Idle Current Reduction must be disabled PRO board only – install J4 on all the 8-pin headers when setting the voltage.
Re-visit the Vref voltages at the test points where the max current is set for the stepper motors. Compare with the assembly instructions.
You can adjust this setting while the motors are running. If this setting is too low (or zero) the motors will not move reliably or may not move at all.
Use the calculator to the right to determine the voltage that must be present at the small test pad next to the blue trim pot.