if the cable is broke u get similar matters, i experienced it myself, the warranty was void so i desoldered the cable, took a piece out and resoldered the new ends, runs for a good 4 years again, before about 6, my 518 is about 10yo, just sad it wont be enaught for 4k resolution.
the cable most likely broke near to the mouse.
btw., r u getting the usb detatch sound?