I went back to the Academy, and my old converter was waiting for me. Apparently they take all the converters, extension cords, etc. that are left behind after conferences, and all plug them together: I had to identify mine in a small train wreck of little electrical devices.
So all’s well that ends well. And now I have a backup.
[To the tune of Guns N’ Roses, “Welcome to the Jungle,” from the album “Appetite for Destruction”.]