It could be the receiver, but cables are a common source of problems. It isn't clear if you connected the Blu-ray player to the projector using exactly the same cables as you used with the receiver. That would be one way to test the cables. Also, you need to make sure the HDMI cables are fully seated in the correct sockets. Sometimes they seem to be plugged in but are not making a good connection. They pull out easily, especially the thick, stiff ones.
Be sure to do a full reset of the receiver so that you are starting from a known good configuration. The previous owner might have configured it in a strange way which is now causing confusion for you. See the receiver's owner's manual for reset instructions.
Also, do your tests using the same video disc each time. For initial tests, I suggest using a DVD instead of a recent Blu-ray disc. Some cables and hardware settings will pass a low resolution video signal (like that from a DVD) but have problems with high resolution (1080p) BD video.
I hope these suggestions help a little.
edited to add:
You might try contacting the previous owner to find out how they were working for him.
Marantz SR7009 avr + MM9000 amp --> Atmos 7.1.4
Fronts=NHT 2.9+AC2, FH+TM=DefTech PM1000, LCR+TM amped
Last edited by Selden Ball; 08-06-2014 at 02:45 PM.