Datalux Keyboard Teardown

Ok. This was an impulse buy. But when it arrived it was missing two keycaps, so I got a refund. That means I'm off the hook from the impulse buy right?

Anyways I saw this pretty thing on ebay: the Datalux MURUC

It was so clean, and look at that funky shape!!! This one was 85 bucks, but I wasn't going to shoot for anything above $15. Anyways, it is widely considered a bad, mushy mechanical keyboard. But like I said, impulse.
So here is the one that I got, and then was refunded for.

As you can see, mine was not as beautiful. It came with a bunch of missing keys. It also smelled like veritable trash heap (as opposed to stack). So.. I decided that it was not worth it to fix up; so I tore down. Here are my electromechanical archaeological findings:

The keyboard uses these surface mount MEI white linear switches. I have never heard of this brand! They are pretty smooth, but also very stiff (maybe like 70 to 80 grams). Also only expect key travel of 3 millimeters or so.

The single sided PCB appears, next to the space bar, to have a date code of 30th week of 1990, which I believe. Another interesting thing, is that I only see ghosting rollover diodes near the space bar and nowhere else. I don't have a picture of the traces and the soldermask on the bottom so you will have to believe me. Also notice the oscillator is Earth-grounded. Look at that linear resistor package too!

Additionally, the main integrated circuit is a Signetics  jobby with date 1980. I could not find any specific information on this part number, but I did find an interesting microprocessor data manual from 1983. I can't seem to find any chips with the MC designation, as most have the SC label.

I am in the process of cleaning the remaining keycaps in case I need them for a project.