failuresuccess wrote on 2022-02-11, 04:56:

3.) The supported memory appears to be the 72pin type. Does the motherboard care if the memory is EDO or FPM?

Use FPM.
Only very late 486 boards support EDO.

7.) The onboard video card is a Cirrus Log CL-GD5424-800C-B and I believe it has 512KB of ram. I'd like to be able to play SimCity 2000 in SVGA on windows 3.11. Is 512KB enough or is more needed.

SimCity 2000 needs at least 640x480x8bpp, so 512 KB would be enough.
Though I believe you have 1024 KB - those two SOJ chips next to the CL-GD5424 seem to be 256Kx16 each.

failuresuccess wrote on 2022-02-11, 04:56:

Hello all, […]
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Hello all,

I got the bug to start working on my 90s and early 2000s hardware again. I dug out my IBM PS/1 Multimedia or more specifically what's left of it (motherboard/riser card). This was my first PC going back to my childhood so I've got a fair amount of sentimental value for it so I'm hoping to breathe some life back into it. I'd like to be able to setup a couple of CF cards, one running dos 6.22/windows 3.11, one running Windows 95, and another with a heavily customized Gentoo compiled for i486. I also want to max out its specs, something I could never do back in the 90s.

First I'd like to figure out exactly which motherboard I have but my googlefoo is weak. At the moment the best I've been able to find is at uncreative labs and the page appears to cover several submodels.
http://www.uncreativelabs.de/th99/m/I-L/34755.htm
My PS/1 Motherboard
ps1_motherboard_small.jpeg

These are the following items I'm currently working through to restore my PS/1. I'll update this as I find out on my own or from feedback in this thread.
1.) Does the motherboard support AT power supplies or is it IBM proprietary?
2.) Are there any horizontal desktop cases out there that the motherboard/riser card can be mounted into?
3.) The supported memory appears to be the 72pin type. Does the motherboard care if the memory is EDO or FPM?
4.) Can the motherboard support 64MB ram or is it limited to 32MB?
5.) The motherboard appears to have a jumper(J25) to enable/disable the add on cpu socket. Does this cause any issues with OverDrive cpus that use a pin to enable/disable this feature?
6.) Is it worth getting the Intel 83Mhz OverDrive cpu over the AMD 586 133Mhz?
I've yet to read the following discussion on the topic.
The Ultimate 486 Benchmark Comparison
7.) The onboard video card is a Cirrus Log CL-GD5424-800C-B and I believe it has 512KB of ram. I'd like to be able to play SimCity 2000 in SVGA on windows 3.11. Is 512KB enough or is more needed.

Any feedback is appreciated and I'll update this initial post with more details as they come!

1.) I dont see an AT power connector on the board, it does have what looks like a IBM only PSU connector, im guessing you will need a PS/1 PSU with the right IBM connector on it or a way to adapt a AT PSU for the IBM connector.

You might also want to consider washing that board, its looking a bit grubby and a quick wash will make it easier to spot damage components and traces, washing it under water wont hurt it just be gentle and use a paint brush to gently clean the dirt off it, then let it dry in a warm dry place for a few days. If you really want you can buy some Isopropyl Alcohol and give it a quick rinse with that to help remove the water.

failuresuccess wrote on 2022-02-11, 04:56:

First I'd like to figure out exactly which motherboard I have but my googlefoo is weak. At the moment the best I've been able to find is at uncreative labs and the page appears to cover several submodels.
http://www.uncreativelabs.de/th99/m/I-L/34755.htm
My PS/1 Motherboard

At this I will make the obligatory mention that there is a new project, run by some folk here including @Deksor, doing massive work to improve this database. The bad news is that for the moment, the page for your board doesn't have much more information:

https://www.ultimateretro.net/en/motherboards/2949

Here are some other PS/1 pages for reference:

https://www.ultimateretro.net/en/motherboards/10471
https://www.ultimateretro.net/en/motherboards/2948
https://www.ultimateretro.net/en/motherboards/2947

All going well you'll be able to get the warm fuzzy feeling of contributing the first photos for your board, and ideally even a BIOS dump.

This is also a good online resource to check thru - http://ps-2.kev009.com/pcpartnerinfo/ctstips/3ab6.htm - there's a lot of info on the site but it's not always logically connected, so you may have to search a bit up & down the page structure.

Your boards FRU # doesn't seem to be listed (maybe not surprising if its an original rather than replacement part) but like your find, the closest here is this page - http://ps-2.kev009.com/pcpartnerinfo/ctstips/a9ba.htm - on a quick trawl thru some other pages I'm thinking maybe a model 2133 (possibly sub-model 11,13, 14 or 46) as there seem to be boards that match yours - 25MHz rather 33MHz, 2 rather than 4 72 pin slots, zero cache / tag non-upgradeable & 512/1024Kb video memory - though there are so many differing configs within and across sales regions I could be well off the mark.

2.) Are there any horizontal desktop cases out there that the motherboard/riser card can be mounted into?
I doubt it as no standard existed on where to place the onboard ports, (Video, serial , etc) and imagine IBM tower cases used a different motherboard without the riser card.
Some people have done some serious case modding though and MADE it work.

4.) Can the motherboard support 64MB ram or is it limited to 32MB?
Good chance the motherboard wont be able to cache the full 64MB so you'll actually take a performance hit anyway going that high. (I still do it on my motherboards though, just because)

5.) The motherboard appears to have a jumper(J25) to enable/disable the add on cpu socket. Does this cause any issues with OverDrive cpus that use a pin to enable/disable this feature?
This would disable the onboard SX chip and turn it inot a "normal" motherboard with no CPU installed. so you can use that POD or whatever.

6.) Is it worth getting the Intel 83Mhz OverDrive cpu over the AMD 586 133Mhz?
Much the same, in real world usage. Doom see's hardly any benefit and Quake is no fun on a 486. POD is really useful on motherboard stuck at 5v though

Re: Another 486 being built
586 133, 3dBench2 FPS=61.2, PCPBench FPS=18.4, Doom FPS=33.11, Realticks=2019
POD 83, 3dBench2 FPS=60.8, PCPBench FPS=19.1, Doom FPS=37.95, Realticks=2314

Re: Osbone 486 DX2 66 VL-Bus (My 1st PC ever)
DX2 66, 3dBench2 FPS=43.4, PCPBench FPS=11.1, Doom FPS=26.41, Realticks=2828, Quake FPS=6.8
DX4 120, 3dBench2 FPS=52, PCPBench FPS=13.9, Doom FPS=30.64, Realticks=2437, Quake FPS=8.5
586 133, 3dBench2 FPS=52.4, PCPBench FPS=14.2, Doom FPS= 31.38, Realticks=2380, Quake FPS=8.8
POD 83, 3dBench2 FPS= 56.5, PCPBench FPS=16.4, Doom FPS=32.41, Realticks=2304, Quake FPS=12.2

Thanks, everyone for so much quick feedback!
I have my evening reading ahead of me 😀.

I re-found a tutorial I had followed to get Gentoo to compile for i486. I didn't realize he had the PSU go out on him but he was able to replace it. It's under the "FAULTY POWER SUPPLY UNIT (PSU)" section.
https://yeokhengmeng.com/2018/01/make-the-486-great-again/
His board looks similar to mine, he mentions that the PSU is an LPX type, I've never heard of that before. It looks like he found the appropriate adapter and a 12V psu to ATX converter. I'm not familiar with either but once I have a bit more I'll update the initial post.

TrashPanda wrote on 2022-02-11, 07:46:

You might also want to consider washing that board, its looking a bit grubby and a quick wash will make it easier to spot damage components and traces, washing it under water wont hurt it just be gentle and use a paint brush to gently clean the dirt off it, then let it dry in a warm dry place for a few days. If you really want you can buy some Isopropyl Alcohol and give it a quick rinse with that to help remove the water.

I'll give that a try, I know you can use rubbing alcohol but I didn't realize water wouldn't cause problems. I actually gave the board a quick rub down with alcohol before snapping the picture. The entire thing had some really nasty thick dust on it that wouldn't come off easily.

This look like it? https://eprm.ardent-tool.com/eprm/f296.htm (Main section https://eprm.ardent-tool.com/eprm/f4.htm )

edit: still looking, can't get any warmer than "Some kind of 21xx Aptiva-ish thing, probably" ... what's weird though is I'm not finding machines with GL5424 graphics listed, only 5422 and 5428.

Check out my IBM PS/1 restore posts.

1) IBM PS/1 Multimedia ( max restore ).

2) IBM PS/1 Consultant 1993 with Sound blaster.

Also see this Manual and search for your Model.
There where about 7 or more different models of the IBM PS/1
And they had slightly different motherboards.

