deskthority

I've been using a real model M for a couple of days now, after coming from a Unicomp Ultra Classic I used for 2 years, and have noticed that the spring weight for the original Model M (1993 Lexmark in this case) feels 5-10g heavier than Unicomp's buckling springs. This is after a full cleaning of the Model M too, wasn't very dirty to begin with.

From what I've been able to compare, I think it comes down to the Model M having tighter tolerances for the switch stem (Unicomp's switch stems have always felt a bit loose), and the springs on the Model M genuinely being stiffer than those on the Unicomp. It's something I'm really gonna have to get used to, has anyone else felt this or is it just me?

A Unicomp is absolutely a "real" Model M in every sense of the word. But there are sticklers who might try to argue that even a Lexmark is not some sort of "real" IBM Model M.

That said, Unicomps have always been known for feeling lighter and more pingy than earlier builds, and many people like that.

fohat wrote: ↑A Unicomp is absolutely a "real" Model M in every sense of the word. But there are sticklers who might try to argue that even a Lexmark is not some sort of "real" IBM Model M.

That said, Unicomps have always been known for feeling lighter and more pingy than earlier builds, and many people like that.

Might actually try to swap the springs because I did actually prefer the lighter springs from the Unicomp

There are a lot of factors besides the springs. I have never subscribed to the "looser tolerance/sloppy fit" viewpoint, but it may well be real. More importantly, the thin white latex mat in the Unicomps makes a significant difference over the thick black rubber ones used previously.

fohat wrote: ↑There are a lot of factors besides the springs. I have never subscribed to the "looser tolerance/sloppy fit" viewpoint, but it may well be real. More importantly, the thin white latex mat in the Unicomps makes a significant difference over the thick black rubber ones used previously.

I think I'm going to switch around a few springs from keys I don't use and compare, will report back

Nope, literally impossible to remove the springs on the Model M using the toothpick method, guess I'll just have to live with it ¯\_(ツ)_/¯

It’s possible. I’ve done Ms and Fs with a sharpened matchstick. The “chopstick method” can be fiddly but once you’ve got the hang of it, you’ll have a slow and fiddly skill you won’t need very often, for life!

I believe the "trick" is to really squeeze the spring right down into a little cylinder of wire and *then* turn it around and around until it comes off its plastic peg. When there's any air-space between the coils, the spring's too tight at its base. To make it budge, you need it good and compressed. Nothing violent, it's more a skill of coercive precision.

In my opinion, actuation weight on Model M vs Unicomp has nothing to do with springs. I have replaced some of springs/hammers on some of my Model Ms (they had damaged springs) and can't tell the difference between keys with original and Unicomp springs. The components responsible for lighter feel are blanket between hammers and membrane itself. Examples:

• Model M 122 1986 and 1987. Thick backplate with chromate conversion coating, membrane sheets are glued together and to the backplate. I've noticed that membrane and blanket (the blanket also had a strong smell of rubber) are noticeably thicker than ones on later Model Ms. Result: quieter, less pingy, but keys feel stiff, actuation is less sharp than later models.
• Other Model Ms except for the final fourth generation (controller PCB above the numpad) feel identical: 1391401 from 1993, 1392366 (1989), 51G8572 (1993). 4th gen is louder because of thinner backplate.
• Terminal Unicomp 35G4742 made in 2004. Nearly as loud and pingy with lighter actuation point as my 2010 Unicomp Customizer, but it has black rubber blanket, not that thin latex blanket as in later Unicomps. I can't tell for sure but maybe the membrane on Unicomp is thinner than on Model Ms.

Edit: typos

Quartz64 wrote: ↑[*] Terminal Unicomp 35G4742 made in 2004. Nearly as loud and pingy with lighter actuation point as my 2010 Unicomp Customizer, but it has black rubber blanket, not that thin latex blanket as in later Unicomps. I can't tell for shure but maybe the membrane on Unicomp is thinner than on Model Ms.[/list]

The newer (current) model releases from Unicomp are indeed lighter to press compared to our 1986 models.

Noticed it straight away when I first connected one to one of my PC's. The Unicomp's were all far easier to actuate compared to the ancient models. Maybe it's a combination of things that allow this to occur but I would leave it alone and let them keep on providing us all with the BEST US made keyboard.

My youngest likes her Unicomp far more than my NIB 1391401. Yes I know she's somewhat strange but she clearly loves her new Unicomp far better than any older Model-M or Razer or Corsair Keyboards (which the boys all like).

I have my FIRST model M, which i purchased new (I'm using it right now dated June 1988), a couple M terminal keyboards of later vintage, and a unicomp. I still like the old M - something about the definitiveness (is that a word?) of the click points over the unicomp.

I have gone so far as to swap the thicker rubber sheet and thicker, heavier back plate from a donor M into the unicomp (and of course bolt mod), and still can't get it to feel like the 1988 M. I feel the click points are "vague" and not as well defined on the unicomp.

My $0.02,
Keith

Out of curiosity, are the "slots" through which the spring buckle on your Unicomp clean or do they have some leftover plastic? Particularly bad examples will sound rather "crunchy" instead of clicky as the spring rubs on the plastic. To fix: remove the keycap stem and clean with a sharp blade.

I actually thought my Unicomp felt nicer than my SSKs (well okay, they're Unicomps too, just an earlier vintage and physically the heavier sort of M). In comparison, the newer black/grey/small bezel Unicomp sort of feels somewhere between my SSKs and XT Model F. Pity it developed a fault, and I'm not electronical enough to figure out what it is. I probably spilt something in it at some point, as I tend to do.