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Last month I did a article on the IBM Model 55sx, A machine I myself was not to crazy about. It was certainly functional but hampered by so many little things and a few big things as well such as the proprietary MCA expansion ports. This time I’m going to talk about the Model 30 286 also of the IBM PS/2 line. This machine seems to have become one of the more desirable PS/2’s most likely because this machine unlike many others of the line is actually equipped with standard 16 bit ISA slots. will this be enough to redeem the system or will it be dragged down by the little issues that plagued the 55sx? Lets read on and find out.


The case is virtually identical to the previous 55sx and again it’s a nice small desktop case. Again there is not much room for expansion and your basically limited to a standard floppy drive, hard drive combo or two floppy drives.

ps2302863Taking a look at the back.


Not a whole lot to say since the back is very much like the 55sx though arranged a little different. The VGA port is mid case and before the other ports. The port is indeed VGA and not MCGA as on the 8086 based model 30. The port on my machine did not work but I’m unsure of the reason. perhaps a dead video chip. Below and to the right are two ps/2 ports for keyboard and mouse. Following that is a larger serial port and a parallel port.

I won’t go over the two cards I installed but they are a Trident 8900 VGA card and a early 16-bit Sound Blaster 16 sound card. The sound card is a bit “noisy” but its setup by jumpers which is important seeing as this is a 286 based machine and the plug and play setup program requires a 386.

The floppy drive is a 1.44mb drive but like most of the ps/2 line it is proprietary so you need a floppy drive just for the ps/2. also like the 55sx it uses a sled that the drive sits on to install into the bay.


The hard drive is also the same ESDI style drive that was in the 55sx with the same style connector. Mine is what appears to be the original 20mb drive and it still boots up just fine.


The first thing you can tell right off on opening the case is that the model 30 286 is one of the few ps/2 models that use the 16 bit ISA expansion slots as opposed to MCA. This was because at the time this was considered the cheaper budget version but as time saw the MCA format die off this model and its slower 16 ISA has remained far more versatile and useful as a retro computer.

1) Power supply & switch – This machine again uses the common power arrangement found in the IBM PS/2 line of having a mechanical switch connected to the front that via a hooked rod physically powers on the PSU on power up. A little strange overall but from researching and comments this actually turns out to be a safer method then directly connecting the power to a front switch as is the common practice.

2) CPU – The Model 30 286 as the name would imply uses a 10mhz 286 CPU. The 10mhz 286 is one of the earlier and slower 286 CPUs and in my opinion for this machine is in a rather awkward place. I say that because it feels a little to fast for some CGA games that require a 4.77 8088 or V20 to play at correct speeds. At the same time the 286/10 is a bit to under powered for the bulk of the later VGA games and lacks the “coolness” factor of a NEC v30 machine that’s for the most part running at the same speed. It should run many slower paced games from the late 80’s and maybe even early 90’s in EGA fine though.

ps2302868I’m not sure the reason for that yellow wiring above the CPU chip or if that’s factory done.

This CPU crystal oscillator is soldered onto the board.  You could in theory desolder everything and resolder on a faster oscillator and add a faster chip but it’s unknown if this will work or be stable. There are A few official CPU upgrade “snap” on upgrades though such as the HyperACE SX (M30) as well as a few others do exist. I’m not sure though if these upgrade chips will work with other machines or if they are specific to the model 30 286.

486slc2486SLC2 50mhz 486 cpu upgrade (image courtesy of user Nestor at at the forums)

IMG_20140407_114755_540 HyperACE SX (M30) 386-25mhz CPU upgrade w/ math copro / 64k SRAM cache (image courtesy of user lowen at the forums)

3) co-pro socket – This is a socket for a 287 math coprocessor to assist with complex mathematical computation. Mine as you can see lies empty. Not terribly useful unless your doing CAD applications or running one of the few games like SimCity that take advantage.

