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What is that case with the AT PSU at the bottom? Anyone seen it before?

It's 386DX motherboard with CPU upgraded to 486DLC. Very nice setup if you ask me 😁

For HDD just use CF2IDE adapter and some small CF card.

This might be the board: https://stason.org/TULARC/pc/motherboards/S/S … 86-386-AD3.html

I have a bottom mounted AT PSU in my AT P133 PC.

I also thought it was very unique at first, but it seems some chassis at the time were built modular enough to be fitted either way depending on the faceplate and interior arrangement.

The case is what I always refer to as an 'upside-down' design, they were popular for a few years right at the beginning of the 1990s. It's pretty much a regular AT minitower, but with the feet on the side that would otherwise be the top. Can't say I ever found them any more or less infuriating than regular AT minitowers - always cramped & nasty to work in.

Btw, those SIMMs are almost certainly 1MB (Byte), not 1Mb (bit) each; 1Mb = 128kB and not a 'logical' size - single-sided SIMMs (both 30p and 72p) tend to be available in multiples of four, so 16MB, 4MB, 1MB and 256kB. Never seen them, but 64kB would be the logical next smallest size, not 128kB/1Mb. Watch the capitalization when it comes to memory or you get lost very quickly (particularly as chip density is expressed in bits and module size in Bytes).

VGA Card – Oak Technology - Model Unknown?

Model generally not very relevant. This is an ancient OTI-037 design, which is nice and compatible, but glacially slow, making even a Trident TVGA8900B seem zippy by comparison.

Multi IO CA8392-F - who made these?

Your photograph of the front has an FCC ID on it, IATCA8392. You can search on the FCC site and find it was made by Co Time Computer Ltd. That must help a lot 😜

What does help, is googling on the FCC product code (everything after the IAT grantee code), as that gives you this link with jumper settings:
https://stason.org/TULARC/pc/hard-disk-floppy … ves-CA8391.html

Unless you want to disable specific functionality you generally don't need to set too much, you just enable/disable the various interfaces with the jumpers and the motherboard BIOS handles the rest, just set drives & interfaces as if they were onboard.

Kingston KNE-2121H LAN 10 Mbit?

Yep, 10MbE with a nice AMD chip. When it comes to ISA stuff, 3Com's Etherlink III is unsurpassed for both driver support in any OS on earth and very good performance, but close on its heels in both fields are chips from Intel, AMD and Digital. They perform significantly better (and with lower CPU use!) than generic NE2000 (NS8390)/WD8013 chips within the limitations of an ISA platform. Note that AMD Lance chips (like this one) can be a bit touchy when it comes to resources (DMA!)

I love a good origin story.

Based on the BIOS ID string, your motherboard was manufactured by Seritech.
Seems like another user here on Vogons has the same motherboard (80386 BIOS image collection) but, you will notice that the 386DX-40 chip is soldered onto that motherboard. Yours has the PGA socket.
I agree with AlaricD that he has correctly identified your motherboard (here's another link to a site I normally use: http://arvutimuuseum.ee/th99/m/S-T/32373.htm).

Although your interest might be in Windows 95/98 games, I would hang onto this PC. You never know when your interests might shift one day to older games and PC technology. I also used to be just interested in the 386 to Pentium 1 era but, over the past 2 years, I became quite interested in XT PC's as well and have built up quite a collection.

When you disable the L1 cache on the 486DLC CPU (there are utilities available - refer https://www.philscomputerlab.com/cyrix-486dlc.html) then you basically have a 386DX-40 and, with the turbo switch off and/or disabling the L2 cache on the motherboard, you can slow down this PC to 286 speeds. Great for playing some of those older classics. I would perhaps try and source a nice 16-bit Sound Blaster Pro compatible sound card.

I would also hang onto that 16-bit NIC (LAN card). It has a Boot ROM socket and, with a flashed image of the XT-IDE BIOS on an EEPROM chip, you can actually boot up with the NIC and use much larger capacity hard drives and/or compact flash cards. You will most likely find that the BIOS has a 528 MB (504 MiB) size limitation.

