Etymotic MP•9-15 Music•PRO® Electronic - Manual (Page 10)

Troubleshooting
10
Problem: No sound.
What to do:
• Check to see if the battery door is closed
(device turned on).
• Check battery; replace if dead.
• Clean the eartip and the end of the device.
• Check the filter
- remove the filter
- listen for sound to return before replacing the filter
• If sound returns, replace the filter. Once the filter is
removed, discard it and do not reuse.