The factor keyboard was set up for scanning. I intend to fire off an interrupt when a key is pressed. This breaks my rule number 1: Do No Harm to the Equipment! But this piece of gear has been stripped before I got them. ( I have three of them. Good for spares!)


The switches are a To turn this keyboard into an interrupt based keypad from a keypad is run by scanning. You first have to remove all the scan lines. Then you can run a logic ground to each switch (daisy-chained). Next, I have to run a wire from each Normally Open  Contact to a connector.  Each of the switched must be pulled up to 5v via a resistor.

PROGRESS: As shown in the first picture you see how it came from the factory. In the second picture, you see it without the scan lines but still remaining power lines for the Keycaps This alone took four or five hours. I  still have to unsolder the scan lines attached to the switch, the blue and yellow wires, see the photo below. Please note the Gray and White wires as they are the keycap lamps' power.
OriginalWithout Scan LinesSwitch
I still have to unsolder the yellow and blue wiresClose up of the switch's rear.

Next, after unsoldering the blue and yellow wires, I will have to cut strip and tin with my solder pot the new black ground wire which will daisy-chain from switch to switch. The plan is to do three rows and one column on the bottom to tie the columns together.

After that feat is done I will attach the data lines to the normally open contact.

Then put plastic tie-wraps all over to hold it in place: fins!

Addendum Jan 28, 2020 I have reached a point where all of the yellow wires. I am still in the middle of adding some ribbon cable to the switches which is terminated with a DB-25F this will work out as when finished I will have one wire per switch(14) this will be wired to pin 2 of the open contact. I will also have to daisy-chain a wire  to all of the pin 4s for ground (15). Then I can use 4pins +28v and 4pins -28v for keycap lamps. After all that is done I will have to prettify the wiring again.