Tntmold, do you need a pc9801uv that works? I imported a couple for reasonable money from aledo auctions a while back, far far less than the scalpers on ebay etc are asking. I think your A280 has that same japanese pc98 base. They were a general office pc but are now sold as part of office cleanouts and collectors parts. You can use a japanese proxy buying service to bid/buy them as most japanese aledo sellers wont deal outside of japan. I used buyjapan. Shipping is expensive in comparison to the cost of the pc itself... eg
www.fromjapan.co.jp/en/yahoo-auctions/se...uv/-/lgk-yauc_search
For the others, the original control had a open frame computer for motion/spark control, and a PC98 (which is a japanese market only computer, not compatible at all with PC's as the rest of the world knows them) to handle display. gcode is loaded in via floppy drives, but even these are non standard, having 1Mb capacity in a 1.44 drive, but spinning at a different speed. The second drive in the pc98 can read 750k ibm format to get gcode on though. I've not had any luck at all getting a gotek or hxc floppy emulator to work on these, though HxC claim it works, it needs a add on vfo board that nobody seems to supply as the vfo signal from the motherboard is missing to use a regular floppy emu.
I got mine to boot, have spares but the above still makes it painful to use and its all so proprietory which is why I'm following this topic...
Even if the comms between the pc98 and the open frame computer (parallel cable connected) could be dumped/reversed then that might make replacement with linuxcnc possible but possibly keep the open frame as a motion control card...
Its on my todo list to do but I have a lot of things on that list to get through and its been several years in the backlog already...