There is no audio when viewing cable channels.

Verify that the MUTE button on the set-top or the remote control has not been pressed. Press MUTE on the remote control to restore sound.

If the set-top audio output is connected to the TV, verify that the Mute button on the TV has not been pressed.

If the set-top audio output is connected to a home theater receiver, verify that the receiver is set to the appropriate input source and the Mute button on the receiver has not been pressed.

Verify that you have the correct cables for the audio ports.

Verify that the audio cables are firmly connected between the set-top and the TV, VCR, or home theater receiver.

There is no audio from the center and/or surround speakers of a home theater receiver connected to the set-top.

Not all Dolby Digital programs feature full 5.1 surround sound. In some cases, the programs may only contain left and right stereo audio.

Verify that the S/PDIF cable (coaxial or optical) is firmly connected to the set-top and the home theater receiver.

Verify that the home theater receiver is set to a surround sound audio mode (Dolby Digital, Dolby Pro Logic®, or Dolby Pro Logic II.

Verify that the receiver is properly configured to work with all connected speakers.

There is a humming noise.

The DVR set-top provides an internal fan to cool the integrated hard drive. During normal operation, the fan emits a low humming noise, similar to a personal computer. The volume varies occasionally when the fan speed adjusts to changes in the temperature around the set-top. The hard drive remains ON, even when the set-top is turned OFF.