This is a super-great article. I still have a bunch of old P60s and P61s I got for $100 each, a decade back, and (mostly) replaced the screen-backlight ballast. They did get unreliable after a while, freezing up at random times.
There is a place where you can get a completely new motherboard for a certain old Thinkpad model, that I think I will try.
My only problem with ancient laptops is that nowadays I need 32GB of RAM to run my VMs in.