Revealed: The Story of the IBM Model M4 family of keyboards

[sharktastica]

Hi!

This is the story and (aiming to be) the definitive article on the IBM Model M4 and M4-1 Space Saver buckling sleeves keyboards, the keyboard that came before and largely inspired the first generation of ThinkPad keyboards (the Model M6).

Well... sort of. The story is a bit more complex but everything is explained inside! This has been one of the largest undertakings for my website, being over a month in the making, and features contributions from several awesome people! All contributions are acknowledged at the end. The motivation for this was that there is seldom (centralised) information about these keyboards. They're not particularly rare nor unheard about, but in my time looking up these keyboards, I noticed a fair few misconceptions and a lot of questions gone unanswered. Being someone who particularly loves these sorts of nichés and nuances, I thought this would be a cool thing to write about.

The article: https://sharktastica.co.uk/articles/m4_story

Enjoy! Feel free to let me know what you think.

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shark_m4_m41.jpg (879.64 KiB) Viewed 2711 times

Cheers.

[arkanoid]

Thanks for the write-up!
I also have gone through several of these. About three had non-working pointing sticks (poor durability?). Some lexmark models have a larger rectangular badge. And key pressure was quite different among the OEM manufacturers (probably due to difference in rubberdomes).

[sharktastica]

Thanks for the write-up!
I also have gone through several of these. About three had non-working pointing sticks (poor durability?). Some lexmark models have a larger rectangular badge. And key pressure was quite different among the OEM manufacturers (probably due to difference in rubberdomes).

No problem! Hopefully, you enjoyed it.

I've have a Lexmark-made one with a non-functioning TrackPoint. I haven't completely diagnosed it, but I've ruled out physical damage - the strain gauges, traces and solder joints all look good. It could related to SMD capacitors. A few other Lemark boards from the era had trouble with capacitors, including the trackball modules of both my Model M5-2s. But, I still have to look into this more.

Unfortunately, I could not find good photos of a Lexmark-badged M4/M4-1 nor anyone able to source me one. When I do get one, I'll update the article. I just don't want to write anything substantial about them without actually experiencing them.

I haven't noticed any major differences between my Lexmark, Unicomp and Key Tronic buckling sleeves keyboards. Granted my Key Tronic example is actually an M6-1, but I noted in the article that I swapped some of the sleeves between the keyboards and found little difference when compared side by side. That said, I've noticed more variance between ThinkPad buckling sleeves keyboard assemblies though. But, I have no way to properly measure this difference and talk about them, other than the passing remark I believe I made somewhere. That said, I don't own M4s from the entire timeline, so I have gaps in my experience. In particular, I'd like to find a 2000s Unicomp example for study.

[arkanoid]

Unfortunately, I could not find good photos of a Lexmark-badged M4/M4-1 nor anyone able to source me one. When I do get one, I'll update the article. I just don't want to write anything substantial about them without actually experiencing them.

There's one in this forum.
viewtopic.php?p=343326

If that's not sufficient. I will take photos of mine. Just let me know

[sharktastica]

There's one in this forum.
viewtopic.php?p=343326

If that's not sufficient. I will take photos of mine. Just let me know

Oh damn, I missed that. Cheers!

To be honest, a photo of the back would be ideal too. If you're offering and happy to do this, I wouldn't mind a photo of the back and the front (for continuality), please? Credit would be given in the same fashion as everyone else!

[Polecat]

Unfortunately, I could not find good photos of a Lexmark-badged M4/M4-1 nor anyone able to source me one. When I do get one, I'll update the article. I just don't want to write anything substantial about them without actually experiencing them.

I have a black Lexmark-built, IBM-badged M4-1 if that helps anyone. Model # 84G2525.

[sharktastica]

Update: Along with some minor spelling and grammar improvements, I've added photos of a Lexmark-branded M4. Thanks to arkanoid for offering these photos for the article!

You can go straight to it here: https://sharktastica.co.uk/articles/m4_story#OEMs

[sharktastica]

I have a black Lexmark-built, IBM-badged M4-1 if that helps anyone. Model # 84G2525.

Thanks for the offer, but I already have a UK ISO version of that particular configuration and the Unicomp version for that part number. Cheers, though.

[:Dön:]

I don't think m6 keyboard is appropriate. It looks like it is originally a Japanese keyboard, but the keys in the character section have been modified to (possibly) Arabic.
If you know it has been modified and you are describing it, it would be better to have a warning written on it.
This is because Japanese people like me will notice the mistake.
I suggest you replace it with a proper 365x image.

[sharktastica]

I don't think m6 keyboard is appropriate. It looks like it is originally a Japanese keyboard, but the keys in the character section have been modified to (possibly) Arabic.
If you know it has been modified and you are describing it, it would be better to have a warning written on it.
This is because Japanese people like me will notice the mistake.
I suggest you replace it with a proper 365x image.

Indeed, Thai language stickers had been applied to the Model M6-1 keyboard assembly by a previous owner. I've added a note to clarify this under the photo's caption. Unfortunately, this is the only fully intact Model M6-1 keyboard assembly I presently have.

In any case, thanks for bringing this to my attention.

[:Dön:]

I don't think m6 keyboard is appropriate. It looks like it is originally a Japanese keyboard, but the keys in the character section have been modified to (possibly) Arabic.
If you know it has been modified and you are describing it, it would be better to have a warning written on it.
This is because Japanese people like me will notice the mistake.
I suggest you replace it with a proper 365x image.

Indeed, Thai language stickers had been applied to the Model M6-1 keyboard assembly by a previous owner. I've added a note to clarify this under the photo's caption. Unfortunately, this is the only fully intact Model M6-1 keyboard assembly I presently have.

In any case, thanks for bringing this to my attention.

I'm sorry, the letters are Thai, not Arabic.