It’s most likely that it’s related to the original manufacturing. These will be machine wave-soldered, not hand soldered, and having quality vary across the board isn’t impossible if the setup/operators were less than ideal.
Perhaps. It still seems odd to me that this board was mounted vertically inline with the heating element and the bad parts I identified line up with that, before I knew that was the case:
It’s most likely that it’s related to the original manufacturing. These will be machine wave-soldered, not hand soldered, and having quality vary across the board isn’t impossible if the setup/operators were less than ideal.
Perhaps. It still seems odd to me that this board was mounted vertically inline with the heating element and the bad parts I identified line up with that, before I knew that was the case: