Salvage a faulty boarded rare K104S

[zazuradia]

Hey guys, i'm just from a flea market and i got myself a couple of old looking keyboard (turns out they're not that old). There's hardly any visible branding on the keyboard itself, just a sticker behind:

Dvck8HUXQAAQ1qg.jpg (488.04 KiB) Viewed 1836 times

Searching for it on the internets i found it's this one:
https://tienda.inusnet.com/en/wired-key ... k104s.html
At first i connected them stright away but they didn't work at all. In fact they both made windows pop a "non recognized hardware" message up, so i decided to look for more info in case they needed a special software or something. It seems not to be the case, so i think the board may be dead. I disassembled one and the board seems to be in good condition. Here are the pics:

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WhatsApp Image 2018-12-28 at 01.08.21.jpeg (287.45 KiB) Viewed 1836 times

Okay, so my questions are:
-Do any of you know what is this keyboard and how can i fix it?
-In case it's a no, does any of you now to use the switch board with a new controller chip or something? I'd really like to salvage these pair (even if card readers don't work anymore).

Thanks in advance. ^__^

[Findecanor]

Does Windows give any more information when you plug it in? A more detailed error message might tell if the keyboard is broken in some way or if it would just require drivers.
I suspect that it could identify as multiple interfaces: keyboard and card reader, and possibly more.

I don't use Windows myself so I don't know what's available. If you were using Linux, I would ask for an output from the "lsusb" program. First "lsusb" to get the Device's ID's, then "lsusb -v -d <ID>" to get how it describes itself. If not in lsusb's list, an excerpt from the output from the program "dmesg" where error code should be found, if any.

Otherwise, you could connect a microcontroller to the flat connectors. I count 12 and 16 leads respectively. 3+1 of these should be for the LEDs though, the last one common. If you don't care about two of the LEDs, you have 24 I/O lines which should be enough for a Teensy 2.0 microcontroller board (with 25 pins), giving you one LED.
But the question is if it would be worth it. Beside the cost of the controller board, there would be a bit of work reverse-engineering the matrix, programming software (called "firmware" when in a microcontroller) and some soldering.

[zazuradia]

Nope, no info at all. I tried a couple of "usbview" kind of applications, but no luck. When i connect them it sounds like a new device is found, but about 20 seconds in the "unrecognized hardware" shows up. Everytime.

I would have no problems rewiring these to a teensy. I do have other pending projects with a teensy and a Model M Terminal, and it's time i ended them. The problem is i have, like, zero idea about creating firmwares for a keyboard or programing for a teensy, but i'm all in about making my own setups, key combos, macros, etc. After all, these are two cherry mx black switched full keyboards at the cost of 6 bucks each. So, any guidance on how should i proceed if i were to use a teensy? Thanks.

[Findecanor]

Too bad. I would start with downloading the source for TMK firmware (or other similar keyboard firmware for the Teensy 2.0). There should be a directory with subdirectories for different devices. Copy a directory for another keyboard and start by modifying the files within.
This does not look like it has diodes, so you would have to enable ghost detection/blocking.

It looks like the matrix is all on one side of the PCB with jumpers on the top side, all of the same length. Reverse-engineering the matrix should be straightforward ... but an amount of work.
I have been using a multimeter in continuity mode, mostly to confirm that the traces I thought led somewhere did indeed lead there.

[zazuradia]

The PCB is a single sided simple one, and i've discovered the leftmost three are the leds. Again, i don't know if this is a standard thing or every single keyboard have their own proprietary connections, and they all look almost the same.
Here's the picture of the entire PCB connections, in case you wanted to see it:

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