geekhack
geekhack Community => Keyboards => Topic started by: arapineau on Sat, 09 February 2019, 15:28:07
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I have this pretty pristine white thing
(https://i.imgur.com/1QVoh7Y.jpg)
(https://i.imgur.com/gzAt9rj.jpg)
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
(https://i.imgur.com/DkcyrZ6.jpg)
(https://i.imgur.com/hwhrRMM.jpg)
So uh
(https://i.imgur.com/S9eqH2D.jpg)
(https://i.imgur.com/EaXGO0y.jpg)
That's certainly dirty and there is some funny things happening on the PCB, but we have a bigger problem here
(https://i.imgur.com/366BBE9.jpg)
Why Commodore?! WHYYYYYYY?
Complains about Mutsumi aside, some things didn't went well durring the disassembly and... well you'll see.
(https://i.imgur.com/SXqmFg9.jpg)
The switches are a mix of Mitsumi hybrid switches and standard mechanical for the latching ones.
(https://i.imgur.com/JxygwyP.jpg)
(https://i.imgur.com/UZfgzrw.jpg)
(https://i.imgur.com/wHypC2l.jpg)
(https://i.imgur.com/y9hQbOX.jpg)
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.
(https://i.imgur.com/M1SHfLQ.jpg)
Anyway after melting some ABS
(https://i.imgur.com/J8rJERD.jpg)
(https://i.imgur.com/wexTKe8.jpg)
(https://i.imgur.com/CDUBsFd.jpg)
Some after some scrubbing
(https://i.imgur.com/rGnJ90C.jpg)
(https://i.imgur.com/JUaEGKr.jpg)
Here is my ugly hack to protect the already damaged switches: six wrap wires, very state of the art suff!
(https://i.imgur.com/nKEbwvi.jpg)
(https://i.imgur.com/wdcDLl9.jpg)
Anyway, some screwing latter only the keycaps remain.
(https://i.imgur.com/5HseVSX.jpg)
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)
(https://i.imgur.com/xmEn44D.jpg)
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.
(https://i.imgur.com/eaJeYMt.jpg)
Oh well, one can't always win.
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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.
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nice!
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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?
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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.