Samsung UN40D6500 E-Manual page 237

Issues
Sound Problem
There is no sound or the sound
is too low at maximum volume.
◀
Solutions and Explanations
First, perform the Sound Test to determine if your TV audio is operating
properly.
(go to MENU - Support
If the audio is OK, the sound problem may caused by the source or signal.
•
Please check the volume of the device (Cable/Sat Box, DVD, Blu-ray,
etc) connected to your TV.
English
- Self Diagnosis - Sound Test)
▶