we just recently got an inverter fault error. it seems to only happen when the spindle is decelerating to a tool change. otherwise it cuts fine has all the power it needs and runs great. there is a break module in there which i suspect is the problem but was hoping someone else could verify before i go spend a pile of money on all the parts. also the problem is fairly intermittent. sometimes it faults on every tool change sometime i can run all afternoon and never have an issue.