Compaq TC1000 Restoration
I obtained the tablet from eBay in late March 2021. Came complete with keyboard, case, and a power supply. Boots into Windows XP Tablet Edition. Internet Explorer won't load most web sites and it would be a bad idea to use it anyhow. The battery does not seem to be charging.
Can I Expand the Memory?
There is one easily-accessible RAM (204 pin SO-DIMM) module that you can reach through a panel in the back. There is another 256MB module (200-pin SO-DIMM) buried under the motherboard and it is a chore to access it. Obtained three different replacements (512MB, 1GB) for the 256MB module, but the computer would not boot with them. It's possible that the maximum RAM size for this machine is 768MB.
I managed to short the board while testing different memory modules. Fortunately, it only took out a small cable connecting the power switch assembly to the motherboard, and I was able to obtain a replacement.
Power Supply Shenanigans
After a time, the power supply burned out. I pulled a Targus Universal Charger out of storage and attached a tip that supplied the same voltage (15V) as the power supply. A week later I realized that the TC1000 wants the more common 19V and switched to the correct tip. That explains why the battery hadn't been charging!