I came across a battery charger for some heavy duty animal shears. The thing had a nice heft to it. Inside there were a couple relays, a barrel jack, some big caps and a bunch of ICs which I haven't looked up the part numbers for.
After opening it up it was apparent the failure was a diode that somehow cracked in half. There were magic smoke stains on the underside and everything.
Here it is, as always click the pictures for higher resolution and additional pictures:
Circuit board bottom, notice smoke residue near the top center: