KB-5191 Diagnosis

ManOfBigProportions

21 Oct 2021, 18:32

I got this keyboard from ebay in working condition, but because I didnt have a proper adapter for the din5 interface I made my own really janky din5 to ps2 adapter and it worked fine. Because I wasn't planning to keep using my abomination of an adapter I ordered one through aliexpress. Last night I tried the adapter, and the keyboard did not light up. Confused I began checking the cable with a multimeter, and to my surprise the vcc and gnd were wired backwards and the cable only had 3 wires. Realizing what I just have done, I mutilated the cable and wired up my own adapter to see if I killed it. Now the keyboard lights up all the status leds at once (scroll lock led was dead when I got it) and it doesn't register keypresses. This is my first vintage keyboard, and while not great I still liked it. I kinda overpaid for it too. Where do I start? Is the microcontroller dead? How do I check?
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UnscrambledEggs

21 Oct 2021, 19:15

As a last resort, perhaps you have clock and data reversed? The locklights prolly signify a dead controller ):

ManOfBigProportions

21 Oct 2021, 19:20

I checked my connections 15 times over, i also re-soldered the wires. It's most likely dead. If i were to find a replacement controller, would just replacing it work, or will i have to program it somehow?

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UnscrambledEggs

21 Oct 2021, 20:31

It's most likely a custom chip made for Chicony; if you were to find a replacement, it'd prolly have to be from another board of the same model. Otherwise, you could map the matrix and solder in a QMK controller like a Teensy or something like a Pi Pico with KMK.

ManOfBigProportions

21 Oct 2021, 20:49

Yeah I was thinking about using a modern MCU, the problem is that I have no idea how to map out the matrix. Can I just use the existing solder pads from the Intel MCU and just solder the teensy or the pico on that? I mean the pico and the old intel controller are both 40 pin.

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Palatino

21 Oct 2021, 21:08

Just a thought, may not work but may save time + expense: whenever I’ve had a board not respond and all the lock lights come on, it’s because I’ve unplugged it from a computer in a way it didn’t like: I either removed the keyboard cable from my 5 pin adapter, or the 5 pin adapter from the PS2 to USB converter, or the PS2 to USB converter from the computer - I can’t remember which one of those it didn’t like. I can always fix it by unplugging everything and reattaching, sometimes needing to open a new document or restart the computer too (once I think I cleared it by reconnecting it to a different computer). Worth a shot maybe before you start resoldering - though perhaps you’ve tried all this already.

ManOfBigProportions

21 Oct 2021, 21:16

Since I use a passive din5 to ps/2 adapter, I know that ps/2 is not hot pluggable, so i always shut down my PC when I plug in my keyboard. Before the board stopped working, when I shut off the PC only the on line led was on, now all the lock lights are staying on even if the PC is off. The moment I start the PC until the moment I completely cut power on the PSU, the lock lights never turn off. Also forgot to mention that the AT/XT switch doesn't change anything.

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UnscrambledEggs

21 Oct 2021, 21:53

ManOfBigProportions wrote:
21 Oct 2021, 20:49
Yeah I was thinking about using a modern MCU, the problem is that I have no idea how to map out the matrix. Can I just use the existing solder pads from the Intel MCU and just solder the teensy or the pico on that? I mean the pico and the old intel controller are both 40 pin.
They may have the same amount of pins, but they aren't pinout compatible. I believe there are guides online to get you on your way; sorry I can't be of more help, it's hard to explain how to map a matrix with my small brain :P

ManOfBigProportions

21 Oct 2021, 22:20

UnscrambledEggs wrote:
21 Oct 2021, 21:53
ManOfBigProportions wrote:
21 Oct 2021, 20:49
Yeah I was thinking about using a modern MCU, the problem is that I have no idea how to map out the matrix. Can I just use the existing solder pads from the Intel MCU and just solder the teensy or the pico on that? I mean the pico and the old intel controller are both 40 pin.
They may have the same amount of pins, but they aren't pinout compatible. I believe there are guides online to get you on your way; sorry I can't be of more help, it's hard to explain how to map a matrix with my small brain :P
You have helped me plenty. Before I posted here I had no idea where to even start. Thank you.

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Sheepless

21 Oct 2021, 22:31

ManOfBigProportions wrote:
21 Oct 2021, 20:49
Yeah I was thinking about using a modern MCU, the problem is that I have no idea how to map out the matrix. Can I just use the existing solder pads from the Intel MCU and just solder the teensy or the pico on that? I mean the pico and the old intel controller are both 40 pin.
LOL. My car and a Ferrari both have 4 wheels, but there the similarity ends.

ManOfBigProportions

21 Oct 2021, 23:05

Sheepless wrote:
21 Oct 2021, 22:31
ManOfBigProportions wrote:
21 Oct 2021, 20:49
Yeah I was thinking about using a modern MCU, the problem is that I have no idea how to map out the matrix. Can I just use the existing solder pads from the Intel MCU and just solder the teensy or the pico on that? I mean the pico and the old intel controller are both 40 pin.
LOL. My car and a Ferrari both have 4 wheels, but there the similarity ends.
Yeah I phrased that sentence wrong lol. I know they are not pin for pin compatible, what I meant to say is that I can probably re-use the solder pads of the old controller for the new one.

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hellothere

23 Oct 2021, 20:01

It might be worth a shot to wire up a Soarer's Converter. Low cost, relatively easy to do.

I've attempted replacing the controller in a KB and mapping out the matrix. I eventually got to the point where I decided that doing a custom hand wiring job, sans PCB, looked easier. I then shelved the project. I've got a lot of other easier to repair keyboards.

SK-8K

23 Oct 2021, 21:27

That PCB looks very easy to copy. I could design a replacement PCB for this model of keyboard if someone lends me a 5191.

ManOfBigProportions

25 Oct 2021, 04:59

SK-8K wrote:
23 Oct 2021, 21:27
That PCB looks very easy to copy. I could design a replacement PCB for this model of keyboard if someone lends me a 5191.
I would give you mine, but it's impossible for me to ship stuff anywhere.

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