19:21
@Criggie it's a ceiling fixture, so in the sense that I reused the metal bracket that fits over the threaded rod attached to the ceiling mount, yes.
but both sockets and their wiring (porcelain with stranded aluminum [looks like aluminum rather than copper] wire) are completely new.
took some pliers and twisted the hot together with the solid black wire coming down from the ceiling and did the same for the neutral, then capped each twist with an appropriate-size wire nut
I'm gonna be heading into the attic this weekend to take a look at the wiring beyond the point it drops through the ceiling.
see if there's some weirdness going on
not sure what I expect to find in the way of explanation there, though. If I don't find anything I'll have to try with some CFLs instead of LEDs