How long have you had the set for and when did the problem occur?
Also, what is connected to the TV for devices (Cable Box, DVD, Game system, etc.), and do you get NO sound on the TV regardless of which INPUT you select?
First, make sure the Volume is turned up on BOTH the Cable Box AND the TV. Each has its own independent volume control and if one or the other is turned down, then you will have no sound.
Beyond this, please reset the system by following the steps below:
Please shut the TV and cable box down. Unplug the Cable box from AC power for minutes. During this time, disconnect and reconnect the HDMI cable on both ends, making sure it is secure. Then plug the cable box back in, turn on and let it reboot. Once it's rebooted, then turn on the TV and attempt to watch a program.
The sound should be back on at this point.
If you need further assistance, let me know.
Thanks for the reply. This indicates that the audio IC that drives the internal speakers has failed. It is common in these sets as they use very cheap, low powered amplifier IC's that generally heat up and fail. The IC is located on the mainboard, and requires the board be replaced. This type of repair is typically around $225 to replace the Mainboard. If you'd like you can locate a tech at the link below:
If you are comfortable removing the rear panel of the TV, and removing a few screws and unplugging a wire harness, then you can fix the problem yourserlf and save quite a bit of money.