I recently replaced my old plasma tv with a newer smart tv (LG 65” OLED). It is connected to a home theatre with a Yamaha HTR6190 av receiver (pre smart tv variety) via an HDMI cable. The setup went smoothly and cable tv works. Problem is that when I use the tv remote to go to Amazon Prime or Netflix, I get the picture but still get the sound from the cable channel! The store that sold me the tv says that my av receiver doesn’t have HDMI arc and the receiver is too old for the smart tv. Is he right, or am I missing something In the setup? currently all devices (CD changer, DVD player, VCR, and cable box) run through the av receiver. Would running them through the tv be the solution?