Okay! First things first, yanked out the barrel battery.
Yep, good call. A little CMOS amnesia never hurt anything.
So I plugged the Pentium PSU in and it seemed to work fine. I decided to swap it into the 386 and see if that would fire up. Easy job right? Well ... no, not really.
Firstly I forgot how AWFUL these old towers were to work on. THEY ARE TRULY HORRIBLE. I remember *hating* ATX cases when they first came around, but what was I thinking?! These are a billion times worse. There's no access anywhere, there's no clips or quick-releases, everything is screwed in or riveted or soldered from *all possible sides*, no sign of ergonomics... ugh. If you're used to any semi-modern swing-open design, even some proprietary thing like Dell or Lenovo, there may be some fiddly bits but YOU HAVE NOTHING on this crap. Wow.
Look at this for example - this is the switch for the power cable on the 386. I'm supposed to get my fingers in there to yank off 4 spade connectors. Somehow.
WHERE DO THE FINGERS GO.
Eventually I got them off by prying the front of the case partway open (4 screws and some brittle plastic clips), and then discovered THIS. THIS EARTHING SCREW.
Which is screwed in from the inside. SOMEHOW. There is no way to get ANY TOOL in there. I had to take it out by rotating the threaded end with PLYERS. WTF.
Here is the case stripped down a little. You can see I took the 3.5" drive caddy out, which would have made room to undo ^^ THAT screw, except it was impossible to take out the OTHER screws that held in the caddy itself from the *front* WITHOUT taking the PSU switch off because there wasn't enough slack in the cable to pry the case front off enough to get a screwdriver on THOSE which meant - okay fine I'll stop.
You get the idea! I am completely baffled at how this thing was put together in the first place!
(BTW if you think that carpet looks like it's the perfect color and texture to invisibly camouflage dropped screws or washers... well, you're right, it totally is.)
The Pentium system was almost as bad to disassemble but at least the motherboard tray was removable which made access a lot easier. Incidentally as I was rolling the case around all axes removing screws, this chip FELL out:
Okay... I don't know where that came from, I don't see an obvious spot where it is missing on the motherboard but who knows. Maybe it's from something else. Luckily I don't particularly care if that one works or not, but it would maybe be nice to have for backup.
Installed the good PSU in the 386. Hooked everything up, but the power switch is soldered on to this one instead of using connectors. I was FAR too lazy and tired at that point to get out my iron & heat shrink so I just left the second switch in, hanging. I put as much of the 386 back together as I needed to fire it up, plugged it into a monitor, dug out an AT keyboard adapter, connected everything, hit the switch, and ...
BANG. Sparks. Burning plastic smell. OFF. Unplug.
At this point I figured I blew a cap or something and was ready to call it quits. But (a) it seemed to stay on for a bit after the sparks flew, and (b) then I saw this:
That's right, the uninsulated, unearthed power switch which I left dangling shorted itself on the side of the case. (See where the white wire is also blackened?) Whoops. My bad.
Yeah, I'm not smart enough to give up after that. Now I *really* needed to know if it would work. A roll of electrical tape and a grounding screw later and I was ready for attempt two.
...banished to the balcony this time, away from my flammable carpet and furnishings! NO, I don't have a fire extinguisher or anything, why would I???
Anyway, I fired it up and it miraculously seems to have suffered no ill effect. It made encouraging POST-y noises and I was able to bask in the gloriously awful green-purple-red of the oldschool BIOS.
(Seriously, who picked these colours? Who looked at that and thought it was a good idea??)
I even got it to boot FreeDOS from a floppy, so looks like it works! For the first time in about 20 years I have a working 386. Now what?
...and it only took me three times as long as I thought it would and left my living room a disaster to get going.
NEXT TIME on XJAS RESCUES SHIT FROM THE GARBAGE:
20 kilos of MINT rackmount NAS, charming the snakiest of KVMs, what the heck is a Logic Pattern Generator??, and not one but TWO of the very best PowerPC machines EVER BUILT. Don't touch that dial!