FM don't work

FM worked but Quit . Station is diplayed but no sound.Music Mode still works

The first thing you can do is make sure you have the most up-to-date firmware.  Download and install the Sansa Firmware Updater and it will run when the player is connected to your computer.  If there is a firmware update available it will notify you.

Also, when attempting to listen to the FM hit the Play button to make sure you don’t accidentally have the mute on.