HELP FIXING PCB CONNECTIOIN

[Buraiha]

TLDR

After soldering new switches (Tangerine 63g) onto my Whitefox keyboard, all keys worked except the space bar [RED BOX]. I replaced the switch, tested it on multiple computers, and I am quite sure the issue resides with the PCB.

I understand that keys are organized in a nxn grid matrix configuration to a very basic degree.

The Whitefox's schematic can be referenced here: https://github.com/kiibohd/pcb/blob/master/WhiteFox/WhiteFox.pdf

I was wondering if anyone in the community has insight on resolving this issue. Is it perhaps that the solder point has some "residue" [underlined in YELLOW] which is preventing the connection from forming? I don't see why this would be the issue as I assume the connections are INSIDE the PCB, not on the surface. Would wiping away the residue help with this issue, and if so, what's the best way to do so?

I used a paper clip and found that if i connect the 2 points [GREEN line], then by pressing the space bar switch, it registers the space bar. I could also solder a wire connection between the 2 points and call it a day, but if so, I was also wondering if anyone has any idea the best way to go about it.

I appreciate everyone's help on the matter as I am not the most technical person when it comes to these things!

[suicidal_orange]

You can see the telltale sign of a damaged pad (the brown burn mark) but no problem as your fix is correct.

Find some insulated wire (it can't be too thin so any wire will do) bend one exposed end through the empty hole and cut so it sits close to the PCB.  Solder the switch end then the hole end (the order is important if it's stiff single core wire to avoid pulling up the empty pad) and it will be good as new, but with better switches

[yui]

when the peoples do all the work themselves but still ask for help just in case
Nice job, oh and that residue is flux, it actually is here to help to get better connection, although some fluxes are conductive and when not cleaned can give you all sorts of trouble although not what you have here.

[Buraiha]

Thank you for everyone's input!

I've bought some copper wire which I will cut, and strip the plastic ends off. Then I will solder that as the connection between the points.

[Buraiha]

Although I'm a bit confused how the flux / "burn" portion could cause a disruption in the circuit as the wire connection in INSIDE the PCB and not on the surface from my understanding.

[suicidal_orange]

It's hard to see but there are raised lines running all over the top of the PCB under the white coating which are the traces (wires) - if you look in your picture you can see the start of one attached to the circle around the other pin of the space switch heading to the bottom of D65.  A little too much heat (enough to turn the flux 'puddles' from nearly clear to brown) and the pad lifts slightly breaking the trace.

You can get multi layer PCBs with traces safely hidden in the middle (though they also have traces on the surface) but keyboards aren't complicated enough so all the traces are on the front and back.

[Buraiha]

Quick Update: Everything is working smoothly!

[suicidal_orange]

Great, enjoy those beautiful new switches