Unscrew the palm rest and locate the grounding wire, that is leading from the non functional tower.
Disconnect the grounding wire from the grounding block for that tower and re-connect it again, making sure the wire is making a clean contact and no insulation is stuck in the screw-in clamp. You can plug in your usb again while the palmrest is open to test the keys, just make sure you are not touching any of the wires or board while your Azeron is plugged in.