[MT Stringer]

The spindle runs fine with MDI, and VFD wiring also looks fine (did not rewire). It only happens and re-occurs with one particular g-code file but I don't see anything wrong with it, no M5 or other insertions. I think this file is somehow corrupt. I now always use Vector Validator to make sure geometry is right. Don't know if incomplete geometry can cause this kind of problem.

Just maybe the vectors contain a boat load of nodes that are causing the slow down. Check your file and see if some of them can be removed by using the "smooth" tool on the vector where the nodes are thick.