IBM 4412501 / 4978 Display Station Keyboard [First Look / Teardown]

[REVENGE]

I've had this keyboard for over a year, but I didn't have the motivation to give it a teardown until today. I first became aware of this model when I watched the IBM Manufacturing Systems documentary on YouTube that depicts the process of building Model Fs (the Series/1 minicomputer and 4978 terminal's roles are explained starting at 2:45). Thereafter, it took me a few years looking high and low to finally get one.

Anyways, here it is (click for full resolution):


My unit looks to be in worse condition than the one that's owned by the Computer History Museum, but it's not the worst looking beamspring board I've seen.


The side profile somewhat resembles the Displaywriter keyboard.


These vents appear to be for air circulation for the controller board.


The IBM badge has rusted, and the adhesive has completely degraded.


Some more vents on the bottom.


This board may have spent some time outdoors.


The controller is detachable. I didn't find a solenoid.


Date codes indicate the controller was manufactured around 1979. Note the use of two 30 pin edge connectors instead of the single one that's typically found on other beamspring boards.


The support structure is made from discrete parts instead of being cast or formed from the bottom housing like some other beamspring models.


The back of the top housing has retained its nice off-white color. It is made of plastic.


In the future, I will do a full teardown and cleaning of the board. A conversion to USB would probably entail laying out a modified controller, but it looks to be doable.

Hope you guys enjoyed this first look!

[emdude]

Wow, that is spectacular! I love the relegendable keycaps.

EDIT: Correct me if I'm wrong, but that's the beam spring shown here?



Really awesome if that's the case.

[//gainsborough]

This beamspring is super cool!!

Thanks for the pics. The condition seems really good as well.

[REVENGE]

Wow, that is spectacular! I love the relegendable keycaps.

EDIT: Correct me if I'm wrong, but that's the beam spring shown here?



Really awesome if that's the case.

Yes, that's the one, although I don't have those neat looking orange keycaps.

[XMIT]

Great find - welcome back REVENGE!

[rsbseb]

How in the world did you "find" such a keyboard. I could catch the beam spring bug over this. What an amazing piece of history.

[Harshmallow]

I WANT ONE. I live in the city where these were all made and I never find any wahhhh

[seebart]

I've had this keyboard for over a year, but I didn't have the motivation to give it a teardown until today.

Haha brilliant. This is easily the Beamspring discovery forget everything else.

[Chyros]

Hahahaha it's a beamspring battleship!! That already made my day xD .

[seebart]

Hahahaha it's a beamspring battleship!! That already made my day xD .

That's right, from what I know this is the first of this type to show up here, quite a find.

https://www-03.ibm.com/ibm/history/exhi ... V4024.html

[arkanoid]

Wow nice looking board. Thanks for sharing the photos.

[MrDuul]

Wow, what a find man!

[snoopy]

Nice find! Thanks for the pics! Looking forward to more pics and progress.

[REVENGE]

Great find - welcome back REVENGE!

Thanks!

[Mr.Nobody]

When buying a computer, sometimes you can get a complimentary keyboard, but this time, you buy a keyboard and get a complimentary computer...look at this, obviously, a whole computer...

[daedalus]

HOLY FUCK SOMEONE HAS FOUND ONE OF THESE

Sorry, I've been waiting a long, long time to see a teardown of one of these...

REVENGE, I salute you sir.

Note the use of two 30 pin edge connectors instead of the single one that's typically found on other beamspring boards.

My knowledge of some of the finer points of the electronics of beam springs is a bit rusty, but I seem to recall that the matrix layouts they used would not support this many keys on a single matrix. This would seem to confirm a theory I had that the keyboard is implemented using two matrices (as does the presence of two controller chips, two 'magic capacitive chips' and what looks like a double-dose of 74-series logic). Would be very interested to see the layout of the PCB.

[REVENGE]

This would seem to confirm a theory I had that the keyboard is implemented using two matrices (as does the presence of two controller chips, two 'magic capacitive chips' and what looks like a double-dose of 74-series logic). Would be very interested to see the layout of the PCB.

I concur, and I will post pictures of the pad card as soon as I get to them. Also, I would love to see a teardown of the 254 key kanji beamspring for comparison.

[Wingklip]

Truly a magnificent specimen. Rare and few inbetween

[mr_a500]

Wow, I too have been waiting years for somebody to find one of these. They're unbelievably rare. Companies that used them must have had them destroyed - rather than reselling them - when systems become obsolete.

Hey, daedalus! Didn't you used to be ch_123? (Or am I going senile?)

[hypkx]

Congrats, really nice find that is a beautiful keyboard and the relegendable beamspring keycaps are the first one I see. #DTA7

[daedalus]

Wow, I too have been waiting years for somebody to find one of these. They're unbelievably rare. Companies that used them must have had them destroyed - rather than reselling them - when systems become obsolete.

Hey, daedalus! Didn't you used to be ch_123? (Or am I going senile?)

Yep, that's me!

[mr_a500]

Hey, I remember you from the old days, when beam springs weren't yet called beam springs, webwit was still at geekhack and ripster was still sane. (...or semi-sane)

How time flies.

[webwit]

If I remember correctly, it was daedalus who actually named them "beam springs".

[Chyros]

If I remember correctly, it was daedalus who actually named them "beam springs".

IBM names the springs "beam springs" in the patent, so if he did, he wasn't very original :p .

[webwit]

Ah yeah now I remember, he found the patent

[JP!]

Whoa nice find!

[MrDuul]

one of a kind.

[DustGod]

This is a beautiful and unique board. I really hope that it's still functional!

Also, if I'm not mistaken this would be the third known version of IBM beam spring board to feature a metal IBM badge, after the 3101 and the 3277 ones.

[Chyros]

I propose the name "beamship" .

[E3E]

Welcome to the beamship, motherf____