I have a more interesting "GROSS POSITIONING ERROR A" Problem. I switched ON my machine after more than one year of use .When i was referencing the machine axis it referenced the Z axis normally and when i tried to reference the Y axis it came up with the "GROSS POSITIONING ERROR A"..................................
Now the interesting thing is that after turning ON and OFF the machine many times the " Y axis Reference " line on the CRT became highlighted and the Y axis motor started to rotate in opposite direction i.e. the table started to move away from Y reference and without detecting limits.
Is there any one who faced such a problem ever ???????? for TNC 151
Check the home limi switch and wiring on the Y axis.It sounds like it thinks it`s already on the cam when you try to reference.It then tries to move of the cam,does not see the input changing and keeps going until it faults.