Weird. I put in an SD card in a reader (as the built in one has given up the ghost) to save a file to move it between computers, and as I copied the file, I thought I heard a noise. (She thought she heard a noise - Ha Ha! Sorry - the internal playlist ran to the end of the Pirates.) I wasn't sure, so listened carefully as I did the safely remove thing, and Lo, the proper beeps were heard! So I tested it on the Digitrad and a MIDI file. Sounds are back. And it hasn't been off since last post, either.
No explanation at all.
Penny