Awesome project mate, it's always cool rebuilding something you used to have.

Hope it goes well for you!

Things have actually been moving much faster and somewhat smoother than anticipated.

I have another video and writeup, covering in depth the motherboard testing mentioned above.

But that's actually not where I'm at. I'm one step ahead already. I actually already have a case. Well... a whole computer, in fact. I went to Freegeek looking for an AT case, they had an AT computer, it was $20 and... interesting to drag home through the transit system. It was not in great shape, with no screws for the cover, the drive cage fallen on the modem, and by the time I got it home, soaking wet. I cleaned it up a little, pulled out the non-essential pieces, and fired it up.

I was bracing for smoke and flames, but to my complete and utter surprise, it POSTed just fine! There was no hard drive, but I plugged in my Gotek (not with it running!), booted DOS, and ran some tools to figure out what exactly it was. I really wanted to try DOOM, but as far as I can tell DOOM won't run off a floppy and I don't have a hard drive for it. It's quite an interesting system, actually, with a DX4 Overdrive in an early OPTi 486 board. It's also clearly been upgraded over the years, with a 1995 CD-ROM drive and Sound Blaster 16 Vibra.

I almost feel bad ripping it to pieces, but there are two showstopping issues that mean I can't leave it. The first is the finicky power switch, which has to be in just the right spot for the computer to start up and makes ominous arcs and sparks if it's not. I'm hoping one side of it is good, because that's all I need for an ATX supply, but it's definitely not okay for an AT one. The other issue is the NiCd motherboard battery, which is, of course, leaking. Fortunately, it doesn't seem to have caused any serious damage, but I had to pull the system apart so I can replace it.

Finally (mostly) caught up, with a video and writeup for the above.

My horrible jury rigged (I didn't have a battery holder so I used a tealight instead) Dallas RTC seems to work and the system is able to boot from floppy. It doesn't seem to like the floppy I wanted to use, but my other one works fine as does my Gotek emulator. Weird, but okay.

I've hit a bit of a snag with the Pentium MMX 233, though. My motherboard doesn't support any explicit multiplier settings over 3.0x, but the 233MMX is supposed to interpret 1.5x as 3.5x. Setting 3.5x gives me 133MHz of actual speed for a confounding 2x multiplier.

After quite a bit of confused Googling, I came across this page. Apparently, some motherboards do not assert the BF0 line properly, leaving it floating instead of pulling it up (about 60% sure it's supposed to be up). And when the lines are left floating, the 233MMX uses its default multiplier of 2x.

Drat.

I'm tempted to bodge my own pullup resistors, but with zero documentation on my motherboard or this phenomenon I'm hesitant to try. The other option would be to look for an adapter with its own multiplier settings, or a Pentium MMX Overdrive 200. Either of those would be very cool, but they're quite rare and expensive. I think for now I'll stick with the Pentium 133.

Haven't looked at the vid's or writeup's yet but like where this is going.
You got lucky with a 486 for $20 as well! I wouldn't feel sorry about parting it out. You can always keep an eye out for another case and re unite the 486 later down the track.

I'd go with the original CPU and motherboard, later if you want you can try upgrading the CPU with your spare board. My thinking is because I also still have my first PC a 486 Dx2/66 and while I could upgrade the CPU and the SB16, I cant bring myself to do it. THAT CPU and THAT soundcard are all part of the nostalgia now.
I ended up getting a second 486 that I've upgraded, but I still use the DX2/66 more.

I assembled the system! Well, actually I assembled it a few days ago, but it took me this long to get everything together. Here's the video and the writeup.

This was probably the worst build I've ever done, yet at the same time the best build I've ever done. Building PCs today is definitely easier than it was back then. There are so many builder-friendly features now that I guess just never occurred to anyone back then. I fought with everything from unkeyed connectors to uncooperative fan mounts, to an impossible drive cage, to a total inability to manage cables. I remember some of this, but experiencing it again is something else entirely. At the same time, it was a fun build because of how challenging and simply different it was, and I'm really quite happy with the end result.

