Thanks for the great info!

I've been putting off posting back until I can get some pictures.
Unfortunately, my MK2 board does not have that diode (at least in the same place.) Evidently the rearranged some of that stuff between the MK2 and the MK2a.

The only pic I could find that looks like mine is this lower-res image I cribbed from mrmunsell's fuse replacement guide.



I'm going to snap some higher res pics soon and hopefully figure out what could possibly be the issue.

Ideally, if PCA could comment on what would be the likely suspect...

Stay tuned...