Last year I restored a PS/2 IBM Model M 1391401 to be
used with my PC. Fortunately enough my PC motherboard still
has a PS/2 port, and one benefit is I can set in BIOS that
press any key on the PS/2 keyboard can power up the PC.
The only problem is that Model M was already water dam-
aged so I have to "bolt mod" by drilling holes on the barrel
board and use tiny screws and nuts to put the assembly back
together after removing the already fragile plastic rivets.
After all that effort, there is still problem: some
keys (specifically to me is the right bracket key and the up
arrow key) would register two clicks when pressed, which is
straight up annoying. Eventually I figured that is because
the bolts gives too much tension caused the plastic barrel
board to wrap, which is not a good thing. By taking out some
of the offending screws, the double clicking problem seems
to be fixed, at least it would not occur consistently. I
just don't want to take the assembly apart to just fix some
of the springs.
Anyway, since the long lasting double clicking made me
annoyed, I get the Beam Spring reproduction to try out the
"more premium" experience. It turns out the actuation force
of Beam Spring is much lighter (~45gf) than Model M (~75gf),
while each metal beam can be fine tuned to adjust the feed-
back. So after all I'm not regretting get another keyboard.
(At the beginning I already had a Unicomp.)
The "New Beam Spring" also get me into QMK programming,
it is actually fascinating that the keyboard controller runs
a C program to handle the key-presses. Although the 1KB
SRAM of ATMega32u2 is quite limiting if I want to implement
more complex features. They are working on a new RP2040
based controller that gives much more SRAM, a whopping
264KB. I'm very tempted to get one and program some crazy
things on it, like a scientific calculator.
