As far as I know there is not a drop in replacement. There were a couple of different sized drives IIRC. You will probably want to check Louis Ohlands 9595 pages for details. Your options are SCSI really. You may get the controller for standard MFM or ESDI drives in there, but then you may as well go SCSI. Either way you loose a slot. Do you need the three slots for something else? Most i can think of putting in the system is NIC (token ring, of course) + Video + SCSI.

Usually configuration if you are needing more than 512K (older 50 with dumb 2 slot 30pin) or 1MB or 2MB ram (50Z with one 72pin slot) (depending on motherboard) is using 16 bit memory expansion board (MCA) to add 4MB more.
So that leaves 1 slot for networking. If using a video card which is pointless, you wouldn't want to do using 1024x768 which is interlaced 48hz which is horrible to look at so save your eye balls. 😀

Cheers,

I forgot about the RAM upgrade. The 8514/A isn't too bad with the right kinda monitor. Probably overkill anyway in a model 50.

I’d need SCSI, memory plus NIC. Are there any new/available MCA memory boards?

Ebay. Plenty of these.

Cheers,

romtos wrote on 2020-08-30, 20:40:

I’d need SCSI, memory plus NIC. Are there any new/available MCA memory boards?

(for the price of two complete PS/2 model 50s)

No. PS/2 series are expensive these days, even parts are as well. That something you have to live with.

Cheers,

The special snowflake IBM drives from that era were extremely reliable.... Reliable to fail.

I've often toyed with the idea of making an adapter to put an SD card in its place, but since IBM made a different drive for each and every machine (or so it feels like), the work / reward, just isn't there for most people.

Also, why do you need a memory board? on a 286 it's rare to really "need" more than 1MB.

luckybob wrote on 2020-08-31, 18:47:

Also, why do you need a memory board? on a 286 it's rare to really "need" more than 1MB.

Would like to run OS/2 1.3 on it. This requires more than 1 MB; better 4-5 MB.

pentiumspeed wrote on 2020-08-30, 22:32:

Ebay. Plenty of these.

As always, I seem to be living in the wrong part of the world …

romtos wrote on 2020-08-31, 21:18:

Would like to run OS/2 1.3 on it. This requires more than 1 MB; better 4-5 MB.

I installed 1.3 on a model 80 and it was quite slow. IIRC 4MB RAM. It also had some fast ESDI drives on it.

romtos wrote on 2020-08-30, 18:31:

is there a “drop-in” replacement for the ST-506 hard disk of a PS/2 8550 (80286)?

There is. Seriously, just stumbled upon this thread and thought I'd share my thoughts on this. First off, being among the very first PS/2 models IBM announced Model 50 definitely deserves some love. Even if I prefer SCSI (or XTIDE) in pretty much every other PS/2 (or early PS/1) computer, with Model 50 you preferably wish to utilize that "hidden" 4th slot (where the original HDD card was sitting). For this, I am using an ARCO IDE (MCA) adapter:

It got its own bios and allows me to boot right off from the connected IDE device thus, replacing an original hard disk. Better yet, it has its own Molex 4-pin power output connector so fitting, say, a DOM or similar is a breeze - works wonderfully. The only caveat I've read about is, that this adapter is using a non-standard IDE address, which might give some headcache with Windows 95 and above (so not really a con when put in Model 50 imo). This rewards you with all three slots available for something else.

As others have said, if your're sticking with the 286 processor, I wouldn't bother with the memory expansion either. I recently upgraded mine with the IBM 486 upgrade kit so going forward with the 1MB onboard memory just didn't feel right. Other than that, I've also been experimenting with Gotek on this one - works brilliantly when flashed to the latest FlashFloppy firmware after initial troubles with Gotek standard firmware.

I want a MPU-IMC card.

*pouts like a child*