Apple Extended Keyboard II - How to resurrect

[gurghet]

I just bought an old Apple Extended Keyboard II made in Ireland in the 1989.
I want to upgrade it to a new level with a new microcontroller and a programmable firmware, I painted the pcb (thank God they didn't know double sided technology back then) and I want to wire it to a little arduino.
The fact is, this keyboard is advertised as full N-rolling rollover. But my calculations shows a 16x8 matrix + 10 dedicated keys (-32 unused path crosses) and only a handful of diodes. I can't count them since they are behind a metallic shell, but they can't be more than say 20.
Is that possible to rolling 106 keys simultaneously with only that many diodes? I think not, but I may be wrong (I'm not an electronic engineer).
So I though I could cut the tracks and add plenty of diodes (maybe even LEDs for the win).
Rewiring the microcontroller is gonna be tough, but I think most of the pins could remain in place, besides the arduino micro is much smaller than the apple chip. Furthermore I want to switch the latch/4to16 decoder with a modern i/o expander (or maybe even a daisy chain of registers for the lulz).
To mantain the vintage look I have to find a way to transform that sassy ADB to a disguised USB.
What do you think? I have zero experience with this.


Some key are easy to clean, other, like the fancy 'K' have scratches that needs some more work.

Here you can see the adb connector

The arduino micro fits just fine


I deliberately painted the tracks that connect the keys, in case I want to rewire them directly to the microcontroller. I'm also thinking about connecting all the 106 keys to individual pins of daisy chained expanders.

[rowdy]

Sounds like an interesting project with a fixed set of (probably) attainable goals - good luck!

These keyboards were apparently fantastic.  Although I wonder at Apple rotating some of the switches 90 degrees.  I guess keycap replacement wasn't a thing back then.

[gurghet]

Apparently the Apple Extended Keyboard II is not as cool as I thought

[jacobolus]

The fact is, this keyboard is advertised as full N-rolling rollover.

Where did you see that advertised? That’s plainly false, as anyone who has ever taken one apart could have told you.

So I though I could cut the tracks and add plenty of diodes (maybe even LEDs for the win).

If you really care about NKRO, you should just ditch the PCB and hand wire the switches in a diode matrix. Cutting all the traces and adding little jumper wires and diodes with the PCB still in place is going to be a pain in the butt.

Or the much easier thing would be to forget about NKRO, leave the PCB and original controller in place, wire your own controller to the wires leading to one of the ADB ports, and run Hasu’s ADB converter firmware on it.

To mantain the vintage look I have to find a way to transform that sassy ADB to a disguised USB.

USB mini and micro jacks both easily fit inside the ADB hole. Or there are various other creative sillier/fancier things you could do if you want a challenge.

Some key are easy to clean, other, like the fancy 'K' have scratches that needs some more work.

That “fancy K” is the enter key from the numpad.

Sounds like an interesting project with a fixed set of (probably) attainable goals - good luck!

These keyboards were apparently fantastic.  Although I wonder at Apple rotating some of the switches 90 degrees.  I guess keycap replacement wasn't a thing back then.

The switches being rotated 90° helps quite a bit with avoiding wobble and sticking with the extra-tall F row keycaps.

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