Chosen Solution
My Sega Genesis 2 second controller port is not working at all, I’ve tried desoldering and soldering the port a couple times. I’ve also reflowed everything on the back of the board and checked continuity from where the controller plugs in to the resisters just in front of where the pins solder to the motherboard. The weird part is in sonic 2 and 3 it actually does kinda work but then gets stuck going left. What can I do that I haven’t already?
It’s possible you may have a bent or missing pin. Look inside of the controller slot and if a pin is bet you should be able to bend it back, however if it’s missing I would try to find a new connector and solder it on.
