Rudy, thanks for your suggestions on testing the sounds. Yesterday, using the club's power cabinet running Legacy v1.60, I tried resetting/reprogramming the engine with no joy on the sounds. Our show layout was torn down today so the power cabinet used when the engines sounds vanished (and the set absolute speed 0 issue was observed) has gone to the next show venue.
I set up a test bed at home using a 1033, Legacy base v1.52, WiFi, and SER2, and brought the engine in from the cold to test.
Apparently, the process of packing the engine in the box, transporting it, letting it sit in a cold garage, and unpacking at home for testing has restored all sound functions. I started testing in conventional mode - all sound functions worked. Switched to command mode and all sound functions worked.
Could this be a Legacy Base failing issue? The club's LCS WiFi and a Z4000 were replaced during the show, but the base is an early production unit and may need replacement. I have seen other problems such as garbage characters in engine names that may be indicative of failing memory.
John