Having an issue with a new Roku 5 Series 55" and connecting to my Vizio sound bar using an optical cable. I've called Visio and TCL and spent way too much time over the last day trying to sort this out. The Vizio soundbar does not have an HDMI cable, so I'm using the optical cable connection from the soundbar directly to the TV. I've confirmed that the soundbar works (it connects to Bluetooth) and is on the correct input setting for optical cable (the 7/8th lights on the side light panel). There has to be something with the TCL settings because when I disable the TV speakers and follow the suggestions I've found so far on enabling PCM-Stereo, I get no sound. I've tried all the different settings to no avail. I'm at a loss and firmly believe it should not be this difficult to connect an audio source. FYI - No subwoofer or anything like that. A simple soundbar.
Have you tested connecting the soundbar to a different model of TV to see if it works correctly? Have you also tried replacing the optical cable in use? Optical cables can be fragile, and if bent can become non-functional.
Please try both of those options and let us know if you are still experiencing an issue.