My RX-A820 was within 3/4" of the top of my TV stand. That is, it was significantly taller than my R-V1105. Because of this, it felt like it was running pretty hot.
So I installed CoolerGuys 5v 120mm fans extracting hot air from the upper outer corners of the back of the TV stand. Sure enough, this made the AVR run very cool. Apparently room temp to the touch, but that's not necessarily very accurate...
I purchased a decent IR temp gun recently to find out how cool. Right now, at this moment, it is running at 80f in a room that is 75f - and that's after several hours of usage. I consider that pretty good.
Anyway, the CoolerGuys fans were initially too loud for me personally. I'm a head trauma survivor, so minute noises can make people like me kinda' crazy.
So I picked up a Chinese RoHS 3v 1.5 amp power supply and found that its no load voltage was 3.35. Would that be enough to run 2 CoolerGuys fans? It is.
I bought a 4 pin Molex 6 foot extension cable to connect the 2 fans. Installed a Molex 4 pin connector on the RoHS wall wart using a multimeter and visuals to get polarity right.
Tested 50 times to make sure the fans would start reliably. No problema. However, there is a somewhat concerning delay where it takes about 1/2 second for both fans to start; totally uniform to both fans. But they start every time. Now, they are totally silent.
And BTW, the 80f temp above is with the fans throttled way back as described above.
This is all probably not directly related to the thread, but I figure I'm not the first person to have an AVR run hot to the touch due to new AVR's being significantly taller than older ones.
I'm astonished at how much temp differential is caused by 2 little fans operating at low rpm. I'm also pretty glad.
After this exercise, my PS3 fan sounded loud. So I hung a small towel over that side - still allowing the CoolerGuys fan plenty of ingress. It cut the PS3's fan noise in half, yet it still runs cool. After 5 hours continuous use today, the temp gun says it is running at 94f right now. Not stone cold, but not scary as PS3's go.
Ok, ending my "fan club" project now.
If this seems too oblique, well, the thread has been a little bit slow lately anyway.