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

Posted: 03 Jun 2017, 03:50
by 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):
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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.
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The side profile somewhat resembles the Displaywriter keyboard.
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These vents appear to be for air circulation for the controller board.
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The IBM badge has rusted, and the adhesive has completely degraded.
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Some more vents on the bottom.
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This board may have spent some time outdoors.
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The controller is detachable. I didn't find a solenoid.
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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.
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The support structure is made from discrete parts instead of being cast or formed from the bottom housing like some other beamspring models.
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The back of the top housing has retained its nice off-white color. It is made of plastic.
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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!

Posted: 03 Jun 2017, 03:59
by emdude
Wow, that is spectacular! I love the relegendable keycaps. :o

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

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Really awesome if that's the case.

Posted: 03 Jun 2017, 04:01
by //gainsborough
This beamspring is super cool!!

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

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

Posted: 03 Jun 2017, 04:42
by REVENGE
emdude wrote:Wow, that is spectacular! I love the relegendable keycaps. :o

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

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

Posted: 03 Jun 2017, 04:43
by XMIT
Great find - welcome back REVENGE!

Posted: 03 Jun 2017, 04:59
by 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.

Posted: 03 Jun 2017, 05:26
by Harshmallow
I WANT ONE. I live in the city where these were all made and I never find any wahhhh

Posted: 03 Jun 2017, 06:51
by seebart
REVENGE wrote: 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. :o :shock:

Posted: 03 Jun 2017, 08:26
by Chyros
Hahahaha it's a beamspring battleship!! That already made my day xD .

Posted: 03 Jun 2017, 08:30
by seebart
Chyros wrote: 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

Posted: 03 Jun 2017, 09:16
by arkanoid
Wow nice looking board. Thanks for sharing the photos.

Posted: 03 Jun 2017, 13:15
by MrDuul
Wow, what a find man!

Posted: 03 Jun 2017, 14:01
by snoopy
Nice find! Thanks for the pics! Looking forward to more pics and progress.

Posted: 03 Jun 2017, 21:03
by REVENGE
XMIT wrote: Great find - welcome back REVENGE!
Thanks!

Posted: 04 Jun 2017, 00:33
by 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...
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Posted: 05 Jun 2017, 22:05
by 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.

Posted: 06 Jun 2017, 05:04
by REVENGE
daedalus wrote: 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.

Posted: 07 Jun 2017, 02:53
by Wingklip
Truly a magnificent specimen. Rare and few inbetween

Posted: 11 Jun 2017, 12:06
by 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?)

Posted: 11 Jun 2017, 19:24
by hypkx
Congrats, really nice find that is a beautiful keyboard and the relegendable beamspring keycaps are the first one I see. #DTA7

Posted: 12 Jun 2017, 11:41
by daedalus
mr_a500 wrote: 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!

Posted: 12 Jun 2017, 12:27
by 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.

Posted: 22 Jun 2017, 11:35
by webwit
If I remember correctly, it was daedalus who actually named them "beam springs".

Posted: 22 Jun 2017, 12:59
by Chyros
webwit wrote: 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 .

Posted: 22 Jun 2017, 13:46
by webwit
Ah yeah now I remember, he found the patent ;)

Posted: 22 Jun 2017, 17:47
by JP!
Whoa nice find!

Posted: 20 Jul 2017, 13:58
by MrDuul
one of a kind.

Posted: 20 Jul 2017, 15:06
by 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.

Posted: 20 Jul 2017, 15:41
by Chyros
I propose the name "beamship" Image .

Posted: 20 Jul 2017, 15:59
by E3E
Welcome to the beamship, motherf____