MFM Drives can be tricky to get up and running as quite a few of them require the actual controller board they were initially formatted with to function correctly, its possible to use an identical controller board if you know what one was used originally. They are also rather fragile both due to age and the delicate drive components, many also have sticktion due to the shitty rubber stops that got used at the time that turn to goo with age.

You can also take a chance and hook them up to a board you have already and see if it can read them.

Adrian over at Adrian's Digital Basement has a few videos on the subject of restoring MFM drives, I would have a watch as he goes through the trouble of trying to get a few working. (Not always successfully)
https://www.youtube.com/watch?v=8LbFKV_pPAE
https://www.youtube.com/watch?v=koei2ROGtiQ
https://www.youtube.com/watch?v=CpQ2j2J6wL0
I can happily recommend his channels to anyone interested in old retro stuff and restoring it.

https://www.youtube.com/@adriansdigitalbasement/videos - Main channel
https://www.youtube.com/@adriansdigitalbasement2/videos - Second channel full of retro bits

just spin them up, if they don't take off on their own you can manually turn the spindle motor (sometimes this requires removing the logic board)

2,3 & 6

in stead of banging on them with a screwdriver, you could also just hold them with the side where the heads are located a few inches above a sturdy table
and then bring it quickly down in a sudden motion onto the table.
Though that's mostly for when you know the heads are stuck. (2) should make that clear if they are or not.

I think there's another option involving a freezer but meh.. good luck. 😀

ST-250R is RLL, rather than MFM.
You can use it as MFM (with reduced capacity), but if you want to recover the data, an RLL controller is necessary.

Grzyb wrote on 2023-07-26, 19:07:

ST-250R is RLL, rather than MFM.
You can use it as MFM (with reduced capacity), but if you want to recover the data, an RLL controller is necessary.

Thank you my friend ! That is something I actually overlooked
So in case this drive spins well I will go on a hunt for a controller 😀

Cheers

weedeewee wrote on 2023-07-26, 17:14:

2,3 & 6 […]
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2,3 & 6

in stead of banging on them with a screwdriver, you could also just hold them with the side where the heads are located a few inches above a sturdy table
and then bring it quickly down in a sudden motion onto the table.
Though that's mostly for when you know the heads are stuck. (2) should make that clear if they are or not.

I think there's another option involving a freezer but meh.. good luck. 😀

UPDATE:
Well the results are in

I went with the options 2,3 and 6 as weedeewee suggested and were the least "invasive" and traumatic to the drive and.... IT WORKS ! ! !
The little bugger started right up ! No stichen

Only connected to a power supply
It spun up to speed and performed a very short seek noise .. just two short noises of the heads moving ... not that tak tak tak tak tak tak that you hear on other drives
I dont know how is the normal initialization noise for this drive as there is absolutely no video of it on youtube
The drive LED never lighted up
The ST-251 makes a long seek

Well at least it started and seem to make healthy MFM noises, no itchy or scratchy noises so now I will try to hunt for a MFM/RLL controller and hopefully be able to LL Format it tell the world there is another MFM (RLL) Hard Drive out there 😀

The other drive as I am afraid power cycling with unparked heads will not contribute to its health I will wait until I have the controller and software to test.

Thank you for the kind replies ! Here are some photos of the bugger 😀

I have Microscience and before connecting it to the power supply I checked it for short circuits on the 12V and 5V pin to GND and then after turning it on I saw black smoke and that's all so I took it apart and on PCB I don't see anything burnt. The motor runs without problems (moved by finger) but I think that it may be burnt (because, as I wrote earlier, I don't see any burnt components on PCB).

The seek noise during initialization isn't indicative of at least "some" health on these step-motor actuated drives. You won't find them to produce the infamous tak-tak-tak sound if the data cannot be read since they have "hard" cylinders. Only drives with a voice coil actuator, and among them essentially those with embedded servo, will make this noise if a head/platter surface defect is present.

