I'm also seeing wAP ac crashing under load (reboot by watchdog timer) - in my case, it's a "NAT router on a stick" (separate tagged VLANs for WAN and LAN sides) and CPU load from sustained high traffic on the wired side only (wireless mostly idle) is sufficient to trigger the issue. Despite reduced CPU frequency (500 MHz - minimum that could be set) the temperature sensor shows 58C when mostly idle (CPU load of a few percent). BTW, probably unrelated but voltage reading is too low (35.8 to 35.9 V), device is powered through about 10 m of good quality copper cat5e FTP cable, from a 802.3af switch (Nortel 5520-48T-PWR) which shows 48.5 V / 76 mA / 3.686 W.
I just had a look at wAPAC's on 2 sites, one with a HP 802.3at/af switch and one with a CRS328withPoEandkitchensink. I was surprised to see the wAPAC devices reporting only around 37V at both sites which I agree is too low, considering the CRS328 said it was 52V! The CRS328 can do 802.3af/at or 26V dumb PoE on each port so I changed the ports with wAPACs on them to use the low voltage mode and now the CRS328 AND the wAPACs show 26V *each*! I'll see over the next few days if the lower voltage corresponds to a lower operating temp. Already one wAPAC dropped from 70C down to 61C last I checked.
So there is something awry with the wAPAC - the 37V value is wrong or something inside the power circuit is dropping a lot of voltage and maybe getting hot - maybe a voltage protection diode clamp is conducting when it shouldn't be?!
Well the same we had partial overheating on some (every time different) wAPac with 57V from CRS328!
Yesterday, i reset PoE ports with 19 x wAPac in 26V (low PoE) and now - there is no overheating!! (60-68 C)
In Past, i saw on Dude different values from 60C to 92C!!
I made notification in Dude to send alarm, when AP has termperature more than 78C, because after 80C (on board) AP can't forward traffic and can't send relay IP from client to DCHP server. In that case system / reboot helped to drop temperature to 62-65C
Whats up with from CRS328 57V (auto) setting and wAP ac?
Mikrotik staff? Can you explain it?
PS: 2 marekm - thanks for the suggestion!!