I received one of these MacBook Pros with the left wire completely frayed and detached! No display signal on the internal display whatsoever. Is the problem because of this wire not being attached, or is it elsewhere? I get an external display signal without issue. I tried restoring the original OS, same problem. Display System Preferences can’t detect it. The LVDI cable on the other side is fine. One other thing is, all the screws are the same short length holding the bottom case. Someone reassembled this machine and lost the screws!