Motor control DRI0042

G'day

I recently purchased two DRI0042 controllers for a project.setup as per the application notes from DR Robot. 

One has failed, so I need to find out why.

Total current drawn by the ESP32 and motor/ control circuit is lass than 1.5 amps. I did however mount the pcb to a heatsink and fan. therefore the heatsink would have been ground potential. Would that be a problem.

On the working pcb I have checked the mounting holes and they are common (connected) to each other but isolated from ground.

Do we have a circuit diagram that accurately describes this pcb.

Thanks for your time. Paul