I apologize for the radio silence on this thread. I just want to let you know that this topic is on the top of our priority list and we are working on it diligently to make sure it gets solved.
Here are the updates I have:
We have collected enough failed motors to know that the issue only happens on revision 10 of our motor PCBs. What we have determined is that something is causing a diode to fail on that revision. When that diode fails it brings the power rail down on the entire board and the processor will not boot.
We still don’t understand why some motors fail and others don’t. But we have been able to replicate the failure but only by aggressively back driving an unpowered motor. Obviously that is not how all of these failures are happening. Unfortunately, we have not been able to replicate the issue on a robot. But it could very well be that we are not accurately able to recreate the environment where these failures are happening. Regardless, we are still trying to replicate and are also working on solutions to protect that diode and resolve this issue.
We are currently working through all of our inventory to make sure we do not ship any Rev 10 boards. As soon as we have a solution for this issue we will arrange to rework/replace the remaining rev 10 boards that have already shipped.