Hello everybody,
I’m operating a UR5/CB3 cobot and i’m experiencing these issues while trying to complete the initilization procedure and startup the axis.
When I press “ON” on the initilization screen, the cobot starts up all the axis (I feel the motors starting up) but after, when I press “Start” to enable movements, it starts moving slightly the axis (to make the initialization procedure) and after a while it fails and returns the errors C75A1 and C215A0.
I report the two errors toghether because i’m suspicious that the C215A0 error could be the cause of the whole failure.
What could be the root cause? How can I fix this issue? Is there the possibility to properly reassociate the cobot to the controller.
Thank you.
I had twice a similar issue. Then when starting the robot manually, I would move every joint individually. And in both cases it turned out to be a bad joint that had to be replaced.
So I opened a case in myUR, reported the findings and what joint nr it was, and they replaced them.
There have been some CB3 robots that have suffered from a slight fault during production. The pins of one of the connectors on the PCB within the joints have had coating added to them, which in some cases was not removed properly before assembly (before 2019).
A possible solution is to remove the connectors and connect them again. That would definitely be my first course of action. 
You can read more here: If joint encoder errors C75xxxx occur, try these suggested steps for each joint in this guide.