I have a kobelco sk200lc mark 4 and I'm having trouble with the step motor and not sure how to diagnosis the issue. This excavator sat for 10 yrs and wasn't used. I changed oil and cleaned up some electrical connections and it's been working great the last couple hundred hrs. But today I went to move it and it won't rev up and gives me a s/m fail or a s/m off warning once in a while. Plus the closest kobelco dealer and mechanic are 200+ miles away, and they aren't very helpful getting parts let alone service from what I've found since I've gotten this. Thanks.
Try checking your electrical connections from the controller to the Step motor and the resistance of the step motor coils and its limit switch. To calibrate the step motor requires a simple switch and harness made up and connected into the controllers 1p connector. Then a sequence is initiated which involves setting the min and max throttle positions of the step motor governor linkage arm before a series of steps is then carried out by the controller. This calibration procedure was always a bit of headache to carry out in my experience.
Thanks I'll do some tests