I don't have this machine so only guessing what spins the head, but if it spins on a servo, what you are describing is caused by a faulty servo (that is if it uses one). Not being able to find the center point and spinning around are common servo issues in the R/C world and are usually caused by failing gears in the head of the servo. It is an easy fix if that is the case. You could then just replace it. Again, only with the assumption of a servo controlling the head.