This one? Chipset, ISA/PCI slots, cache, RAM banks, CPU and ROM locations all matches your pic.

https://arvutimuuseum.ee/th99/m/A-B/33238.htm

This board has no serial or PS/2 ports either . The manufacturer decided to cheap-out on a super-io chip, but decided to provide cache sockets . Interesting design decisions for a board of that vintage .

Actually not all that interesting. It was quite common idea to not include IO and instead add another 8-bit/16-bit ISA slot.

The Serpent Rider wrote on 2020-06-13, 02:16:

Actually not all that interesting. It was quite common idea to not include IO and instead add another 8-bit/16-bit ISA slot.

On older machines this was quite common, but on a late-vintage 486, I am still surprised . The again, I have definitely not seen it all .

Is it possible this board was for some kind of embedded system?
It does seem odd to leave out all onboard interfaces *except* IDE.

jakethompson1 wrote on 2020-06-13, 02:41:

Is it possible this board was for some kind of embedded system?
It does seem odd to leave out all onboard interfaces *except* IDE.

IDE was integrated in the SIS 496/497 chipset, so there was no extra cost except the connectors and a few passive components .

Thanks a lot for the identification guys, I really appreciate your help!

darry wrote on 2020-06-13, 01:15:

This board has no serial or PS/2 ports either . The manufacturer decided to cheap-out on a super-io chip, but decided to provide cache sockets . Interesting design decisions for a board of that vintage .

I was really hoping that JP1 would be a PS/2 connector, but no, it turned out to be an external battery connector; otherwise I had really high hopes for this board.

There are some good things in this motherboard like PCI slots, up to 128Mb of memory support, small dimensions and support for different voltages like 3.45V, so I could finally test my TI processor. The downsides are lack of PS/2 connector, complicated jumper settings for CPU type that come in two rows continuously in various lengths from 2 to 5 (so need to draw that in an Excel spreadsheet before working with them - it's very easy to lose track where each jumper starts/ends) and 1.5 Gb hard disk limit. I also haven't seen 512Mb (or 256Mb for that matter) cache that would come in just 4(+1) chips.

Also, finding updated BIOS for this motherboard seems to be a futile endeavor.

ykot wrote on 2020-06-14, 00:05:

I was really hoping that JP1 would be a PS/2 connector, but no, it turned out to be an external battery connector; otherwise I had really high hopes for this board.

There are some good things in this motherboard like PCI slots, up to 128Mb of memory support, small dimensions and support for different voltages like 3.45V, so I could finally test my TI processor. The downsides are lack of PS/2 connector, complicated jumper settings for CPU type that come in two rows continuously in various lengths from 2 to 5 (so need to draw that in an Excel spreadsheet before working with them - it's very easy to lose track where each jumper starts/ends) and 1.5 Gb hard disk limit. I also haven't seen 512Mb (or 256Mb for that matter) cache that would come in just 4(+1) chips.

Also, finding updated BIOS for this motherboard seems to be a futile endeavor.

Jumpers not near as bad as some PcChips 486 boards. The BIOS HD limit is either 504Mb or 8Gb for that era (unless using an early modified BIOS translation scheme but that would be 4Gb limit, not 1.5Gb). DOS 6.x has a 2Gb limit, not sure where you got 1.5Gb but then do not know what you are using for an HD. For cache some boards did use 1Mbit dips and those that do have 512k cache typically can not cache any more ram than using 256k cache. Has to do with the TAG chip, it actually sets the max ram cached, not the actual cache size afaik. Just an observation: you bought an AT motherboard so you should expect it to need an AT keyboard.

Made by a company called Rectron, their "Terminator" board. I have surprisingly little info on this one right now.
Can you make a backup of the bios first and post it somewhere for download?

Into the Russian scans we go...

And we seem to have something that might match.

Can you please check and confirm this is right or not?

As for the bios disk limit, since it is Award it may be patched for disks up to 64GB or even 128-ish GB. We have tools for that, alas no 100% guarantee.

@evasive This isn't the right manual : in your manual the mobo has three ISA slots but this mobo has four. Most of the connectors/jumpers are matching or matching closely so this may be just a different revision ? who knows.

There are also com ports and a floppy disk connector in the manual you've found.

yeah, there is a very similar version of the same board with I/O controller:
https://arvutimuuseum.ee/th99/m/A-B/33161.htm

serial/parallel headers are were the 4th ISA slot would have been.

Horun wrote on 2020-06-14, 04:13:

DOS 6.x has a 2Gb limit, not sure where you got 1.5Gb but then do not know what you are using for an HD.

I've put a 8Gb HDD and BIOS detected it as ~1.5Gb. However, it does work correctly with my SD card adapter and a 1Gb SD card, so I assumed the limit was somewhere around 1.5Gb.

Horun wrote on 2020-06-14, 04:13:

Just an observation: you bought an AT motherboard so you should expect it to need an AT keyboard.

I meant PS/2 connector for mouse, some motherboards like my FIC 480-VIP-IO have such connector, so I thought this one would have it too, before knowing which motherboard it was. I actually got it in its own very nice looking compact AT case (w/LED panel) and a working AT power supply. After some cleaning and whitening it'll look gorgeous. 😀

evasive wrote on 2020-06-14, 07:42:

And we seem to have something that might match.

It is not exactly the same board, jumper numbers are different as well as some connectors, as Deksor said. However, CPU type jumpers seem to match overall configuration - initially they were configured just as in the manual for Cyrix processor, which I removed. I adjusted them according to images for Intel DX/DX2/DX4, but the motherboard still detects my TI DX2/80 as a Cyrix chip, maybe because it is using 3.45 voltage.

evasive wrote on 2020-06-14, 07:23:

Made by a company called Rectron, their "Terminator" board. I have surprisingly little info on this one right now.
Can you make a backup of the bios first and post it somewhere for download?

I have attached current working BIOS dump from this board. It seems to be using STM M27C1001 UV-erasable EPROM.

evasive wrote on 2020-06-14, 07:43:

As for the bios disk limit, since it is Award it may be patched for disks up to 64GB or even 128-ish GB. We have tools for that, alas no 100% guarantee.

Can you please elaborate more on this? I would definitely like to try it.

ykot wrote on 2020-06-14, 17:48:

I've put a 8Gb HDD and BIOS detected it as ~1.5Gb. However, it does work correctly with my SD card adapter and a 1Gb SD card, so I assumed the limit was somewhere around 1.5Gb.

I guess the BIOS has a 2 GiB limit (that is 2 * 2^30) bytes and takes capacity modulo 2GiB. A drive sold as "8 gigabytes" has 8GB (that is 8 * 10^9), which is around 7.45 GiB. 7.45 GiB modulo 2 GiB is 1.45 GiB, which is likely the cause for the capacity you observed.

There are 2 separate tools for doing this. I have tried both and both tell me this bios has no module available for patching i.e. this bios is too old to be patched with this method I am afraid.

evasive wrote on 2020-06-15, 14:05:

There are 2 separate tools for doing this. I have tried both and both tell me this bios has no module available for patching i.e. this bios is too old to be patched with this method I am afraid.

Could you please mention what tools are that? I would like to try something like this even if it's not specific to this board.