If you connect an optical cable to the OPTICAL INPUT, you will need to assign a source (AUX, TV, VCR or TAPE) to the input.
To assign the optical input, follow these steps:
Assigning the optical input
Turn the TV on and select the correct TV input
on the remote, press settings
press tune down to highlight "system setup" and press enter to confirm
press tune down to highlight "optical source"
press seek forward to select the desired input (aux, vcr, tape or tv)
On the remote, press the source button (AUX, VCR, TAPE or TV) that you have selected in the menu. You should now hear audio from your connected source