Dolphin Dynamic - one motor only turns counter clockwise

I have a Dolphin Dynamic that worked great for six seasons. This year, the motor on the side that the wire goes into will only run counter clockwise. After about 5 seconds of the motor not turning clockwise (while the other side's motor and the vacuum motor are running fine), the robot shuts off.

I've taken off the side panel, brushes and track, and verified that there's nothing blocking anything. Even with the brushes and track removed, it still only runs in one direction. I can manually turn it with my hand in both directions, and it feels like the same amount of resistance each way.

I hear that replacement motor boxes for these units cost almost as much as a new robot, so I'm thinking it may be shot. I know these robots are notorious for motor failures, but is it typical for a failed motor to only run in one direction? I'm wondering if it maybe something with a logic board and not the motor itself. Has anyone else come across this?

Thanks,
Steve