So you will have to search this manual to find your motherboard but I am sure it’s in this manual.
Link: http://ps-2.kev009.com/pccbbs/aptiva/63g2028.pdf

failuresuccess wrote on 2022-02-11, 16:59:

I re-found a tutorial I had followed to get Gentoo to compile for i486. I didn't realize he had the PSU go out on him but he was able to replace it. It's under the "FAULTY POWER SUPPLY UNIT (PSU)" section.
https://yeokhengmeng.com/2018/01/make-the-486-great-again/

Haha Gentoo on a 486. That's a multi-week project. 😀
(disclaimer: Gentoo and its derivative Funtoo are the main operating systems I use. Typing this on my Funtoo laptop)

1/ seems psu is normal AT, just in a smaller form factor https://web.archive.org/web/20120707094723/ht … /formLPX-c.html
2/ you might need to get creative with a dremel
4/ I know everyone wants to cram as much ram as possible, but you will NEVER run (for more than 2 minute 'hey this loads, lets move on') anything needing more than 16MB on a 486. 12MB was the upper limit of usefulness, plenty of Pentium systems ran fine with 16MB ram for all of their lives.
6/ same speed except for one particular case - Quake, but Quake would be unplayable either way as you need Pentium ~120MHz for >20fps.
7/ 1MB VLB GD5424 but no cache on board, IBM sure liked being weird. Wonder if you could add cache, how many components are missing.

So I can't for the life of me find on ebay or amazon an atx to at adapter that supplies the -5v. Oddly enough I can find plenty of posts where people have been able to get them in the past. However, I did come across this nifty little board that takes the -12v from an isa slot and feeds it back in -5v on the -5v rail.
https://www.ebay.com/itm/174744918558?hash=it … -0AAOSwhaFhJPyB
I doubt I'll need to fill all 5 isa slots so giving up one seems like a possible solution.

As for the rest of the power supply needs I'm looking at this atx to at adapter.
https://www.amazon.com/7-Inch-20-Pin-Button-C … r/dp/B075ZPWJBX

This 12v to atx power board
https://www.amazon.com/Mini-Box-picoPSU-160-X … 0_t4_B071P3HMNK

And this 12v power supply
https://www.amazon.com/ALITOVE-100-240V-Conve … B07MXXXBV8&th=1

More to come!

That is a 2133 or 2155 motherboard.

1) Regular AT power
2) Look for LPX cases. It's a "loose" standard so not all are the same though.
3) You need 72-pin Parity FPM RAM with IBM presence detect. For example Kingston KTM0130 (8 MB), KTM0160 (16 MB), or KTM0320 (32 MB)

Something else to note is the hard drive size limit is 504MB. You will need a BIOS extension ROM or drive overlay for larger drives.

Updates!
So I've got the computer up and running with DOS 6.22, a 52X cd drive, and a non PNP AWE32. Doom 1 and Wolf 3D both work and seem to play ok but Doom 1 is a bit slow with settings maxed out even with 32MB of ram. So I'm guessing the bigger CPU I have coming in should help.
Now for the troubles.
At first I had no trouble using a 3.5" floppy drive, I was able to install DOS 6.22 and the whole AWE 32 floppy set. However, over the past few days the computers ability to use the floppy drive got more and more flaky. I went ahead and opened the drive up, lubed the two shafts with lithium grease and cleaned the heads with alcohol but no luck. I tried a second drive and performed the same maintenance just to be safe but no luck there. I've also tried several different ribbon cables.

When the computer powers on I can see the read/write head move but once I'm in DOS if I try to interact with the drive I get an immediate failure. Could this be a sign of the controller failing on on the motherboard?

The next issue I'm running into is when I use my CF card to ide board with a CDROM on the same ribbon cable. It doesn't seem to matter if I set the cf card reader to master and the cdrom to slave or use cable select. At worst the system won't boot into DOS, at best it will freeze up when using the OAK driver. On the other hand if I use a 20GB Maxtor drive I had laying around with the CDROM everything works just fine. Has anyone seen this strange interaction before?

Below are links to the cf to ide board and cfcard.
CF to IDE
https://www.amazon.com/dp/B0026OYEEQ?psc=1&re … product_details

CF Card
https://www.amazon.com/dp/B000W0BC7I?psc=1&re … product_details

Can you boot from a floppy?

Some CF cards don't like running master/slave with another device. If your sound card has an IDE channel, use that for your CD drive.

I'll see if I can encourage the floppy driver/controller to behave long enough to try today.

Well that doesn’t look good. I washed both sides last week and maybe I just missed it but does that look like corrosion near the floppy connector pins? I’m wondering if my growing floppy drive issue is because the solder joints are bad.

So one positive update, I found a 52x cdrom and it plays nice with the cf card. No idea why my other cd and dvd drives didn’t want to cooperate.

It looks like dust to me. Corrosion is usually green. But I would clean it anyway.