First post, by novasilisko
I'm not proud of myself.
I'm really not.
First, a disclaimer: I am quite a newb when it comes to old hardware. A lot of it is indeed older than myself. Even computer building is a relatively recent interest; I only really have been doing that for myself within the past 5 years. I am fueled not as much by nostalgia as I am by a genuine curiosity and passion for technology before my time. I am also still something of a doofus, so expect stupid mistakes 😀
Anyway, where to start? A while back, I came into the possession of a motherboard - a basically unbranded 386 motherboard; probably some industrial or embedded board judging by the unpopulated SMD position for a CPU. My interest in vintage hardware is a relatively new thing, but this board showed up at just the right time for it to plant the seeds of something dangerous.
The board had a soldered barrel battery which, of course, had leaked. I cut it off as soon as I saw it and cleaned up what corrosion I could (thankfully, no traces seem to have been too heavily damaged). It was difficult to find information on the board, but these are the closest I've found:
https://stason.org/TULARC/pc/motherboards/A/A … C-DX-5800B.html <- Very close, but the size is wrong
https://th99.bl4ckb0x.de/m/U-Z/32210.htm <- Also close, wrong size again (just a typo?), but the cache chips more resemble the real board.
https://stason.org/TULARC/pc/motherboards/U/U … -326-VER-2.html <- Matches the M-326 marking, but is a different revision and shows cache sockets instead it being soldered.
(The design of the box shares design language with Amptron's boxes, so...)
This board sat in storage for a time until something clicked inside me, and I felt a need deep down to play mad scientist and bring it to life. So (after much research and anxiety) I bought a CPU.
And I stuffed it in the board, knowing full well I probably would never get the dang thing back out again, this not being a ZIF socket... Also, at some point before this photo, my curiosity got the better of me and I tried to peel up the BIOS sticker to see what the chip itself was, and the results of that will be on display on every subsequent photo. Also, try to ignore the recently-snipped battery-replacement wires that I added then changed my mind about.
Then came more shelf-time as I shopped 30-pin SIMMs (parity, apparently, from the docs I found), and bought an ATX to AT cable adapter so I could repurpose an old ATX supply I had. But the RAM shopping turned out to not have been necessary - a friend of mine with a considerable collection of his own happened to have all the RAM I need for this thing. I'll probably get that next week. In the meantime, I decided to focus on some less-essential elements. I wanted a case! I recognized the board as no remotely modern form factor, but eventually managed to identify it as a half-width Baby AT board (which I hadn't even known was a thing). So, I bought myself an old case of appropriate era, with all the mounting holes I need, and-
No, I'm just kidding, I 3d-printed some support structure and mounted it inside my old ATX case.
I believe it was around this point that I started to lose my mind.
This is definitely going to be a make-do-and-mend sort of build. Factory-original it is not.
Around the same time, I spliced a 7905 voltage regulator into the adapter cable, to provide a -5V line derived from the -12V supply. I have no idea if this will turn out well, but it does at least measure a proper -5V, and hasn't yet burst into flames, so that's a good result so far. It's super sloppy and preliminary right now though, and I really want to redo it nicer if it actually works. I also made a replacement for the exploded barrel battery out of two CR2032 batteries and a diode (to prevent recharging). I found multiple sources saying that it's perfectly fine to put 6V into that battery line (and the voltage drop of the diode brings it down closer to 5V anyway), and I sure hope they're right.
So now, what's left? A fair bit. For bare-minimum operation, I've got the following remaining:
- Memory (here soon, at least)
- VIdeo card (preferably VGA, I guess)
- Floppy drive + controller card (friend can also provide, probably)
Although, a research goal preceding any of those is: Is the board even alive? From what I've been able to piece together, this BIOS will not give any sort of beep codes unless you have some memory installed. So, I've got my fingers crossed that when I get the RAM installed, I'll at least be able to hear a "You Forgot The Video Card, Dummy" bleep from the speaker.
So, what does the build look like right now?
Are you sure you want to know?
Well, okay. Small children and those of a nervous or sensitive disposition, please look away now.
Do you ever do something, and then stand back and look at it and go "What the hell am I doing?"
If you really want more detail, here's an annotated version.
I will continue to post updates as they arrive. If I blow up anything, my misdeeds will be memorialized on this thread for the rest of time. Although, plenty of misdeeds are already on display.
In conclusion: Sorry.