Archived from groups: rec.games.video.arcade.collecting (More info?
I have a defender that wouldn't recognize the control panel. I
replaced the interface board and it still didnt' work. I got the board
from Andre at www.arcadesolution.com so I was pretty sure the board
He suggested checking for corrosion on the 20-pin header on the CPU
where that board plugs in, and for a quick fix to try taking some fine
sand paper and clean the pins. Sure enough that took care of it.