I know this isn't the highest end audio out there but decent nonetheless. I have an issue with the Video out to the monitor not outputting an image. Here is the scenario:
If the receiver is being used throughout the day for music or TV and then I want to watch a movie, I switch the receiver over to one of the input video sources (doesn't matter which one). All I get on the TV is a blue screen. If I shut off the receiver for a while (presumably to let it cool) and turn it back on, I can get it to output the video. The video has never shut off while being used but only when being switched to.
It seems that heat is the issue but the receiver has two built-in cooling fans with the heatsink. I would think this sufficient. Could better ventilation be needed? I have about 4 inches of space above the receiver and ample room behind it minus all the cords.
If it's within warranty period, try for it. Otherwise I would sell this on craigslist or something and pick up something new. The 805 is a gem, and one of the best receivers ever made (for the money), but plagued by heat problems.
I still have one and haven't run into any problems, but I know there are a lot of complaints with this model. Also, you might want to see if you can upgrade the firmware on this model. Try AVSForum or google for it.
I like the 805. The audio quality was pleasantly superior to many other similarly priced units and I got it for a steal at 620 dollars. It retailed at the time for 1150. Anyway, I don't really want to sell it because I couldn't replace it for what I have into it. There is no firmware upgrade for it per Onkyo. I have thought about taking out the two fans that are in there and the resistors to a lower value to allow a higher running speed and thus more airflow. It would be a little more noisy but maybe worth the tradeoff.
To be honest though, if you take out the amplifier unit, the 805 was a pretty average receiver and is plagued by clicking, fragile hdmi ports, and heat problems. I've got one around and thank god it still works.
The fans in this receiver are probably positioned to cool power amps not the video switching electronics. Try adding an additional fan that would pull air through the receiver from bottom to top.
The fans are positioned at an angle towards the front of the unit. The intake for the fans is the bottom corner of each side at the front. They pull in the air here and then discharge it at the top with the fans blowing directed air across the heatsink. All of the IC boards (and there are a lot of them, all sandwiched on top of each other and linked) are at the rear and completely segregated from the heatsink. I like the suggestion of adding another fan to cool the rear items. The problem is that there is no air intakes at the rear and no place to put a fan. The back half is completely full. I would have to see if there is some way of placing a fan against the top grate and having it pull the air from the unit and out. I will see if I can pull the top off and examine it for a place to put a fan.
I just took the receiver out and the cover off and the fans are motionless. Does anyone know if the fans are supposed to run all the time or only at specific temps. Anyone with an 875 should operate the same as it is the sister to my unit.
Sounds like it is overheating. Usually I can push my 805 to 0dbFS when the ambient temp is in the 60s-70s.
One day the room hit I believe 95F and anything above -35dB and the receiver would shut down.
I have one of those power strips with LED displays that shows power draw. During regular music output, draw from the wall went up from 1.8A to 3.9A--which would be an increase in 250W! Despite this, they didn't seem to do much until the ambient room temp actually dropped.
I received the following reply from Onkyo customer support:
"The fans are not intended to be on all the time, They are attached to the power circuit connected to the amplifier within the system. They should activate when it reaches a certain temp and turning back off when they cool down to another predetermined temp. The receivers normally run at about 80 degrees F above room temp."
I replied back to ask what the parameters were that caused fans to engage. Below is the response:
"I actually spoke with the Technician this morning and he stated that the Heat Sink is what absorbs most of the heat and the fans only activate when it feels an electrical interference to prevent the "protection mode" of the amplifier from activating. Protection mode is when the amplifier shuts down. Therefore, per the technician, there is not set temp for the fans to activate. It is the Heat Sink that does most of the work."