I can’t seem to get any sound from the optical in. The screen shows it sees the source and is playing it, but no sound. Using a 3.5mm to optical cable, I tried it out of my monitor, with laptop sending sound to the monitor. I tried directly out of my laptop. I tried connecting to my iPhone with an adapter on the end of the cable. Nothing works. Any ideas? I want to be able to play YouTube videos from my laptop (viewing on 35” monitor) while sending sound to my LS50’s.