deskthority

I'm liking the Teensy and the multimeter. This is a Kaypro 4 keyboard I picked up.
The switches appear to be most likely SMK J-M0404 based on the black switch bases, though from what I've read some Maxi Switches have a black base as well. There is some chipped paint a a little rust but cleaned up pretty well.

Traced out the matrix with the multimeter again, desoldered the relevant ICs (was careful and they could be replaced to restore the board to original configuration without difficulty) and wired the Teensy. I did find that both Shift keys are connected to the same row and column. I guess they figured it didn't matter.
I connected the Caps Lock LED and also used the on board piezo to provide a keystroke click - connected to the Teensy it's pretty quiet though and the keys themselves are louder.
The board has a limited key configuration, no F keys, etc, but I do like these old boards! I do have the key matrix and IC pin diagrams I used and if anyone is interested I can post them.

Whoa, nice job! That board does look pretty cool.

Looking good!
Is there something no I should pay ttention for when measuring out a matrix?
I never did it beforehand, but have to sooon.

OldIsNew wrote: I'm liking the Teensy and the multimeter.

I'd say so. Just keep doing this beacuse it's awesome! The Kaypro 4 is a classic, those SMK aren't my favorite but who cares. Great work!

I loved my Kaypro 4 back when I had one in 1984/1985. Though I gotta say, the 64KB RAM limitation became frustrating after a while. It put pretty severe constraints on the size of my Turbo Pascal programs.

Thanks for the encouragement, everyone. It is fun to be able to actually use some of these old keyboards.

Phenix wrote: Is there something no I should pay ttention for when measuring out a matrix?
.

I don't have any special tricks really, it just takes some time to figure out which keys are connected to each other - it's not always obvious. I just gradually figured out the rows and columns and then checked which IC pins they connected to. There were a couple things I did find helpful. One, kind of obvious I guess, was using the audible setting for continuity testing - much easier than staring at the meter. Another is to make sure to pay attention to the location of the diodes and testing continuity from the ends of the diodes, rather than through them - again just so can use the audible continuity testing rather than have to watch the meter. I don't know if his applies to all meters, but at least on my cheapo one if there's any significant resistance (like though a diode) it won't beep, just reads the resistance.

OldIsNew: Have you already posted the key matrix / ic pin configuration for your Kaypro 4 keyboard? If not, could you? I just obtained 2 of them and could use this. Thanks a million!

Give me a bit to look! I must still have the IC pinout somewhere. I will be happy to help if i can!