Samsung UN40D6500 E-Manual page 238

Issues
The picture is good but there is
no sound.
◀
Solutions and Explanations
•
Set the Speaker Select
•
If you are using an external device, check the device's audio output
option. (Ex. You may need to change your cable box's audio option to
HDMI if you have the box connected to your TV using an HDMI cable.)
•
If you are using an external device, check the device's audio output
option (ex. you may need to change your cable box's audio option to
HDMI when you have a HDMI connected to your TV).
•
If you are using a DVI to HDMI cable, a separate audio cable is required.
•
If your TV has a headphone jack, make sure there is nothing plugged
into it.
•
Reboot the connected device by reconnecting the device's power cable.
English
option to TV Speaker in the Sound menu.
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