PCB problem for some keys

[thegoodest]

Hello,
First of all, english isn't my mother tongue, so I apologize for the upcoming mistakes.
I recently decided to custom my old steelseries 6gv2 mechanical keyboard. I bought a bunch of switches, and then i started to desolder the old Cherry MX black to solder my brand new switches. After everything was done, I noticed that some keys were not working: F5, Left Control key, and the break key (that I don't often use, but still). I started to think that I did some bad soldering, or even that the switches were not working, so I desoldered, swaped switches, resoldered, and keys still didn't work. So I finally put it on the PCB. I checked on the internet, and some people seem to "bridge" a pin of a not-working key with an other one, by column of by raw (I didn't really understand this part ...), by making contact with a conductive material just like in this video I checked

.
So I tried myself, and yes, something is happening when I make contact with a pin of a not-working key with a nearby pin of another key, but when I make contact while I'm on a keyboard tester, it seems a "random" key is triggered in place of the key I want. For example, when I make contact between my broken-F5 and F6, it seems to trigger the "3" key. For the break key, it triggers the "9" key when I make contact with a Scroll Lock's pin...
Is there any way to find the bridge I have to create to trigger the correct key ? I'm totally new to keyboard modding, and eletronic in general ... so I'm asking for some help.
Best regards,
LM

[suicidal_orange]

It's either keep poking until you find the right place or if it's a friendly design look at the traces and work out the patterns - how hard either is depends how sober the designer was when they made it.  The good news is there isn't a board where single broken keys can't be fixed so no harm done.

If you post a picture with the traces visible in the shine I'll try and work it out, or at least guide where to try poking

[thegoodest]

Thank you for replying.

Here's how it looks. I circled in red the 2 pins that trigger the Ctrl key, but I don't found a logical link with those lines, who seem to be important.
I hope it's shint enoughh for you to help me in some way.

[suicidal_orange]

Nice, it's green so you can see everything and they used the diodes as bridges so it really is everything.  Black or white PCBs have traces that are almost invisible so you need shine to see anything but green is easier all round.

Unfortunately the designer was clearly not sober if shorting those two pins types, ideally they would put all the diodes on the left or right pin to make repairs easier as in the video but not this guy.  Even more impressively all three keys are connected by a trace running half way round the outside of the board!

One jumper between the two yellow dots and you should be good

[thegoodest]

I am surprised with this answer, because, about my Ctrl key, it doesn't do anyting when I connect the two yellow dots. Ctrl key triggers when I make contact between the two red pins I circled.
Just to be sure, I'm making contact using this type of pliers (1st picture, I took if from an eletrical outlet extension), and I'm planning to solder a bridge with this type of wire (2nd picture): is this the way to go ?

[thegoodest]

I just figured out that when I make contact between the red pins, the Ctrl key is like maintained pressed, and when I connect the two yellow pins like you told me, Ctrl triggers only when I press the key, which what I want. So ye I think I'm done with the Ctrl key thanks to you, thanks you !
I've now to find out what are the other missing key on the map 

[thegoodest]

So now I have another problem:
By a certain miracle, all my keys are now working thanks to the bridge I made, and thanks to making contact at some others random points ... I'm not asking to understand all in depth, it works. But I have one more key that doesn't work, and it is my key both symbols "greater than" and "less than". I link to you a picture of what it looks on the PCB.
When I make contact between the two red pins, it's like the key is maintained pressed. So I have hope, but I don't find where I have to make contact to make it trigger only when I actually press the key... and I still don't really understand how I can find it manually without testing every pins of my PCB 

[suicidal_orange]

All the original keys are connected so it's no miracle, it just means you only damaged one pad and only half of it at that - impressive for a beginner with a big board

In the new problem the signal is getting to the switch but doesn't get to the diode when it's pressed, so that's what you need to bridge.  More yellow dots:

[thegoodest]

So I did what is on the picture, and it is not working  maybe something is damaged and they key is lost 

[suicidal_orange]

If the red circles work but the fix doesn't the switch must be broken.  Are the new switches also standard Cherry looking?  You could swap the new stem and spring into one of the old black housings if they are, or the leaf from the old housing into the new depending what's damaged.

[thegoodest]

It appeared that one of the stem of the broken-key's switch was folded, and didn't reach the other side of the PCB, so it wasn't in contact with the rest ! Now I think that everything is in place, working Thank you for all your help !

[suicidal_orange]

That's an easy fix then!  Enjoy your new switches