I have a 2011 Mori Seiki NTX1000S that is getting the error SP9031 S2 SSPA : 31 MOTOR LOCK OR DISCONNECT DETECTOR. The tool spindle isn't under load, the problem is that the tool spindle doesn't even start up about 5 percent of the time, it just goes in reverse about a quarter rotation and then gets the error. Now it won't even index the tool spindle for a tool change, the spindle just stutters and moves a bit. I had Fanuc out to change the spindle amp and the sensor in the spindle, but nothing helped. DMG Mori does not know what the problem is.The machine has been down for three weeks now, so it's really frustrating. I am hoping that someone on this forum has some idea on what the problem is. Thank you, I really appreciate any help.