove the heads and gently clean them, but it would be tricky to remove the without destroying something.

 

[Franklinstein]

Apparently the squirrel-cage fans also sometimes caused screen jitters in addition to being loud, i assume because their EM field was greater than anticipated during design. So keep that in mind if you're having odd display problems with a squirrel-cage unit.

Stiction in hard drives is caused by the highly-polished surfaces of the head sliders and the platters coming together, sometimes for a very short period of time. The old Sony SRD series of drives were notorious for this even when relatively new, but other drives experienced the problem as well after a while. Modern (1996ish?) hard drives mostly eliminated it by laser texturizing the landing zone of the platters. Perhaps using a polishing pad of some sort on the head sliders would provide enough texture to keep them from sticking without making them too rough? 

Also, contact start/stop (CSS) hard drives have only a finite number of start/stop cycles (usually 50-100k) before the head sliders and the landing zone on the platters start to wear on eachother to the point that one or both of them begin to break down and contaminate the media. I have pictures somewhere of a drive that did this in a grand fashion (a 4GB Quantum unit, I think), basically filling the HDA with a fine powder and rendering the drive totally unusable. If you use any sort of power-saving hard drive spin-down settings, on a desktop or laptop, you may want to disable this if you want your drive to last. At the same time, you don't want to run it 24/7 or you'll likely wear out the spindle bearings. I'd suggest if you use it every day, start it up before use and shut it down when done for the day; this should spread out the wear to keep it alive as long as possible.

The newer (2003ish, earlier for notebook drives) ramp-loading head drives have more start/stop cycles but their ramp load cycles are also finite, usually on the order of 100-200k cycles (markedly fewer for emergency/power loss unloads, which can be as low as 30k) before contamination is likely. It's best to try to use the APM settings to set the drives to idle-unload the heads as infrequently as possible, which will greatly extend drive lifetime. Unfortunately legacy Macs have no utilities for changing either the APM or AAM settings on a modern drive, so you'll have to hook the drive up in a PC and run the appropriate utility there to set them before putting the drive into your Mac.

One of the things I hate about mid-90s Macs was the way they spun the hard drive up and down repeatedly if they couldn't find an OS, and also how some would spin the drive down for a restart only to immediately spin it back up. Both of these actions accelerate wear on the drive and are totally unnecessary.

 

[PB145B]

Apparently the squirrel-cage fans also sometimes caused screen jitters in addition to being loud, i assume because their EM field was greater than anticipated during design. So keep that in mind if you're having odd display problems with a squirrel-cage unit.

Yeah, I’ve heard of that, and have to wonder if it has anything to do with the horizontal neck board, which puts it closer to the fan, versus the newer vertical neck board.



 

That squirrel cage fan fascinates the hell out of me. Don’t know why.

 

[PB145B]

Here’s a pic of it running.



That red LED looks great, doesn’t it? The amber on the newer ones look good, but the red is definitely my favorite.

I did also update it to System 7.0.1, which I’m really liking on here. For laughs, I’d like to temporarily put a stripped-down copy of 7.5 on this Miniscribe just to see how it would handle running on a 20MB stepper drive.

System 7.5 itself can actually be decent on an SE,  as long as you can live with the 4MB memory ceiling, but you need a fast hard drive to make it usable.

I should also mention I did clean-out and re-lubricate the 800K floppy drive, and it works great now.

I have not recapped the analog board or anything yet, but that’ll come eventually.

 

[PotatoFi]

I really want to develop a good method for fixing these drives. Someone had a good particle chamber to work on them that they made themselves. I need to make something like that.

I did one with 3D-printed parts. If you want a set, I'd happily print them off and send them your way. I have two MiniScribes in my office that don't work (one blew a capacitor yesterday, as you know) and would like to see a repair method as well.

 

[PB145B]

Scanned the Miniscribe with Norton Disk Doctor, and it found 3 bad blocks that “could not be repaired.” I’m assuming it didn’t have any spares to reallocate, and just marked those as “unusable.” The drive is still working fine either way.
 

@PotatoFi Great work on that clean box! Looks good. And once again, amazing work reviving that SE FDHD. I love to see ones like that come back from the dead! Seeing your thread is actually what made me search eBay for SEs, which led to me buying this one, so I blame you for that.   

 

[PB145B]

Oh boy, I finally got the Rodime RO652 I ordered from Canada, and actually got the damn thing working!






Amazing piece of equipment, isn’t it?

This one came from an early Macintosh SE (I know because it still had the SE bracket on it with the red LED. I just had it removed for testing in my external case.

It just wouldn’t work at first and would actually crash the computer if you attempted to copy anything to it, but after about an hour of warming up and about 6 low-level formats, it works almost 100%! Still gives a errors when writing every now and then, but it’s getting better the more I use it, so I think this will be going in the SE. I’ll put the 20MB Miniscribe in the external case so I can keep using it as well!

I copied System 7.0.1 on it, and it does boot on my PowerBook 170, which is very promising.

Next step is to try it out in the SE!