3DS Outer Cameras Cause Sytem Error

Hey guys, so i recently had finished Repairing my Little sisters 3ds that Broke a while back. it had extensive damage, and a few pieces went missing(this was my fault due to poor storage) . i had to replace everything on the upper half of the system after the hinge broke and the ribbons sheered,. Cameras, Screen, Speakers, the antenna was salvageable tho. other then that the shell, bottom screen, and touch was replaced and i replaced the wifi board. ( i lost that guy by accident). now it powers up and works perfectly, BUT when i press R+L or go into the camera settings i wind up with an Error saying:"an error has occurred. hold down the Power Button to turn the Power". i load up Face Raiders, the App and i get black screens for both sides. i want to assume i diddnt plug in the cameras properly but i dont think the system wouldnt turn on if i did. does anyone have any ideas to what could be causing this?