Okay, I'm looking at that page again, and I notice
kaotikb says (my emphasis):
So my unicomp case was pretty bad and would make creaky noises when typing. So I used some electrical tape where the top case goes into the bottom part. Now no more creak and case feels more solid at the front...
As I mentioned, mine doesn't creak when I type. The
sides of the case creak when I pick it up. So I don't think kaotikb's fix will work here.
I now see I can press down on the top of the case at either end and there's 1/16" of vertical play in the middle. The case top actually bends—that's what's creaking. It looks like Unicomp's plastic isn't rigid enough, so the ends need extra support. Had the same top been made to IBM's standards, I'm guessing it would've been silent because it wouldn't bend like that.
It's funny, but my friend's Ultra Classic (which is black; mine's pearl) doesn't do that. I don't know if the top's more rigid or if Unicomp added supports to their mold (which would be easy enough to do).
I'll try attaching a couple of small wood supports to the case bottom's side walls, thin enough to fit between the case and the assembly, and just the right height for the top to rest on them. I could get fancy and match the supports' top edges to the case top's curve... I'll try this as soon as there's time and post some pictures here. I'd do a video so you could see and
hear the before/after, but I don't want to embarrass anyone at Unicomp. :?)