I need iphone 3gs expert please?

I'm having my Wi-Fi issue after i dissambled my iphone 3gs. I cleaned camera because there was dust… And assembled again without problem but then i realized i couldnt see available networks that i used to connect before. So i dissambled to see if n6 was in its place i did twice but it still has very weak signal i'm using it right now but it only sees Wi-Fi in about 2 meters pla help if you know

Go to apple