I am trying to switch my 3g motherboard or logic board w.e with the iphone 3gs. I did everything swaped digitalizer screen and the sound board thing at the bottom which connects the itunes cable and speaker. Swapped those, I broke the screen from the 3gs so I need to buy a new one. But then when I put back together the 3gs it turns on bc I turn the silent off and on and the phone vibrates but I get nothing on the screen just black.. I connected the cables is there something I'm doing wrong. Also I switched the cameras also. Don't ask why I'm doing this.