How can I check the ballast resistors ? Are they inside the KSP ?
I'd hate to open these babies...
Ballast resistors are located in the back of the controller, inside of the controller they are marked with R1 in R2. They each have 22ohms and they are connected in parallel. Also i would try with reload files, if you still didn't tried it.
Because errors come and go, so there is no option but to check and rule things out one by one, like panic mode advised, and really check things by measuring etc. and for example one could have 40kg mounted on the KR210 but those 40kg could be mounted also 5m away, not directly on the flange, also one could have 40kg mounted on the flange and $LOAD values way off (for example for M 230 kilos entered, center of gravity way off, inertia) and the robot would tried to work with those values regardless if there is only 40kg mounted.