I have inverter go bad in my vcm-20, there shortly after had offer to fix it by a customer who said it would not be a great expence $ . They got a new inverter for $575. Done a small amout of modification and program change and it ran last night. Ran the program it died on an done very well. It would not do tool change so they change parameter in MD to slow down detent speed and now every thing seems to be OK.