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geekhack Community => Keyboards => Topic started by: Benaren on Sun, 27 June 2021, 17:16:36

Title: [Need Help] Some keys not working after desoldering switches from Keychron C1
Post by: Benaren on Sun, 27 June 2021, 17:16:36

Hello everyone, first time posting here.

I saw few similar topics so I am asking for help as well.
Got a Keychron C1 keyboard, decided to mod it and since it is not hot-swappable I decided to desolder some of the switches, primarily so I can get the stabilizers out.
After doing so, and soldering them back I noticed that some of the keys are not working, to be more precise both Shift keys, and the Spacebar.

Since I do not have a lot of experience with soldering ofc, I messed something up. I checked the contacts and tried to connect them with tweezers plus a keyboard test software and they register however, not always.

I know from reading online that this can probably be fixed by bridging the connections with a wire, but I am to big of a noob to figure out what and where. Below are attached the pictures of the PCB and the contacts in question. I also went and tried to switch the switches from other places on the PCB and put them in the mentioned keys, to see if the switches are at fault, no the same switches work when soldered to other places.

On the pictures you can see that I went and desoldered other keys, that is because I didn't yet decide if I should remove everything and put a different pcb or just toss everything and keep the parts I can for later use.


So the question is, can this be repaired, and if so how?
if any connections need to be bridged, can someone tell me which ones, as again I am a total noob when it comes to stuff like this.

ND5 - Left Shift - one contact pad got burned off
ND42 - Space
ND83 - Right shift

Title: Re: [Need Help] Some keys not working after desoldering switches from Keychron C1
Post by: suicidal_orange on Sun, 27 June 2021, 17:48:26

Welcome to geekhack, sorry it's not under happier circumstances.  The good news is random dead switches can always be repaired pretty easily :)

The black PCB makes things difficult to see but looks like the diodes are connected to the left pins and then into columns, so for the two shifts touching yellow to pink on the switch next to it should type the shift.  If it does solder a bridge between pink and blue. 
[attach=1]

The space bar pads look OK but there is a bit of damage on the left so it might need reconnecting to the diode - again, touch yellow to pink and if it works solder between pink and blue.  If that doesn't fix it try the same as the shifts (no harm leaving the bridge to the diode)
[attach=2]

Title: Re: [Need Help] Some keys not working after desoldering switches from Keychron C1
Post by: Benaren on Sun, 27 June 2021, 19:44:50

An update on the matter:

Yea Keychron likes them black pcb's  ;D

I tried like described, and the keys work again!!!!!
Bridging the diode did not work, however, bridging with the neighboring switch worked as you described.

I tested all the keys and all of them work once again, keyboard is re-assembled and typing this reply on it right now.
Uploading the picture of the bridges.

Thank you so very much! Not only that you manage to save me 70$ for a new keyboard, you also taught me something new.
I came to this forum searching for help and in a matter of minutes I got my answer that helped me save my keyboard.

Thank you once again, I cannot express it enough!!!!

Title: Re: [Need Help] Some keys not working after desoldering switches from Keychron C1
Post by: suicidal_orange on Mon, 28 June 2021, 02:50:29

Another network cable sacrifices itself to save a keyboard from landfill (https://cdn.geekhack.org/Smileys/solosmileys/laugh.gif)

Glad it works, enjoy your non-rattly stabs :)

Title: Re: [Need Help] Some keys not working after desoldering switches from Keychron C1
Post by: Benaren on Mon, 28 June 2021, 17:00:52

Quote from: suicidal_orange on Mon, 28 June 2021, 02:50:29

Another network cable sacrifices itself to save a keyboard from landfill

Show Image

(https://cdn.geekhack.org/Smileys/solosmileys/laugh.gif)

Glad it works, enjoy your non-rattly stabs :)

hahaha that is so true, the network cable was the only thing I had at hand at that moment, so decided to put it to a good use :D
Thank you, its so much fun to type now that he stabs are not rattle citly :D