Hi bigalsmall,
Our suggestion for this kind of situation is to first wait 15 minutes for the minibrute to warm up and then try to set up one of our presets. There are many reasons why it isn't sounding and we want to make sure that it's a defect and not just one of the settings. Let us know if it is still not working. Also, Worlock's link may also help in this situation.
Regards,
Rebecca