Last weekend I picked up a model 2 Genesis at a yard sale. Got it home and thoroughly cleaned it. I fired up Sonic 2 and there was no video and a bunch of static for sound. I cleaned the cart slot some more and I was able to get video maybe 1 in 4 times but the sound was still static. At this point I noticed that the controller's D-pad did not appear to work and Sonic was constantly inching forward at a very slow pace.
Well I fixed the A/V problems by modding it with composite outputs. (My first time modding something. Go me!

) However I'm still having issues with the controller. I've cleaned the controller ports with q-tips and alcohol as best I can and I checked for broken solder points on the board. I didn't see any broken solder points but I went ahead and added a little solder to each point for the controller ports.
So do you guys think I just have a bad controller or is something else at work here? If it is the controller, any tips on how to fix it? Or should I just take my chances and buy another controller?