SNES turns on but only displays black screen.

A while back I bought a broken SNES thinking I might be able to fix it. It wasn't that expensive so I figured it would be fine if it doesn't work. I'm tired of looking at it and it being nothing more than an expensive paperweight, so I finally went here to ask for help. When I plug it in and turn it on with starfox (untested since I don't have another SNES) in it, my tv goes from a no signal screen to a black screen so it clearly knows my SNES is there. I opened it up and can't see any obviously broken parts or obvious corrosion. I think I'm using a knockoff power cable but the AV seems legit so maybe the power cable is bad? I can borrow a multimeter or something to test it. I don't think my tv is a CRT but I'm using the AV ports in the actual tv with no adapter so I don't think that's an issue but I can possibly test it with my friend's CRT. Can anyone tell me what might be wrong? I'll try to give any information you need but I don't really want to purchase any more games since it might end up not working and the games are too expensive that.