Stan, I'm guessing the ones in the middle with the smutz on them are the failure items. I notice in the other photos the discoloration of the bottom board where something blew. The one diode in there seems to have different banding, so it's likely to be a different type. Perhaps measuring some from boards that don't show failures will yield a guess as to diode type? On a diode test on your meter, a Schottky should show a significantly different voltage drop.