Help, cannot get 5.1 sound from ANTHEM AVM30

Connected ANTHEM AVM30 with OPPO95 with 6 RCA interconnects and it only pays 2 channel. Also using XLR for 2 channel and that works fine. I have had it work with Coax but somehow cant get that to work anymore but want to stick with the 6 RCA's as this is utilizing the DAC from the OPPO. Toslink connected to cable box works fine in 5.1
I have followed the OPPO set up instructions and also the ANTHEM's, but I still may have something wrong, unless of course something is wrong with the ANTHEM.
Any suggestions please? Thanks.
Hi Ehom

I have the AVM/20 so basically the same setup. You need to do two things initially.
1) make sure you have not selected stereo down mix in the oppo and
2) make sure you are playing a true multichannel source

The oppo used to come with the AIX calibration disk that had a speaker test track for all speakers. Did you try that?

Also does your cable box offer coax digital out? Try that too.

Those are initial starting points.

I thought I had the same problem with my Anthem AVM 20. Try unplugging the unit, wait 5 minutes and plug it back in.