I've fixed a lot of Z series displays, it seems they're very hit and miss or, they're incredibly fragile.
Did you try and test the LCD before installing? I think bending the flex cables like so can do damage, I don't bother doing it anymore and make sure the LCD is in the intended position (without frame adhesive) and then test it when it's installed into the frame.
Did you say you tried the old LCD and it's showing the same signs as the new LCD?