Probably there was just a resistor to GND, measure resistance to GND on working one and compare with faulty one. Google about it too. Usually cable gets damaged within a few centimeters from the power brick or near the connector where most of the bending happens. You could crack open the brick, check the wires in the cable. If faulty, cut 10-15 cm of cable and check again. If it measures OK, solder the cable to the PCB and glue the brick back into one piece.