do you have a multimeter?
does it have a continuity tester?
usually indicated by a music note or similar.
this will help you find where the break is without soldering anything until you find the break.
(do a google search for "multimeter with continuity")
what i was saying was
- any of the pads within the green line should all be the same and should ring/sound when you test between any pads within the green line.
- could jump between two pads in the green outline say if you lifted a pad or broke a trace when removing a switch
- any of the pads within the pink/purple line should all be the same and should ring/sound when you test between any pads within the pink/purple line.
- could jump between two pads in the pink/purple outline say if you lifted a pad or broke a trace when removing a switch
- any of the pads within the redline should all be the same and should ring/sound when you test between any pads within the red line.
- could jump between two pads in the red outline say if the column trace is broken.
if you didn't lift a pad, and the break is further away from the switch legs, it might be within the red outline (column) or it might be and is more probable that it's in the row trace, since it's the last switch in the row. i can't see the row traces because they are actually on the other side of the pcb and i can't see the switches to the left because they are not included in the photos you provided. i tried to look at other pics online but i didn't find one with the date that's on your board or they were white pcbs and hard to see the traces.
can i see a pic of the whole pcb? this same side is fine (backside, not switch side)
- in the pics you sent, i can't get an orientation. if it's in the bottom of the left side or close to the top of the right half....
did you change the (reflash) firmware/keymap when you changed switches?
was it working before the switches were changed?