Inside a Commodore 128D keyboard

[arapineau]

I have this pretty pristine white thing




Sadely I don't have the original box but it nevertheless came with what I presume was the original two plastic bags.
Curious to see what is inside? Great because I also have this




So uh




That's certainly dirty and there is some funny things happening on the PCB, but we have a bigger problem here



Why Commodore?! WHYYYYYYY?
Complains about Mutsumi aside, some things didn't went well durring the disassembly and... well you'll see.



The switches are a mix of Mitsumi hybrid switches and standard mechanical for the latching ones.






And now the elephant in the room: the latching switches are inserted in the PCB through drilled holes and wires are soldered directly on their pins.
It's a pain because you have to desolder them in order to separate the PCB from the sliders, AND as they twisted those wires,
you have to heat the solders for a long time with your soldering iron in older to suck the solders out... and melt the plastic of the switches!

What a great design... thank you Commodore and thank you once again Mitsumi. Now I am not sure I want to clean the keyboard of my C64 anymore.



Anyway after melting some ABS





Some after some scrubbing




Here is my ugly hack to protect the already damaged switches: six wrap wires, very state of the art suff!




Anyway, some screwing latter only the keycaps remain.



Speaking of keycaps, there are of two kind:
 - the "white" one, double shot ABS with grey printing on some (it would have been cool to have triple shot ABS though)
 - the grey one, printed ABS PBT? (Ttey don't dissolve in acetone)



It apprears however the latching mechanism of the switch under ASCII/DIN key is damaged,
and either there weren't any plastic grips with the numpad 0 key to grip the stabilizer or they went down the drain durring rinsing,
along side some other small plastic damages.



Oh well, one can't always win.

[rpiguy9907]

Are you sure the gray keys are ABS? They never seem to yellow.

Taking apart a 128 keyboard is indeed a pain. The C64 had one of those soldered keys, I can’t imagine dealing with three of them.

[libertycannon]

nice!

[arapineau]

Are you sure the gray keys are ABS? They never seem to yellow.

My bad I thought they were yellowing but I confirmed they aren't ABS as they don't dissolve in acetone.
I really need to get better lighting :/

Taking apart a 128 keyboard is indeed a pain. The C64 had one of those soldered keys, I can’t imagine dealing with three of them.

I really don 't understand why they didn't use some sort of small mezzanine boards, 1 per switches.
I mean, sure the C128 was supposed to be cheap to produce but come on. Would using small mezzanine boards would have been that much expensive than hand soldering the switches?

[Findecanor]

Wow. The wires from the cable are all soldered individually to the PCB. What a chore!

The entire C64 matrix of 8×8 keys plus the additional keys of the C128 are connected directly over that cable. Not long ago I learned that the C64 matrix is scanned by the CPU on the same 16 I/O pins as the joystick ports. Keyboard functionality is therefore limited when you use the joysticks. Pressing Fire on joystick 1 presses the space bar ... , and you could damage the I/O chip if you connect a Sega gamepad and press a key.