OK, so a quick look at the datasheet suggests that the "disconnected" pin is pin 15, and that it is normally connected to pin 24. This makes sense and these are the two main voltage supply inputs for the motor drive stages. Hence if one of the motor windings was taking too much current, that thin track could fail. Looks a bit thin to me for a motor supply line? Designed to take an amp or two? Hence maybe it simply burned out and effectively disconnected the motor? Worth a repair and a retest?