Roamio Plus/ AV Receiver not getting along

My previous setup:



Tivo Series 3 HD connected by HDMI to Pioneer VSX1019AH connected by HDMI to Samsung UN55F7100. No problems.



New setup:



Tivo Roamio Plus connected by HDMI to Pioneer VSX1019AH connected by HDMI to Samsung UN55F7100. No dice.



With the above setup, when I power on the Roamio, initially I see the "Welcome, Starting Up" screen with the Tivo man. After 15 seconds, the video signal is lost. This process then repeats every 2 minutes or so.



If I connect the Roamio to the TV directly, it works without a hitch. I have tried multiple cables to no benefit. I reconnected the Series 3 set and it worked normally. All the other AV input components (AppleTV and Xbox One) are working normally.



What is different about the Roamio that it does not work in the exact same setup as my Series 3 HD unit? How can the receiver be preventing the Roamio from starting up? Is there a setting I can change in the Tivo or the AVR to make this work?



FYI, Kuro-link on the AVR and Anynet+ on the TV are both set to off.



Thanks for any help.