Thanks to the resourcefulness of my viewers, I've been pointed to the service manual for the ST-225! I love this community. https://www.minuszerodegrees.net/manuals/Seagate/Seagate%20ST225%20-%20OEM%20Manual%20-%20Oct85.pdf

Adrian sets out to make a video showing how unreliable MFM era drives are. Every drive doesn’t work. Message received Adrian 😁👍🏼👍🏼

You should save the logic boards from the dead drives, so that if you see the same models in the future, you can swap them to see if that fixes any problem. At the very least there might some valuable parts you can reuse.

With the ST225, try pulling the PCBA off it and cleaning the contacts that connect the HDA to the PCBA. If I recall correctly there will be spring connectors for the hub motor and an elastomeric connector for the heads. Worth pulling the elastomer out, cleaning with IPA, and flipping it so the "squished for 30 years" parts are no longer aligned and it makes slightly tighter contact.

Whether the hardware works or not it is never a failure when you learn something useful, I call this a success with a twist.

Those platters are made of the purest aluminum of any mass produced parts ever made. The oxide coating is so thin as to be completely invisible. A pigment is added only so that in manufacturing they could tell the coated platters from the raw ones. In later years there was no need to add the pigment, so the platters appear to be bare metal. The surfaces are also extremely flat, usually within 25 microns across the entire surface. A hard drive platter makes an extremely nice signalling mirror, for primitive hiking. The sun's reflection will be about the size of the platter over considerable distance and you can look through the center hole to aim the reflection.

Enjoyed seeing inside the drive while it was spinning and moving the head. Fun stuff!

It was great hearing the sounds of those old drives, brings back memories. I still have my original SCSI version of the ST-225 (the ST-225N), would be great to spin it up and dig through all the old '80s software and long forgotten programming efforts.

Back in the day, Micropolis Hard Drives were mostly large, high volume disk drives. They were known for being noisy, but were usually larger (storage space wise as well as physically) than other drives. Seagate MFM drives were some of the most reliable back in the 80's. They were also the largest producer of MFM drives at the time. Miniscribe were primarily hard drives used in business. Western Digital had a few, but no one could compete with Seagate. Things changed when IDE took over. Western Digital and Maxtor took over the top 2 spots.

I have recovered data from countless mfm drives by doing exactly what you said not to do. When it's not spinning up what are you gonna hurt by opening it. Unless it's super critical data that can't be risked, but then you would use your back up! As you said these were not reliable drives and that was a known fact, so back ups were common.

Of all the MFM drive manufacturers at the time, there was one who was by far the definition of unreliable. Enter Kalok. Kalok was and is by far the definition of unreliable due to band slippage and high failure rates. Even after they left the industry in 1994, Kalok still holds that title as the most unreliable MFM hard drive and you'd be lucky if the thing ever worked at all. Let alone finding two that worked!

I'm glad you made a video showing how often they just can't be fixed. I've got one that doesn't work and I was trying to work out why I couldn't fix it as easy as some of the other videos that i had seen.

I had a similar model Micropolis HDD to that one and it was quite loud too. Seeing the motor PCB bought back memories. Compared to the original ball bearing based Seagate 3.5" 7200 RPM Barracuda hard disks the Micropolis was quiet. Those things were really loud. They were so loud that it was uncomfortable to be nearby. They ran roastingly hot too. It really makes you appreciate the later FBD designs.

One advantage in these old drives was that you could totally erase the platters, then low-level format them with speedstore and they would be back to normal operation. Modern HDD's have servo tracks and other lovely things written on the platters in the factory, that once lost the drive will never work again. Some software says it's low-level formatting them, but in reality, the drive just lies, it can only be low-levelled in the factory on a special jig. The head actuators are voice coil based, with their only reference being those factory servo tracks. once lost the drive has no idea where the heads are. One trick on modern drives is that outer tracks have more sectors than inner track, however the onboard controller translates all this into a nice linear pattern, so while the computer thinks the drive has so many tracks and heads etc, this has nothing to do with what is physically in the drive - in modern systems these days the whole concept of heads and cylinders etc has been abandoned, its all just a big long string of data blocks.

that water damaged seagate sounds like nightmares

Thanks for the fun MFM video! - Also, I love the half-smirk you got right while holding the screwdriver menacingly saying 'percussive maintenance!'

This video was not a bust—it was hilarious. Thanks for sacrificing all those cilia for us!

I had a ST-225 WAY back in the day. I'll note that those often get SUPER hot, which is part of what causes "sticktion". Even the best of them got hot enough to effectively melt and then boil away any lubricant used. I had one that after running for a day or two solid got hot enough to literally to unsolder it's own components. Seagate's answer to this was to always mount it with the metal body pressed against the cage to act as a massive heatsink. Always good to see older technology of yester-year. Also, most of the ST-225 were from the age where you could use MFM or RLL. Given then RLL would make the same drive about 38M (vs 23M), I'd bet the one you had was formatted as RLL.

I love your channel, Adrian, thanks so much for your hard work. I've opened up quite a few non-working old drives where stiction had been 'fixed', by force or by itself, to find the heads still stuck to the platters, ripped clean off their mounts. The noise it made when the drive was running was unmistakable. Happy days! 😂

They may have became unreliable today but when I used them in their days they never failed.