Dynex offers a line of LCD TVs that range from 32 inches to 46 inches in size. If you're not hearing audio from your Dynex LCD, there are a variety of reasons this could be happening, such as an accidental press of the "Mute" button or poor cable connections. Check the audio settings and connections to isolate the problem, and see if you can solve it on your own before taking the TV to a professional repair person or sending it back to the manufacturer.
Press the "Mute" button on the remote control that came with the TV or press the "Mute" button on the TV. Continue pressing the button until the mute icon that appears in the upper left corner of the TV screen and looks like a speaker that no longer has a line through it.
Change the channel on the TV if you're watching a program that's being pulled in over the air to see if the problem is unique to the channel you're watching, which implies the problem is with that specific channel and not the TV. If all of the channels are experiencing the problem, there's a problem with the TV.
Picture but No Audio
Press the "MTS/SAP" button on the remote control until either "Mono" or "Stereo" appears in the upper left-hand corner of the TV screen. If your audio mode is set to SAP, you'll hear a channel's secondary audio. If the channel you're viewing doesn't have secondary audio, you'll hear nothing.
If you aren't hearing audio from an external device, check the audio cables connecting the source device to the TV. Push the connectors on the audio cables firmly into the matching-colored jacks on both the source device and the TV. If the connectors aren't firmly pushed in and making a connection, you won't be able to hear any audio.