Tony,
There is a lot of empty space above the refrigerator. Just pound out the panel with your fist. It is stapled to the frame rails with a brad nailer. There will be a small piece of batting insulation on top of the refrigerator. I removed that. There is a piece of Luan that separates that space from the heat cavity/roof vent cavity. It had a 3/4 inch space that was open at the bottom. Since this was originally set up for the wife’s induction burner, griddle and stand mixer storage, I needed to make it air tight from the outside or the fantastic fan would suck hot air in from the back of the refrigerator.
Rather than cutting a new “back wall”. I used fire retardant “great stuff” foam to lay down a bead, wait a minute, put another bead on top of that etc. till the gap was filled. The same on both sides of the refrigerator.
There is enough room for a home type receiver to fit there. There is already a small wiring hole between that cavity and the one where the original crappy stock radio was. I had to make the hole bigger (3” hole saw) to fit the cord for a power strip, HDMI cables, speaker wiring and enough extra room for airflow.
The cooling will be a a combination of four computer fans.
Two are installed in the side wall of the Thermostat, Radio, TV cavity
See photo
The other two will be mounted in a custom faceplate I have yet to make for the receiver.
Air will circulate in above the refrigerator and out through the fans in the photos above.
Wiring the fans in series (each 12 Volt fan running on 6 Volts) makes them inaudible but supplies good air flow
Here is a photo of the unfinished, but working receiver location.
I will post a photo when I get the faceplate made and installed