My approach to preliminarily identify faulty, really ancient MFM / RLL / ESDI drives, without setting up a complete system, was to supply power, and wait for them to spin up in a noise-free environment. Then, I powered them down and held my ear very close to the cover of the mechanism. If it's possible to hear some very faint tick-tick-tick noise during the last revolutions before the spindle comes to a stop, a surface defect of the platters is very likely. On these ancient drives, the R/W heads are so heavy that it's actually possible to hear them "stumble" across the "craters" in the platter surface 😉

Once you've encountered a drive with such a damage, you'll know how it sounds and it's simple to identify a mechanically damaged drive.

I wouldn't recommend to dump the drive on its edge onto a table to "unstick" the heads. I always used to free them up by holding the drive by its edges in one hand and quickly accelerate (turn) it around the spindle axis. Rotary inertia will apply a much higher torque to the platter stack than the spindle motor ever could, while not exerting any kind of shock to the head assembly. If this won't lead to success, you can still "shock" the drive, but chances are high that it will be permanently damaged.

UPDATE guys:

So The ST-250R is alive and kicking! wwooooohoooo !
As I said when turned on it made a healthy spinup and then two very short seek sounds (not that tak tak tak tak tak tak that I see on YouTube videos)
Turns out this is because the heads were not parked... The ST-250R is NOT an auto park drive as I thought !!!!!
So at startup the heads were already at cylinder (track) zero and it didn't have to come tak tak taking from the parking area the last cylinders near the center... mystery solved.

I managed to get a Seagate ST-11R controller card and after several fiddling with different cables and many frustrating "no drive present" episodes I installed a cable with 3 leads similar to the 5 1/4 floppy and finally
it was recognized by the ST-11R

Now there is a mystery because the controller only initialized in ST-11 mode (MFM) and I could only see a table of MFM hard drives
I have no idea why it isn't displaying the RLL drives in the table as the ST-250R is RLL
Both ROMs are present on the ST-11R one for the 11 and another for the 11R... I will have to dig further

So I low level formatted it as a ST-225 with 21 MB haha and it churred along happily never complaining and formatted complete
Then I used FDisk to partition it and DOS Format to witch it complied splendidly... no bad sectors nothing

Hurray ! another MFM lives on !

Next I plan to spinrite it to ascertain how the disk surface is (it does have a defect table written on it) and to determine the optimum interleave

Finally I want to see how I can properly format it as a RLL 43MB that it is

I'll post the progress here

Cheers!
Nuno

Older versions of ontrack disk manager have a low-level formatter.

I would advise using the bios routine in the controller card using debug though.

If the controller is an rll controller, the routine in the card should do it as rll.

wierd_w wrote on 2023-09-02, 06:13:

Older versions of ontrack disk manager have a low-level formatter.

I would advise using the bios routine in the controller card using debug though.

If the controller is an rll controller, the routine in the card should do it as rll.

Yes I used the debug command and run the controller bios program and it only shows options for MFM drives, not RLL
Today or tomorrow I will swap the ROMS on the ST-11R controller card to see if that helps
One ROM is marked ST-11 and the other is ST-11R

I'll post the results

wierd_w wrote on 2023-09-02, 06:13:

Older versions of ontrack disk manager have a low-level formatter.

I would advise using the bios routine in the controller card using debug though.

If the controller is an rll controller, the routine in the card should do it as rll.

Ok last post in this series to anyone that may be interested to know

- Seagate ST 250R
I got the wrong controller a ST11M - there seem to be 2 very similar controllers, one is just for MFM (ST11M) and another support a handful of RLL drives inclining mine (ST11R)
I now got the proper controller and it formatted the drive in RLL mode to a whooping 42mb I only heard a minor hiccup during formatting but no bad sectors have been shown .. so DOS formated the disk without incident

- Microscience HH-725
This is a simple MFM type 2 drive with 20mb
Initially there was no activity and the 12v line was open ... after following the traces I came across a blown tantalum capacitor staring me in the face ... how didn't I notice that before
In the end there were 2 bad tantalums and after I replace them (along with 2 other just for good measure) the disk spun up perfectly - I did started it on a dorsal position to minimize some possible head damage in case of something stuck or vibrating with the first start...
I also applied a drop of machine oil on the stepper motor
The disk formatted fine with an MFM controller in SpeedSTOR and reported a handful of bad sectors ... but in all it works fine

Thank you all that helped