Replaced digitizer, touch still not working

Alright so I'm relatively experienced at fixing iDevices, but I'm not sure what to do at this point. I got a 2nd Gen iPod Touch from someone a couple years back for cheap because the digitizer was broken, so I replaced it and it worked fine. So I gave it to my brother, and he broke the screen, and for this past Christmas his gift was a screen replacement. It worked great for about a week, and then the touch wouldn't work. So I was thinking the cable came loose, and I took it apart, and as best I could tell it was just fine. After tinkering with it I noticed that the cable was torn - I think I must have torn it without noticing. So I just bought a new one off of eBay, and that digitizer won't work on this iPod either. So if it isn't the digitizer, and on a quick inspection the connector on the logic board looks fine, what could it be? Any guesses or suggestions?