Originally Posted by 2Doggs
Was the solder bad on that centre motor lead? Looks like heat there and on one side of the pcb.
That's just how lead free solder looks. It's why when they went over to lead free solder they had to lower the standards for acceptable solder joints. They just couldn't meet the quality standards that had been designed around tin/lead solder with the lead free stuff.
There is a reason why lead free solder is banned in aerospace applications. It's just not as good and they don't want planes falling out of the sky because of it. It also might lead to the public asking uncomfortable questions about lead free solder's long term reliability elsewhere.