PS4 Controller dies after tightening case screws.

Disassembled and reassembled my PS4 controller to practice in prep for a modification. Before full reassembly I have full functionality, all buttons, lights and touchpad work. However, after inserting the screws and tightening the top to bottom case, the controller dies. Actually, even before tightening the screws, if I pinch the top and bottom cases together, it dies. I have replaced the ribbon from the mobo to the charge port (in case I had pinched it) and this did not resolve the problem. I'm at a loss and am out of ideas to troubleshoot. Thanks for any help.