Forgot to post this last week:
My motherboard is toast, and it took me nearly the whole week to deal with it.
Discovery had a quick response once it was in their shop, and the verdict is that it's a warranty-replacement motherboard. Their best guess is 3 weeks for me to get it back.
In order to get back to work I pulled the drives from my dead box and rebuilt another machine.
Update: Got an update on Oct. 29. Apparently the new board is at the borderr and I should have the machine back Wednesday-ish.