First thing, what's the rating on your power adapter. The SNES requires DC 10v 850mA, with a negative tip, which looks like this on the adapter (+)----(o----(-)

Second, have you cleaned the game connector with a q-tip and some rubbing alcohol? Also have you tried multiple games to see if any worked?

Those are the two most common problems with the SNES, if the wire itself is showing a blank black screen as you said then the wire is working perfectly. In my experience third party power supplys tend not to work real well, especially with the SNES for some reason. But if the red light is coming on then, clean the games and see if that fixes the problem.