Optik - no sound

[wireless]

Cisco PVR box has been intermittently dropping sound, but a channel change or reboot would always fix it. The audio is now AWOL for good, it seems. My set up is Optik to XBox to receiver, all via HDMI. Tried optical, tried swapping HDMI cables - same result. Checked output/input settings, tried stereo - still no dice. Other boxes in the house are fine. Seems like a call to Telus is in order, but before I do, anything I could be missing?

More... (https://forum.telus.com/t5/Internet-TV-Home-Phone/Optik-no-sound/m-p/71159#M11360)