I have a Panasonic DP-UB820 connected to a Yamaha RX-V6A which in turn feeds a Samsung S90C.

This set up is quite new. Yesterday I bought some new HDMI cables to tidy up the installation. Specifically, Cruxtec 1m HDMI 2.1 Cable - 48Gbps , Full Ultra HD ( 8K/60Hz & 4K/120Hz ) and J5create HDMI 2.1 Certified 2M Premium UltraHD 8K 60Hz 4K 120hz HDMI Cable.  I had been using some longer lower quality HDMI cables when I set it up initially.

The DP-UB820 is connected from its HDMI Video Out (Video/Audio) port to the HDMI 1 port on the RX-V6A. The RX-V6A is connected via the HDMI Out (eARC/ARC) port to the HDMI in eARC port on the S90C.

Up until yesterday when I played a DVD on the DP-UB820 the audio played through the stereo speakers as would be expected. Since I put the new cables in I no longer get any audio from either the stereo speakers or the TV speakers when I play a DVD.

Audio works properly when watching the TV. 

If I connect an HDMI cable between the Audio Out port of the DP-UB820 and HDMI 2 on the RX-V6A and select that HDMI port as the input on the RX-V6A I get audio out of the speakers. I can get audio but no video or video but no audio by selecting one or other of the HDMI ports on the RX-V6A.

I have tried connecting the DP-UB820 directly to the TV an selecting it as a source on the TV. When I do this I get audio from the stereo just like I expected to get when the DP-UB820 was connected via the RX-V6A. This audio is via ARC. So the DP-UB820 can output audio on the HDMI Video Out (Video/Audio) port.

I have tried multiple settings options to no avail. I've also tried various combinations with the cables to validate their integrity.

It seems that there is some interaction between the DP-UB820 and the RX-V6A when the RX-V6A is used to connect the DP-UB820 to the TV that is shutting down the audio on the DP-UB820's HDMI Video Out (Video/Audio).

Any ideas?

Thanks