Console not booting after refurbishment?

I have recently bought a defective 3DS XL from eBay. Someone had stood on it and the top and bottom screens were separate (all ribbons had been torn too). I have replaced the top screen, speaker/3D slider ribbon assembly, hinge, outer shell, just about everything except the bottom screen and motherboard. I have reassembled the console and the screens turn on, they pop and and go off. I know there have been reported issues with this, however when I try turning the console on with everything connected just without the shell, the screen backlights come on, as does the blue power light, and does nothing more - doesn't turn off, but doesn't turn on either. Some things to point out: I am operating the unit without a camera, and the case is slightly defective - the hinge doesn't turn when I close the console lid. I have set the hinge to open and still no joy. I believe I am putting the ribbons in the correct way, but maybe not far enough? They only go in a little way and budge no further (I am referring to the lower screen digitizer ribbon and the two small ribbons coming out of the top screen which connect to the speakers.) Is it possible to put the hinge in the wrong way too? Besides that I am clueless as to what is wrong...