I have been using my Panasonic SA BT300 home theater (HT) to play audio from my TV via an optical digital cable. It has worked great for 5 or more years. However, I just purchased a new Hisense TV from BestBuy to replace my older LG TV. The new TV is 4K, smart, etc. but I cannot get the digital audio out on the new TV to work with my old HT. I tried another TV to be sure the HT and cable are still good and everything checked out. I also took the TV back to BestBuy because I thought the digital audio out on the new TV was bad. However, the new TV digital audio worked fine with a soundbar they have in the store...so the TV is good. I have tried changing the settings on the TV to RAW and PCM...I have the correct DV1 Optimal port on the HT selected. Also...I tried using an adapter to connect the head phone jack on the TV to the RCA jacks on the HT and that didn't work either. I have updated the firmware on the HT and the TV updated its software as soon as I turned it on. Can my older HT just not be compatible with the new TV via the Digital audio optical cable?