Hmmm, and I still have my old DOS/286 machine, complete. I kept it because it has my early Expro EPROM/device programmer attached, and I wanted to keep that available.
Wonder if it still works?
Should we turn this into a 'show us your oldest working PC' thread?
I have an original IBM XT too.
My oldest is a Compaq Portable III, which I got at a thrift store in 1995 for $20. I considered it a real bargain at the time. It's been with me ever since.
I recently did some upgrade work on it:
About five years ago the Lithium KeePer battery finally died, so I replaced it with a coin cell holder and a LIR2032 (plus a hacked in trickle charge circuit).
Ultimately this proved unreliable, so I finally did away with it and the original MC146818 RTC/RAM chip. I replaced them with a brand new (direct from Maxim) Dallas 12887+ which should last another 20 years. (Note: Not some of my best rework, I'll admit. That black solder mask scratches so damn easily! I ended up having to cut the leads off the MC146818 and several passives, hence all the scuffing.)
I also upgraded the 16450 UART to a 16550D and the 80287 to a 80287XL (which is really an 80387).
Throw in a 1GB Industrial CF Drive and we're really rolling!
That was a pain in the ass to get working, let me tell you... Even though this was one of the first PC's to have an onboard IDE interface, basically I was limited to the original hard drive types by the BIOS, with no way to set anything custom. Thankfully XTide saved the day! It's this fantastic open source ROM BIOS that allows old XT and AT machines to access large hard drives. I simply flashed it to an EPROM and popped it in the empty ROM slot on the ISA Ethernet card I was installing in the machine and... Voila!
So now, the only thing I could really add to the machine would be more RAM. Unfortunately Compaq used some weird custom format for the RAM expansion (basically little expansion boards) so unless I either create my own PCBs for that *or* install an ISA RAM card, I'm stuck with 1MB.
Anyway, here's what I've got installed:
NI GPIB AT-GPIB/TNT (PnP) ISA Card
3com Etherlink III ISA Card
XTide Universal BIOS
i286 + i387
1MB RAM
1GB Industrial CF Drive
5.25" 1.2MB Floppy
3.5" 1.44MB Floppy
640x480x16 Grayscale Plasma Screen
CGA Graphics
Right now she sits on a desk and acts as a GPIB controller, running simple measurement programs written in Qbasic 4.5; the results and stored to a network share.