Unfortunately, after flawless run yesterdayI am still having the MCU knocked out multiple times this afternoon. In regular use, it is. Back in the shop, it's been two hours of beating the thing, rubbing the wires and dragging them on the floor, and the thing runs nicely w/o a glitch. Aaaargh... So a pair of Schotky diodes? (I avoided those since I had none in my spare parts bin).