I would also desolder that battery before it starts to leak all over the motherboard. Consider yourself fortunate that it hasn't leaked yet. It does have an external battery header that you can use.

Thank you very much guys for all the info and the comments. I am primarily interested in Win 95/98 gaming rigs at the moment and have a couple of projects on the go. However I can appreciate the advice here and it's starting to sound like I found a bit of a gem here - It would be stupid to ignore good advice so for now I will keep it. Damn I should have had the monitor and printer as well 😵

I have other hardware I am selling to help fund completing the other rigs and it's not like i need to sell this right now.

TBH It was only by pure chance and a sharp eye that this didn't end up in the trash today.

Actually I'm quite interested in getting it fired up and running, gotta find an AT keyboard or at least a PS2 -AT adapter. I did notice that one of the chips on the mobo says it is the keyboard controller. Would that only work properly with a Spanish keyboard layout or was the key map set by software even in the early 90s?

The Hard Drive I didn't get was a Caviar 850MB I'm sure. Oh and yes I meant 1MByte Simms not 1 Mbit.

I could do with getting some floppy disks to test the drives but even disks seem to be a bit pricey these days. I guess this would run DOS 6.22 and Windows 3.1? How would I load DOS? I remember when USB first came out and we called it 'Useless Serial Bus' but it feels weird not to have it on a PC now!

Hmm looks like I'm the proud owner of a 486. This is from around 1992/3?

That's a great find and a good platform to start with.

jesolo wrote:

When you disable the L1 cache on the 486DLC CPU (there are utilities available - refer https://www.philscomputerlab.com/cyrix-486dlc.html) then you basically have a 386DX-40 and, with the turbo switch off and/or disabling the L2 cache on the motherboard, you can slow down this PC to 286 speeds. Great for playing some of those older classics.

So the Texas 486DLC is a Cyrix 486DLC?

Rich

dicky96 wrote:

So the Texas 486DLC is a Cyrix 486DLC?

Yes.

The TI 486SXL is also largely the same except it has an 8KB, 2-way set-associative cache.

AlaricD wrote:

dicky96 wrote:

So the Texas 486DLC is a Cyrix 486DLC?

Yes.

The TI 486SXL is also largely the same except it has an 8KB, 2-way set-associative cache.

I think this article provides for some good background info: https://en.wikipedia.org/wiki/Cyrix_Cx486DLC

dicky96 wrote:

I could do with getting some floppy disks to test the drives but even disks seem to be a bit pricey these days. I guess this would run DOS 6.22 and Windows 3.1? How would I load DOS? I remember when USB first came out and we called it 'Useless Serial Bus' but it feels weird not to have it on a PC now!

I'm sure there are fellow collectors in the UK that are willing part with a couple of floppy disks (both 1.44 MB & 1.2 MB). However, on a 386/486 based PC like this, you don't really need 1.2 MB disks anymore but, keep the drive anyway.
Once you've managed to find a suitable replacement for a hard drive (either another one or, a CF or SD card with the appropriate adapter), you will then have to try and obtain a bootable floppy disk to boot DOS 6.22 (you can also go the GoTek floppy drive route - refer: https://www.philscomputerlab.com/gotek-floppy-emulator.html & https://www.youtube.com/watch?v=GmtNeYpbGzI)
Once you've booted DOS 6.22, then it's merely a matter of running FDISK, partitioning & formatting your hard drive. Just take note of the FAT16 partition size limitations (2.1 GB) and that your BIOS might also have a hard drive size limitation (which you can overcome with the XT-IDE BIOS on your NIC).

dicky96 wrote:

Hmm looks like I'm the proud owner of a 486. This is from around 1992/3?

More like late 1993 (based on your BIOS date).

dicky96 wrote:

... This is from around 1992/3?