4) CMOS Battery – Again we have the infamous Dallas RTC battery. Mine seems to be the later revision but unfortunately it still appears to be either incompatible or dead. I’ll repeat here what I wrote in my model 55sx article “The Dallas RTC is basically a lithium battery coated in a hard plastic shell and then socketed into the board. The problem is these chips and even their updated and more recently manufactured replacements are out of production. Throw in the fact that many of these are now dead, the newer replacements aren’t guaranteed to work the same and that the system will act erratically, throw errors (error 161) on boot or not work at all without a working battery and you have a major issue. The best fix for this issue is hacking the battery to use a modern coin form lithium battery externally. Instructions on this process can be found here as I have not attempted it yet. Ive read and seen some videos where the newer replacement battery the Dallas DS12887 works fine but other sources indicate issues such as a clearing of the CMOS after restarting.”

It is worth saying that my machine seems to be able to boot up to its hard drive regardless of the CMOS battery being dead and without the need for a reference disk. After the error codes if you wait a few seconds an image will appear and if you hold down the F1 key the machine will continue to boot up.

5) Speaker – The speaker on the 30/286 is a cheaper Piezo beeper speaker which makes sense seeing as this was considered a budget machine.

6) RAM – My machine has 1MB of RAM installed but the max capable is 4MB. unfortunately the PS/2 30/286 does not take standard 30 pin RAM but instead uses proprietary “PS/2 Type” RAM which can be a little hard to find. Some of the IBM RAM sticks use sort of odd looking metallic box memory chips as you can kind of see in the image below.


So is the PS/2 model 30 286 a good retro machine? Well…not really, at least compared to other OEM or self built setups. Again in my opinion it’s from the hassle involved. The proprietary RAM, the proprietary floppy/hard drive interface and Dallas RTC battery and even still the reference disk even if its not as big of a deal. Is it far better as a retro PC then the “high end” MCA PS/2s? Yes, and if you are a IBM fan and want a PS/2 then I would suggest this machine. Many of the above issues of the other models are mitigated by the use of standard 16 bit ISA slots in this machine. The hard drive can theoretically be replaced with something larger and newer via a cheap and available ISA IDE or SCSI controller. The problem with doing this is that there are NO molex power connectors on the PSU to power a hard drive or floppy drive. I am unsure if a standard power supply will fit in its place but even if it did it was almost assuredly make the front power switch useless. Upgrading the sound and video is also much easier with the huge array of ISA video and sound cards now usable. Earlier sound cards that are jumper configurable are recommended though due to the none plug and play nature of the system. As I mentioned earlier the CPU for me holds kind of an odd place but if you don’t have any other better machines of the era this one should fill some of your needs.

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  1. Can the onboard graphics be disabled?

    • The onboard graphics are automatically disabled when the machine boots and detects a VGA card installed in one of the ISA slots.

        • Dinis
        • Posted September 5, 2015 at 02:08
        • Permalink

        I wonder if the the latter PS/1 could do that.

  2. I have one of these PS/2 286 Model 30s that has been upgraded with a Kingston adapter card to a 386sx. I didn’t realize I still had this. I have an 8bit harddrive adapter card installed in it and have gotten it to recognize a larger harddrive, but it is still only set up to 40 MB on a harddrive that is 120 MB. All this was done so long ago, I don’t remember doing it. Most of the files are dated 1992 or earlier. I am currently looking at changing out the floppy drive for a floppy drive emulator, but PS/2 floppy drives have a different pin out than the standard 3.5 floppies, so I am going to have to build an adapter. The PS/2 drives have power in the 34 pin ribbon cable as well as a few other signal changes. Not too different, but just enough to get into trouble.

  3. Hello Sir,
    I got one of this from my boss: it stayed in the attic of his office for some 20 yrs, he was about to throw it away but I stepped in and convinced him to dump it to me 😛
    I know nothing about hardware, and consider that my age is exactly the one of this model, which makes it for me completely stranger.
    Turned it on…checks the RAM…ok…then “non system disk or disk error”.
    What does it mean? Was it perhaps formatted before forgetting it? Or has the HD failed?
    How can I solve this, any idea?

    Thank you for this page, it was very helpful to put it back together and set it up. Just help me to overcome this setback please!!!

