My star tracker died 40 minutes into a clear night in Joshua Tree

Drove out to Joshua Tree a couple Saturdays back with the whole setup packed in the trunk, and right after I got polar aligned the mount just stopped tracking with no error at all. I swapped the USB cable and tried a fresh battery pack, but the motor would only move in one direction, so I ended up shooting 8 second frames on a tripod and stacking them later. Back in the day I just ran a barndoor tracker I built in the garage and it never gave me a bit of trouble. Cutting my exposure time that short made me miss the old simple nights, and the Milky Way core came out grainy no matter how hard I pushed the stack. Has anyone had a mount motor die like that and fixed it without sending it in for service?