Jon, on your recommedation I checked out the converter box. There is an AC fuse inside the box, which *looks* intact. I haven't continuity checked it yet, because it means taking the entire box enclosure off--and I suspect that the converter itself just died. On the output side, I reset the 5 or 6 modern style resettable fuses and all of the maybe 8 traditional fuses look good, but nothing doing. I suspect it just isn't producing 12V anymore. However, before I go buy another I guess I'll pull the dang cover off.
Anyways, thanks for the input and story, the latter of which is quite amusing, especially for us coincidentalists.