I spoke of downgrading to clarify if you had.
You stated "I had the latest firmware on it last week, but this didn't help at all...:"
That implies you no longer have the latest, thus I asked the question. And latest version can also be the General release, which is the latest available on the support site, but far from the latest release when you include the spars. I don't have nearly enough time working on the forum to go through a persons post history to see if I have worked with them before and what their configuration is. I work in Xerox as a 2nd level support rep, that is my actual job, the time I spend here is between calls and not my job at all, just my way of keeping my skillset up to date.
The tray 5 thing can't be cleared, if it is empty you get a message, closing the tray makes no difference, we in support have asked for a way to disable it, we are always denied a way.
While I don't think Airprint has any bearing on the issue, I won't say it isn't the cause, just that we have had no reports of it. After you see if the fans stop simply by unplugging it from the LAN, then start disabling protocols one at a time when back on the LAN to find the culprit. (Do Airprint and MOPRIA at the same time though, they are nearly identical)
It also can't hurt to try an Immediate Disk Overwrite, theoretically there could be something stuck somewhere that is causing the machine to do work constantly, you lose nothing of importance by trying except 20-30 minutes of it being offline while it runs.
Now after all that is done, the next step would be a complete wipe (Altboot) of the device, if it still does it at that point there is no question, the machine has something wrong in hardware and would need to be stripped down. So hopefully it doesn't get that far.
Did you ever get the OVH thing cleared up? What exactly was in the trace (if it got done) at the point of failure?
why do you talk about downgrading ??? My firmware is 073.010.126.28110
And no, it's not in a dusty environment, nor in a hot one, nor close to the wall...
The only thing that's wrong with the printer (yet totally unrelated) is that is permantly shows a 07-535-00 warning, because there's no paper in tray 5 (bypass), although it's not open...
Could the fact that AirPrint is enabled cause the printer to go into a 'less deep' sleep mode ??
I'll try to unplug the network cable and see if that makes a difference...
Having it serviced is not an option either, as it was bought on Ebay... ;-
Is it too close to the wall? (Should be about 6 inches or more at the back, a foot on either side minimum)
Dusty environment leading to clogged vents? (Clean via compressed air)
By "Was on latest firmware" does that mean you proceeded to downgrade it? (Latest ends with .28110)
If you unplug the Network cable do the fans still never really stop?
my 7830 doesn't show any errors, but while in sleep mode, the fans (one at least) constantly starts, then stops for a few seconds, then restarts, etc...
I had the latest firmware on it last week, but this didn't help at all...
I've seen in forum that some types of network communication can cause this kind of behaviour (on other models at least), but I don't know where to look at...
My network is not that complicated (@home...), and this definitely can't be normal... could it be some sort of (temp) sensor that's dead or ???