    • oh, the reference disk. This is a common issue. The IBM PS/2’s require a start or “reference” disk to be setup. basically you need a floppy with the program for the specific model on it which you need to boot from. It will ask you a number of questions and it’s kind of like setting things up from a BIOS. After your done it should save the settings (provided the battery is good) and your good to go.

      try downloading the file on this website and writing it to a floppy and running it on the PS/2.

      I guess you’ll need a floppy disk as well as a computer with a 3 1/2 drive. My friend recently bought a PS/2 and hit the same problem, luckily I had the disk handy for that specific model and it works just fine.

        • Mark Neville
        • Posted February 26, 2019 at 22:27
        • Permalink

        I put in a different HD in the Model 30 286 to see what issues came up. I tried installing several versions of DOS and managed to do something that will take some time to recover from. I tried installing IBM PC DOS 5 and it complained that I didn’t have a version of DOS 2, 3, 4 or 5 installed. Apparently it was an upgrade set of floppies so that didn’t work. I tried Installing DR DOS 6.0. I think I messed up the disk in some way because when I tried to boot from the HD after the install, it got hung on a screen that said GNU GRUB. Reading about that it appears to be something used for booting multiple operating systems. It didn’t respond to the keyboard, so I couldn’t get anyware. If I booted from the install disk in drive a:, I could access drive c:. I feel that it is likely that I messed up the Master Boot Record with my choices. I will look further into my inventory of operating systems and see if I can find something that will install on this disk. I tried to put two disks connected to the computer, but FDISK /status seemed to only able to find C:.

        Sent from my iPad


    • I believe that means that the disk is not formated as a system disk. You need a DOS diskette to do that. I would first try booting from a floppy disk that has DOS on it. Then see if you can access drive C:. If you are able to do that then you can look around on drive C: so you know what is there. If not, I seem to recall there is a command chkdsk which would see if the disk is OK. If looks for bad sectors and marks them them as such so they won’t be used. If the idsk is functional, but has nothing useful on it, then you should be able to format the disk using the command format C: /s. That should makeput the basic DOS system on the hard disk. If you have a set of DOS install disks, it might be better to use them and get all the DOS commands. My model 30-286 has a lot of upgrades to it. I have the 286 replaced with a 386sx processor and I have an 8bit ISA board plugged in that lets it use larger harddrives. I am contimplating replacing that one with a 16 bit card that also has a floppy connector on it which would allow me to use floppy drives with standard pinouts, not being restricted to lusing the IBM ones. The IBM ones have power pins in the ribbon connector instead of a separate 4 pin power cable. I am impressed that these old computers still work. The silk screen on my motherboard says 1088. That means the design of the is more than 30 years old. If you need help with any DOS commands, try entering the command with a /h or -h after it. That shouldn’t execute the command, it should just give you the syntax and options for the command. So typing chkdsk /h should give you suggestions like ones to fix the disk, not just tell you it has issues. I have a set of IBM PC DOS 7.0 I used to install DOS on my machine. I would recomend something older. The version of Basic on that one wouldn’t display corrctly on my machine.

  4. I forgot about the refernce disk. I had one of those and now I remember using it. The other issue I had troubles with was the real time Dallas clock module. Those things were only specified to last 10 years, so after all this time they are likely to be dead due to the battery being discharged. I tackled this by two methods. One involved installing an external cutting into the plastic case of the module until I could make connections to the internal battery and installing an external one. Which worked, but wouldn’t recomend it for the faint of heart. The other way I attacked that problem was to replace it with a newer compatable Dallas module that has a slightly larger memory.

    • It’s been a while since I properly messed with a PS/2. You may be right about the HDD just not being formatted rather then it wanting the refrence disk. If I recall when my friend had the issue he got a diffrent error then “non system disk” and I think it directly asked for a refrence disk. Or maybe its not seeing the HDD because it hasn’t been set up with the refrence disk.

        • Mark
        • Posted February 24, 2019 at 23:29
        • Permalink

        I am the origal owner of my PS/2 Model 30-286, so I still had the floppy disks that came with it and I recall now that I used it. While this link is most about other things, if you scrowl back far enough through my other geeky stuff, yoiu will find phtos of my Dallas Real time clock fixes. I seem to remember that without that, there was some configuration work required each time you jpowered the machine up. At a minimum the clock needed to be set.

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