I have the Roku Ultra 4640.
I am using a AT&T UVERSE cable box with my Samsung Smart TV and an Onkyo Stereo. I get a clear picture when I turn on Roku but I don't get sound from the program. I only receive the TV sound from the cable station which does not correspond to the ROKU program. I have switched the HDMI Cables. I tried doing the same with my Amazon Firestick and have the same exact problem. I am checking the source on both my TV and Stereo so that is not a problem because I get a clear picture.
I tried turning the power off and on, switching HDMI cables, using different HDMI ports on my TV to no avail. Please send me a schematic diagram of how I should be connecting all cables with my AT&T UVERSE cable box, my surround sound Stereo and my Samsung Smart TV.