Originally Posted By trout

(here's the one I think it needs to be)
Video: -----
Audio: HDMI ARC

(here's the recommendation of the HDS manual)
Video: HDMI1
Audio: HDMI1

(I even tried this)
Video: HDMI1
Audio: HDMI ARC


Right. The particular input on the 975 chosen for the ARC function can't be the same as the one being used for audio from the HDS-42AVR (HDMI-1) It has to be another input, Disc, Game, or Video. Which needs to be set as you've shown:

Video: -----
Audio: HDMI ARC
_________________________
Main HT <> 976 <> 7200 <> Ultra-X12 <> sapphire ST2 mkII RF/LF <> sapphire SC center
sapphire ST2 mkII SBR/SBL <> sapphire SS SR/SL <> Verizon/DVR <> Vizio M70Q7 <> Oppo UDP-203 <> Amazon 4k Fire TV