Ok, I dont' know if that was a solution after all. I forgot to report back: I discovered I *could* get music files to play, but not spoken word podcasts. I don't know if it was functioning like that prior to the reset as they it didn't occur to me they might operate differently (since they are all mp3 files).
I recently bought a second one and out of the blue it won't work for EITHER spoken word nor music when connected with an aux cord to speakers, either. Just like the old one, the built-in speakers work fine.