Seems like it's all over the place, really. The motherboard and CPU/FPU carry 1994 date codes, the I/O and VGA cards look to be from 1991, the NIC appears to have been made in 1993, and the AC2850 HDD you didn't receive was available around 1995~1996. I can imagine the machine started as a 286 or something and was slowly upgraded piecemeal over the following few years.

dicky96 wrote:

Thank you very much guys for all the info and the comments. I am primarily interested in Win 95/98 gaming rigs at the moment and have a couple of projects on the go. However I can appreciate the advice here and it's starting to sound like I found a bit of a gem here - It would be stupid to ignore good advice so for now I will keep it. Damn I should have had the monitor and printer as well 😵

Whatever you do, don't go running Win95 on here. It will technically work, but be about as enjoyable as watching paint dry 😉

It's not a unicorn you have there, but definitely a little gem, at least the motherboard (and the NICs not bad either). I'd agree with jesolo about the sound card. I'd also recommend a different VGA card (just about any different VGA card...). As for HDD, the 850MB tells us that the BIOS can handle up to 2GB, which is unusual with 386 boards like this. Of course XT-IDE can help, but native flexibility is always good.

Actually I'm quite interested in getting it fired up and running, gotta find an AT keyboard or at least a PS2 -AT adapter. I did notice that one of the chips on the mobo says it is the keyboard controller. Would that only work properly with a Spanish keyboard layout or was the key map set by software even in the early 90s?

90% software (and 10% VGA BIOS for the fonts if you want odd characters). Run default DOS without any keyboard drivers and it will default to US.

I could do with getting some floppy disks to test the drives but even disks seem to be a bit pricey these days. I guess this would run DOS 6.22 and Windows 3.1? How would I load DOS? I remember when USB first came out and we called it 'Useless Serial Bus' but it feels weird not to have it on a PC now!

Get a boot disk, boot from disk. Agreed with the Gotek if you want to do this sort of thing more often, but a USB floppy drive to hook up to a modern system isn't a bad solution either. Expect ~50% of floppies to be dead, btw, so don't buy just one 😮

Hmm looks like I'm the proud owner of a 486. This is from around 1992/3?

More like a 386 on steroids - which would put many early 486 systems to shame.

dicky96 wrote:

last few pics
What is that case with the AT PSU at the bottom? Anyone seen it before?

I really like that case.

If you want a pretty easy way to transfer data in between a modern computer and any old PC with an ISA slot, you should look for an ISA LAN adapter. I just installed an Intel EtherLink 16TP in my 286 machine, and set it up to act as a local FTP server. You can find instructions on how do do this here: https://www.brutman.com/mTCP/mTCP.html
That software runs on any PC all the way back to the original IBM 5150!
Another option that I have utilized is the laplink cable. Just search up "Parallel port data transfer cable" and you should find one. Basically it just links two computers together (as long as they have parallel ports) and allows them to directly transfer data. It works of the dos commands "interlnk" and "intersvr".

dkarguth wrote:

If you want a pretty easy way to transfer data in between a modern computer and any old PC with an ISA slot, you should look for an ISA LAN adapter.

Well, look no further! There's one already in the box! 😎

I will agree with others here. This is a DOS box. Win95 would run on it -- my dad installed it on his 386DX/33 with 8MB RAM back in August of '95, so it works. It's just not terribly fast. The productivity gains aren't worth it, since you have other devices to use. And it won't be much of a '95 games PC. So stick with DOS.

Win 3.1 is a neat nostalgia trip, but unless you have something you want to run, don't bother. Finding drivers and getting them to work is a pain. Things SURE HAVE CHANGED since then! For ISA boards, you're just as likely to find drivers written for the chip you have, but not the board. And since there are no PCI IDs to use as a compatibility key, it means lots of freeze-ups during loading, or garbled screens, or generally flaky behavior. Also, the driver management back then was outstandingly primitive. No res / refresh rate controls at all. You want 800x600? You get an 800x600 driver. What refresh rate is that going to be running at? Who knows. Could depend on the driver, could depend on a DIP switch, could be baked into the chipset. It was a simpler time, when monitors came in two flavors -- those that could do 1024x768, and those that could do 1024x768 non-interlaced. And those that couldn't do it at all. OK, that's three.