Stepper motors are rated for a specific current and sometimes the stepper drivers are not set correctly to match the stepper motor of if you change your motors this may need to be adjusted. The v2 version of the DupI3 have been known to ship with steppers that are rated at a lower current (0.95amps) but the drivers are still set for the other higher current motors (1.2amps). This can cause the stepper motors to overheat or sound loud and harsh. With the extruder motor this can also lead to more heat creep from the heat transferring from the stepper to the cooling block.
- DC Voltmeter
- Small screwdriver (insulated preferred)
- Allen keys (to open the controller and remove the Melzi board)
Identify which stepper motors you have. We have seen -095 (0.95amp), -120 (1.2amp) and (-150 1.5amp). You will need to know the stepper motor current specs to make these adjustments.
For absolute Max current: VREF = Current(A) x 8 * Sense_Resistor (.1ohm RS)
Optimal setting is 90% of Max. VREF = Current(A) x 8 * Sense_Resistor (.1ohm RS) * 0.90
Motors with -0954 should use the Corrected VREF 0.684 = 0.855 amps (90% of 0.95 amp max)
(video by Jim Shank)