How do you find a ground point on a pcb

i was working on building my own arcade stick using a madcatz dreamcast pcb. well i wired up all the points for the buttons directions and start then i had the ground wire attached when i tested it out all my buttons were only giving off movements rather than attacks. so how do i find a place to solder for a ground wire.

It’s the point that’s connected everywhere. There’ll be two points on the part where you solder, one sid eis connected to ground, the other to the proper button on the PCB’s IC. The point that’s common to all is known as “ground”

so its just the common point? damn i feel stupid. :lol: back to the workshop. quick question is there a good way to solder to the weird shaped circles? they look like they are intertwining. guess it would be better to show with pictures.

theres a pad hacking thread