Quoted from fodorfolde:
Thanks CNKay for the learning. Seriously!
I located the PDBD for the non-working pop bumper, unplugged it and plugged in the connection from one of the working pop bumpers. Worked. So that isolates the problem to the actual pop bumper (logic would suggest).
I resoldered the connections and still nothing. I suppose I will next remove two of the pop bumpers.... Resolder one of the working ones into the position where there are issues and check if it works. If it does, I'll look over the non-working pop bumper and post again. If my thinking is flawed though, please correct me.
This is actually fun... especially with all the help.
I have a MGoW as well and experienced the same issue but when I moved the driver board to another bumper that one didn't fire. My problem ended up being the cold solder joints (as suggested in another post).
I didn't watch the video so I apologize if any of this is covered there. Check the switch at the bumper and make sure it is closing correctly when the ball hits. One other thing to check is that the female connector is also making a connection with the pop bumper driver board as well as a solid connection back at the boards back behind the back glass (if they originate there, I'm pretty sure they do but didn't have to go this far).
It wouldn't hurt to reflow solder on those pop bumper driver boards anyway. I fixed one, put it back in the machine and it worked and another one had failed for precisely the same reason within just a few minutes after reinstalling. I ended up reflowing them all and doing the system 80 pop bumper upgrades just for the peace of mind that it was fixed.