MKS Servo42C: jitter or not react to G-codes

Symptom

The steppers jitters at S42C calibration.

Solution

Different stepper manufacturers have different pin outs for internal coils. Please swap the wires with one of the color sequence in the picture.


Symptom

When sending any G-code commands (homing, movements, etc) to S42C, the stepper jitters or just stalls, but S42C calibration still works well.

Solution

The pins at the back side of S42C PCB touch or are too near to the stepper body and create short-circuit. Trim the pins very carefully and don't knock off nearby tiny electronic elements.