In case anyone has this happen, I have a new PreenFM3 and was unable to get the two included wave forms to make audio when chosen.
After reading a bit here and there I tried deleting the bin files in the waveform directory on the SD card, but left the text files. On next power up it generated new bin files and I can now get sound from the waveforms.
Throughly enjoying exploring the synth, pretty new to FM synthesis but enjoying so far.