Vintage Cortron 81

[mogo]

Was trawling through some military surplus sites and came across this Cortron 81 keyboard with some really REALLY cool spherical keys with both English and Japanese Kana legends. Specifically, these appear to be Katakana, not the more cursive Hiragana characters.

It's selling for $35 USD + shipping. I can't find any info on what kind of switches it uses, possibly Hall effect, but that's a guess based on snippets of suggestions I've found while doing various google searches for information.


More images of the board here: http://www.surplussales.com/ComputerAccess/Close-ups/eqp-55-500135.html
I love the brown and cream keys. It's gorgeous and the price is right, if only the keys were transplantable, but I doubt they are. Maybe someone here has reason to order one, and then share their experience with a teardown/resto?

[0100010]

Licon Switch - magnetic pulse coupling // not a bad price @ $35

[mogo]

Which apparently look like this:
(credit to HaaTa, original post on DT)

Thanks for the info, 34!

[HaaTa]

Might also look close to this
https://plus.google.com/photos/113845661925823397356/albums/5735481286874647233/5735475558218552162?pid=5735475558218552162&oid=113845661925823397356


Both of these switches were designed/made by ITW (Illinois Tool Works). Patents are around.
Licon (which later became Cortron) is a subsidiary of ITW, hence why they use their switches.

ITW made quite a few variants of the magnetic pulse switches. I have examples of at least 4 of the variants.

[dorkvader]

Not to mention the NIB univac cardpunch KB below it.
$125 (free shipping) but it's NIB!

Excellent find mogo, thanks for sharing. I think we'll buy up their stock pretty quick

[Parak]

As per HaaTa iirc that particular Univac uses microswitches that make the keyfeel kinda bleh. So, hardcore collectors or somesuch only need apply.

[mogo]

Glad to be of help! If you get it, please show it off to us Dork

[dorkvader]

As per HaaTa iirc that particular Univac uses microswitches that make the keyfeel kinda bleh. So, hardcore collectors or somesuch only need apply.

I think it's this one:
https://www.flickr.com/photos/triplehaata/sets/72157637897439135/

[engicoder]

I was intrigued by this switch type and did some digging some time ago. I think the relevant patent is 4,227,163. It may be contactless, much like a hall effect switch, but relies on  the magnetic saturation of a transformer to complete or disconnect the circuit. From the patent:

The analog type of keyswitch illustrated in FIG. 1 utilizes a closed loop, preferably a toroidal-shaped magnetically saturable magnetic core 70. In this type of switch the magnet 42 is located adjacent the core 70 when the plunger is not depressed. A U-shaped, flat drive line 72 and a U-shaped, flat sense line 74 are threaded through the core so that the sense line may pick up an electromagnetic signal when a pulse of current is supplied through the drive line, providing the core 70 is not magnetically saturated. When the plunger is in its undepressed position, the core 70 will be magnetically saturated and thus pulses of current on the drive line will not produce output signals on the sense line. However, when the plunger is depressed the magnet will move away from the core thereby allowing the core to come out of magnetic saturation so that the drive line signals will now be transformed to the sense line.

There is also a patent where they talk about a method of implementing n-key rollover with this switch type...way back in '74.

I've thought about getting one and experimenting with developing a controller. The old british nascom-1 used a keyboard with these switches and the manual has a good discussion and the schematics they used.

[0100010]

This is the page I found on it when looking up the patent number on the PCB : http://www.vintage-computer.com/vcforum/archive/index.php/t-26718.html?s=160cd2b0d30f8f072a907686cb306c1a

[engicoder]

This is the page I found on it when looking up the patent number on the PCB : http://www.vintage-computer.com/vcforum/archive/index.php/t-26718.html?s=160cd2b0d30f8f072a907686cb306c1a

I think that is the page that led me to the Nascom information

[dorkvader]

Here's some more info on how they work that Haata wrote up:
http://deskthority.net/keyboards-f2/rafi-magnetic-pulse-switches-t6216.html#p120902