I have a mori nv5000 that keeps giving me an inverter alarm during tool change. Not every time though.The machine keeps stopping half way through the tool change cycle as it tries to remove the tool from the spindle. it seems to keep doing it between the same two tools. I have changed out tool holders, thinking maybe somthing was binding, Changed magazine positions, Taken draw bar out cleaned and replaced, Everything mechanically SEEMS to functioning properly. When it generates the alarm I go to custom-atc and easily bring the arm back to home position and restart the program.....What else can I try?.......HELP.