I've been playing with the system quite a bit and have already tried some games, but a proper report on those will have to wait for another day.

chinny22 wrote:

Haven't looked at the vid's or writeup's yet but like where this is going. You got lucky with a 486 for $20 as well! I wouldn't […]
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Haven't looked at the vid's or writeup's yet but like where this is going.
You got lucky with a 486 for $20 as well! I wouldn't feel sorry about parting it out. You can always keep an eye out for another case and re unite the 486 later down the track.

I'd go with the original CPU and motherboard, later if you want you can try upgrading the CPU with your spare board. My thinking is because I also still have my first PC a 486 Dx2/66 and while I could upgrade the CPU and the SB16, I cant bring myself to do it. THAT CPU and THAT soundcard are all part of the nostalgia now.
I ended up getting a second 486 that I've upgraded, but I still use the DX2/66 more.

I definitely got lucky with the 486. Finding anything earlier than about 2005 is surprisingly difficult around here- I think most of it has already been thrown out. To be honest, though, I'm thinking about selling the 486 board if I can find a buyer. I don't have a lot of space, and I already have a system without a home- the "spare parts build".

Speaking of which, the Pentium MMX 233 works in the spare board. I tested that a while back and it's recognized properly and everything. That's not entirely surprising considering that it's at least two years newer. It'll probably be an objectively better build, with a newer chipset, USB, more storage (8GB CompactFlash), and a Rage XL (in the mail). I might actually build this one in my dead, pre-desecrated XT. It'll be a bit of an odd build, and I'm still not sure what I'm going to do with it, but I think it'll be a pretty nice PC.

I guess this build isn't entirely a purist one since it's as much about building what I didn't have as what I did have, with some things I absolutely want to keep. The pieces I really want to keep are the motherboard (naturally) and the graphics card (for some reason). The processor I'm kind of on the fence on. The Pentium 133 is 100% original and it's been through hell, but I remember seeing 200MHz and 233MHz Pentiums back in the day and thinking they were just so cool. I was going to try to fix my Sound Blaster 16, but I really like the sound of the AWE64 so I think I'll keep it. I know that a younger me would have absolutely taken the AWE64 over the SB16, for the higher number if nothing else.

This is going to be a somewhat messy post but I've already written two other writeups of it...

I installed a Voodoo2 accelerator! Well, I did that a week ago, actually, but I finally got around to properly testing it.

That's the seller's picture- I was so excited when I finally got the card in my hands that I installed it right away and forgot to take pictures.

I tried a few games and, well, it's a mixed bag. Quake was excellent. With the 3dfx card in, I could do twice the resolution and still have a much smoother game- I think it was a steady 60FPS! I thought it ran okay in software mode but with the accelerator it really is dramatically better. I still haven't figured out screen capture and I don't have a proper capture setup, so all I have are these lousy cropped photos.

Quake II was iffy. Sometimes it was a similar dramatic improvement- a far smoother framerate despite running at twice the resolution- but certain effects made the game really chug along. Half-Life was far better with the card than without, going from basically unplayable to playable, but still not good. I think these games are CPU-bound and the Voodoo2 isn't able to stretch its legs.

Considering the age of the system in relation to the release dates of the latter games, it's not entirely surprising. Tech sure did move fast back then!

I also installed a drawer which I got off eBay, but to be honest it's kind of ugly so I'm not sure if I'll keep it (though I don't have anything else to put there at the moment). I tried adding a USB card but there was some kind of incompatibility which led to a "fun" evening of troubleshooting where I nearly tore my hair out because I thought it was the RAM.

I do plan to test some earlier 3D games that support Glide and are more contemporary with the original computer. I might also upgrade to a 200MHz Pentium, which should be quite a bit faster.

I think that's it for now. I have a list of games I want to try but I'm kind of waiting on having a proper capture setup so I can record the result.