No audio with Scientific Atlanta 8300HD

I am connecting the 8300HD directly to my TV (LG model 42PC3D) using an HDMI cable. Digital and HD channels all work fine. But I am getting no audio on all Comcast standard service channels (channels 2-99).

Comcast has been unable/unwilling to solve this problem. Without running the audio through my receiver, does anyone have any other suggestions?

Reply 1 : No audio with Scientific Atlanta 8300HD

need to into the settings on your remote, press Settings,then "A" for more settings,then scroll down to "audio digital Out",press "select",pick hdmi,hit select again,then press exit.

Reply 2 : No audio with Scientific Atlanta 8300HD

The answer is to open the menu option then more option then select HDMI under the Audio section.
Click on Menu
Click on Menu again
Scroll down to Audio Option
Select HDMI vice the default
Click on Menu
Enjoy the Sound

Reply 3 : No audio with Scientific Atlanta 8300HD

If the audio works on his Digital and HD channels using HDMI, why wouldn't the basic cable chanels have audio?