HTL-HD losing audio on cable TV input

After purchasing an H20 D* receiver for the main TV room, I relegated my older HTL-HD to the bedroom. Have a similar set-up in there utilizing all three coax inputs: OTA antenna, AT9 D* antenna, and Charter Cable TV. Picture and on-screen guide works fine for all three options. However, I am only getting audio for the D* channels (both SD and HD) and OTA channels. No audio for the cable TV channels...at least not consistently. Had it initially after hook-up....days later had none....next day lost all cable TV audio again. Using same optical audio cable arrangement from HTL-HD to A/V receiver.

Have talked with D* tech folks, done the reboots, etc. No luck in locking-in on the Cable TV audio.

Thanks for any advice.