I I have a Cincinnati Cinturn with the Acramatic 850 sx and I am getting a error code open loop on the spindle I’m able to start the spindle and everything sounds good until I get to 275 rpm then the spindle shuts off and the error comes up it always does it at the same rpm being 275 I’m hoping someone has been through this in the manual it says to change the dump board which I have I own two machines toare identical so I switched boards and also switched the resolver cable can anyone help please