deskthority

You're certain that there was no logo on the bottom of the switches? Do you know what keyboard this was and who had it? I presume no photos of it still exist, such as ones that might show a manufacturing date of the case or controller IC.

I don't even know that "true" "ICL switches" are even the Ericsson ones; it may be that they were the other type shown above with the Stackpole-like helical actuator spring. It's very hard to keep track of knowledge across forum topics; in fact, I tried to find a geekhack post earlier (one where I think you corrected me on Matsushita vs Matshita) that Google is adamant doesn't exist. Interestingly, though, having just checked right now, the forum search found it straight away.

For the Stackpole design, see [wiki]Stackpole discrete switch[/wiki] / Fixing a Stackpole Momentary Keyboard / Key Pad Switch.

Muirium wrote: ↑The Ampex is an NMB/Hi-Tek Space Invader board. Nicer than MX! I'm typing on another ISO one right now.


vs.


Nice catch!

Are these clicky?

My black space invaders are very clicky indeed:
The white ones are linear, according to the wiki.

http://deskthority.net/wiki/NMB_Hi-Tek#Colours

The white ones, no. Basically:

Clicky: trailing arm provides a click, visible at the back of the slider; wide separator bar
Linear: no trailing arm, and wide separator bar (per the white switches above)
Tactile: no trailing arm, and narrow separator bar

The pictures on [wiki]NMB Hi-Tek[/wiki] should make this clear although that page still needs a lot of work. The definition of "eyes" plus examples would be well served by diagrams showing exactly what "eyes" are (2, 1, and 0) as it's not always clear.

Daniel Beardsmore wrote: ↑A photo of the controller IC would be interesting — and any markings on the PCB. i.e. is it contemporary with the Loewe keyboard?

Here pics I just made, don't know if that's enough to date the board.. nothing like a date is in or out.

Stickers and PN Controller paper sticker on front pcb marking back pcb Desoldered one switch, one without diode cause others have one with.
There is no brand back the switch, nor front.

D8748 is an Intel microcontroller, so that's not 1987. L2478212S, if taken to read week 12 of 1982, fits the same year as what's written on the smaller ICs.

So, it appears to be 1982, and contemporary with the Loewe keyboard (ca. 1984). Loewe sounds German (and the text on the Loewe keyboard is in German), and the Philips keyboard is made in Germany.

Both tie in well together. Sadly, neither one suggests a switch manufacturer.

Finally, the patent for RMD 973 series:

https://worldwide.espacenet.com/publica ... 3027B&KC=B#

Helps if you can read Swedish. Interestingly the patented version appears to have the diode under the stationary contact, and uses it as a terminal, making it inline with the circuit just as with RAFI RS 76 M. (Normally the diode is a wholly separate entity.)

The switch has a "time-delay mechanism", whatever that means.

Daniel Beardsmore wrote: ↑Finally, the patent for RMD 973 series:

https://worldwide.espacenet.com/publica ... 3027B&KC=B#

Helps if you can read Swedish. Interestingly the patented version appears to have the diode under the stationary contact, and uses it as a terminal, making it inline with the circuit just as with RAFI RS 76 M. (Normally the diode is a wholly separate entity.)

The switch has a "time-delay mechanism", whatever that means.

posibly some early form of hardware debouncing? I cant think of what else that would possibly mean.