Hi, thank you for your note.  This is typically caused by one of two issues: 1. the volume knob is turned all the way down on the main controller, or 2. the power sources are providing insufficient power.  See this knowledge base article and let us know if this helps:

https://brickstuff.zendesk.com/hc/en-us/articles/360015396691-Clicking-Sounds-or-No-Sounds-from-Millennium-Falcon

Thank you.