I've never seen a 486 motherboard with just three 72-pin SIMM slots. That is an oddity. This must be some proprietary design.

"ive never seen it, it must be proprietary"
dude, that is way out of the realm of reasonable. I have never seen jamaica, does that mean it doesn't exist?

That board is *PLAINLY* one of the smaller standardized AT form factors, and standard x86.

On topic, you really should put that voltage regulator back on the board, and if you want to also put a small to-220 heatsink on it.
I can't identify the board from a quick google, sorry.

jaqie wrote:

"ive never seen it, it must be proprietary"
dude, that is way out of the realm of reasonable. I have never seen jamaica, does that mean it doesn't exist?

Everyone here is entitled to their opinions on matters, provided that they are made with respectful intent. I've seen hundreds of 486 boards in my lifetime and have never seen one with only three SIMM slots and a QFP packaged Intel DX4-100. Have you? Considering the vast number of boards I have seen in the past, I'm guessing this particular board is some sort of non-consumer design board. Do you have a better explanation?

Comments like "dude, that is way out of the realm of reasonable. I have never seen jamaica, does that mean it doesn't exist? " are incredibly disrespectful and are not going to make you very popular around here. I see that you are new to the forum and have already noticed quite a bit of these impolite and sometimes “know-it-all” antics being presented by you. Please try to act a little more respectful towards others in your future correspondences.

The purpose of the forum is to share knowledge and theories of retro computer hardware and games with others. If you happen to disagree with someone’s idea, please do so in a professional manner and give sound argument for the disagreement. This will furnish further discussion by other members, and will hopefully unfold the truth of the issue being discussed. The next time you feel like bursting out with disrespect, please keep it to yourself, or re-write it in a respectful manner.

There are a lot of hits for a KM-S4-1, but it's quite different (socket, extra SIMM, etc)

http://motherboards.mbarron.net/models/486pci/km-s4-1.htm

This link shows a BIOS ID of 2A4IB000C-00, which seems to match your board. Perhaps the -1's CPU is socketed, and the -2 is soldered.

That board is *PLAINLY* one of the smaller standardized AT form factors, and standard x86.

What he meant by proprietary, is that it's not a board you could buy off the shelf in its day. As in, it was probably purpose-made for a brand name clone, like Acer, Gateway, Dell, and the like. Given that many of these boards have some quirk that stops you using them with off-the-shelf parts (like Dell with their non-standard power pinouts, or this specimen with the soldered-on CPU), I reckon feipoa is accurate in using the term proprietary.

on-topic: the VRM is back at its original position; I'll keep an eye on that corner to see how much it heats...

on-topic: there's at least another one (actually two, but I think they're identical) board I've found through TH99 with just three 72pin SIMMs (plus a few with 3*72pin+4*30pin) - http://stason.org/TULARC/pc/motherboards/M/MI … 86-MS-4145.html

on-topic: CPU is not Intel, but Texas Instruments

on-topic: unfortunately jumpers common to KM-S4-1 and KM-S4-2 don't match, and neither does the BIOS string (2A4IB000C vs. 2A4IBR22C)

off-topic: feipoa is right - if you disagree, even without arguments, you should do it non-disrespectfully; still, if you can't help it, at least be helpful with the subject of the thread...

iulianv wrote:

on-topic: unfortunately jumpers common to KM-S4-1 and KM-S4-2 don't match, and neither does the BIOS string (2A4IB000C vs. 2A4IBR22C)

Quite close though, I imagine the 000 is a placeholder, and "R22" is the BIOS revision or version.

But alas, if the jumpers don't match, that's not much use to you. Although the S4-1 has some "also known as" names that might yield some clues with a bit of Googling?

I agree that 3 SIMM slots is pretty weird. The only time I can honestly ever recall seeing this was on a hybrid 486-Pentium board based on OPTi or maybe some junk from PCchips. Obviously having a weird number of SIMM slots doesn't make the board crap since 486s generally don't require SIMMs to be installed in pairs unless there's some page-interleave going on.

I've seen a number of weird boards like this in China. One had a TI486-100 PGA chip soldered directly to the board, and another one with an ALD chipset and no cache. I think they must have come out quite late. So that plus being uncommon is going to make finding a manual borderline impossible.
I was really tempted to pick up a PCI 486 board with an ALD chipset. I've never heard of that one before, and supposedly it's not a relabeled (should be their own design).

http://item.taobao.com/item.htm?id=13338049628

I'm with feipoa on this one, this must be some custom mobo for a specific industrial/medicine/whatever use...

SquallStrife wrote:

What he meant by proprietary, is that it's not a board you could buy off the shelf in its day.

Aha. That's not what my knowledge of proprietary means - seems different definitions for same term got in the way here. As for others talking about respect and opinions - if he had posted it as an opinion and not as a fact, I would not have had an issue in the least with it - that was the very nature of the problem I had and why I posted what I did.

As I did have something on subject to add in my original post, but no longer do, I will leave the thread instead of derailing it further now that I have made myself clearer.

As for proprietary being 3x 72 pin simm sockets, I remember working on a board of such back when, but not much else about it, and it was standard in it worked normally and used normal parts for expansion.

Anonymous Coward wrote:

I've seen a number of weird boards like this in China... was really tempted to pick up a PCI 486 board with an ALD chipset. I've never heard of that one before, and supposedly it's not a relabeled (should be their own design).

http://item.taobao.com/item.htm?id=13338049628

Do you mean ALD or ALi? That photo shows an ALi board, which is clearly unique. It is PCI-based and yet does not have a ZIF. It contains 2 IDE ports, but not floppy/parallel/serial ports. I do not see any sort of voltage regulator, so I wonder if it uses just the 5V from the supply line and diode to regulate the CPU voltage (or not)? It has several components not soldered onto the board. I see what looks like the clock driver, but no bus transeiver or schmitt trigger. And where's the cache? Truely an interesting find, but I probably wouldn't buy it myself. I have a few experiences with ALi PCI 486 board and I ended up selling or tossing them. I think they are rather rare in general.

Hi everyone,
I know that this post is quiet old but does anyone have the above cited (02/28/96-SiS-496-497/A/B-2A4IBR22C-00) image BIOS file?
Thank in advance

Well, the board is tossed, but I kept the EPROM. I just "hot-saved" its contents on some socket7 board, using UNIFLASH - I'm attaching the file, hoping that is will be usable for you.