I checked the volume from the WinCE control panel, ran that through your
Binatone Toolbox (thanks for that), checked everything I could, reset the deice to defaults through the Binatone shell, no joy, both the original sat nav program and iGO Primo have no sound.
The deice was bought through ebay, so I don't know if anything's been done to it. Barring a hardware fault with the speaker, it could be something in the wince registry or a file missing, a codec or something, don't know, I'm not sure what do I need to check there. And being that the Windows Mobile Device Center in Windows 7 does not detect the device when connected on USB, I thought a reflash might be in order.