@ian-tech

As you only have one heater, try putting this in your start gcode

G10 P0 S205 R205
G10 P1 S205 R205 (or whatever temperature you want to print at). That'll set the active and standby temperatures the same so you can instantly switch between tools.

Then make sure that Cura does nothing other than select a tool by putting in a "Tn" command (where "n" will be either 0 or 1). Oh, and make sure that there is nothing in your tool change files - at least for now.

@madeinta1wan said in Overstepping/Understepping Error:

@dc42

T10 is a definite improvement but not exact.

Toshiba6600 doesn't seem to have step pulse width etc or am I missing it?

Is it " Minimum CLK pulse width CLK 2.2 μs"

Thanks

Yes, minimum step-high and step-low times are both 2.2us. Strangely, the datasheet doesn't give the setup and hold times for the direction signal. That probably means they are low. So if you use T2.2 that will set all 4 values to 2.2us, which should work.

Another likely reason for your layer shifts is that your maximum speed (M203), acceleration (M201) or jerk (M566) setting is too high for the axis along which the shift occurs.

Yet another possibility is a bad connection in the wiring for the motor that drives that axis, or a fault in the stepper driver.