An IBM M keypad that feels like an F.

depletedvespene · 01 Dec 2017, 03:19

This is supposed to be the M version of the IBM 4704 Model 100 keypad. It sports the gray IBM oval logo, has a plastic backside and M's flip-out feet, and even sports an SDL plug.

: IBM Modem M 4704-Model-100-like, frontside.; F-or-M-1_th.jpg (362.19 KiB) Viewed 4826 times

: IBM Modem M 4704-Model-100-like, backside.; F-or-M-2_th.jpg (303.61 KiB) Viewed 4826 times

: IBM Modem M 4704-Model-100-like, label (tampered with, but what the heck).; F-or-M-3_th.jpg (282.72 KiB) Viewed 4826 times

Yet... typing on it feels quite closer to typing on a Model F than on a Model M.

Why?

: IBM Modem M 4704-Model-100-like, are those regular flippers or not?.; F-or-M-4_th.jpg (288.49 KiB) Viewed 4826 times

A quick topside look at the springs doesn't yield much, so... let's open it.

: IBM Modem M 4704-Model-100-like, internal plate front view.; F-or-M-5_th.jpg (476.55 KiB) Viewed 4826 times

Frontside doesn't tell us much.

: IBM Modem M 4704-Model-100-like, panel's backside. Oh, moderately shiny!; F-or-M-6_th.jpg (468.74 KiB) Viewed 4826 times

Is this a SHINY backplate? Like Model F units had?

: IBM Modem M 4704-Model-100-like, panel's backside with a better view of the controller.; F-or-M-7_th.jpg (532.72 KiB) Viewed 4826 times

The controller looks like an M-era model...

: IBM Modem M 4704-Model-100-like, plate sandwich.; F-or-M-8_th.jpg (313.75 KiB) Viewed 4826 times

... the sandwiched foam, on the other hand, screams of Fness.

And with that, I stop. If I open this up, I'll surely won't be able to put it back together.

I bought this keypad as a fun toy, to use as a side pad or a sophisticated game pad of sorts; I did not expect it to bring this pleasant surprise. What a fun... hybrid? intermediate evolutionary step? keypad.

I now kinda want to procure one of the later models, manufactured by Lexmark, if only to see if typing on it would feel more like a Model M than a Model F.

arkanoid · 01 Dec 2017, 04:16

If somebody makes a PCB for this, then it would be able to make a semi-model F.
Or if you want a bigger project, then you can try to build build an ergodox model F using two keyboards.

By the way, feet are different from those of regular model M as I remember.

Darkshado · 01 Dec 2017, 05:43

Hard to tell with the flash, black flippers would point towards an F, white are a pretty surefire sign of an M.
139* part numbers are associated with model M.
The controller photos clearly show two superposed membranes; it should be possible to lift the foam slightly and see the PCB on an F as well.
Individual barrels on an M are peculiar, are there other known examples?
We did see that plastic barrel plate style F typewriter assembly not long ago, so there is some overlap in the techniques on both models.

xueyao · 01 Dec 2017, 08:22

It's definitely a Model M, I've got one and opened it up before and it's membrane is exactly like an M. If anyone could design a PCB I'll love to test turning this into a full F.

seebart · 01 Dec 2017, 12:06

Darkshado wrote: ↑We did see that plastic barrel plate style F typewriter assembly not long ago, so there is some overlap in the techniques on both models.

That's the interesting part, thanks for posting depletedvespene!

andrewjoy · 01 Dec 2017, 13:54

IBM, would it really have cost that much more to keep the M like this!

You had the tooling to automatically assemble F's i have seen the vids

.

Does switching to heat melted plastic really same that much money ?

And don't forget , you can make almost all the spare parts for your existing customer who have F's on the same production line!

PlacaFromHell · 02 Dec 2017, 00:24

Great find! Those keypads have a really distinctive feel. Maybe is not the same, but mine (that we talked about months ago)
has a strong bottom feeling like short travel switches (for example the short travel futabas), accompanied by a TAP sound. Anyway, would be interesting see it working. Do you checket his compatibility?

depletedvespene · 02 Dec 2017, 00:30

The one in the pictures is already in active usage by my son. I haven't started using the other one (as I want to clean it a bit first), but I expect it to work just as nicely. At least the typing feel is the same.

IIRC, your unit must be Lexmark made - mine are a bit older, IBM made, and it may be that your unit does have a typing feel like the regular Model M keyboards. We need to determine it for sure.

PlacaFromHell · 02 Dec 2017, 03:52

Mine is blue label, so your board is older. I put it in front of my daily use battle cruiser and they definitely sound and feel different. What I mean is that these "planck" IBM's are a whole different world.

snuci · 02 Dec 2017, 04:17

This looks to be similar to the "hybrid Model M/F" in the screenreader keypad here: photos-f62/ibm-model-m-os-2-screen-read ... 13488.html

PlacaFromHell · 01 Jan 2018, 23:22

Sorry for reviving this, but I just noticed today that mine is a M/F too. You can easily notice that by the swinging of the barrels. I did not expect that of a blue label, but it's awesome anyway.

tentator · 09 Dec 2018, 11:23

I also found one and can confirm the switches really snap nicely, much more like an f than an m.. So theory is that's because the metal plate joints?

Spoiler:

Tent:wq

John Doe · 10 Dec 2018, 02:06

Is there any f50's PCB existing? Maybe could make some mod for an M50.

depletedvespene · 11 Dec 2018, 13:13

tentator wrote: ↑I also found one and can confirm the switches really snap nicely, much more like an f than an m.. So theory is that's because the metal plate joints?

Yup, that's what I think.