But when I went down to swap out a load of laundry, I heard the dehumidifier kick into life behind me, but it didn't sound like the fan was running, just the compressor. About a minute later, it kicked off. I checked the top, which was *really* hot.
Aha! Time to unplug this beastie. It seems that a bearing had gone on the fan on this rather elderly unit. Almost certainly elderly enough that it was time to replace rather than even consider repairing.
A bit of research found a suitable dehumidifier available at our nearby Home Depot that was even on sale right now. So I placed the online order, picked it up later this afternoon, and it is now installed in the basement and humming along, which is good, because we really need to keep that humidity down to reasonable levels.
Now, I just have to check the local regulations on about how to dispose of the old dehumidifier...