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wAP ac overheating?Crashing

Posted: Mon Jun 04, 2018 3:29 pm
by ivicask
I have one wAP ac whos giving me problems for some time, but unfortunately is also out of warranty so i just wonder what are normal temps for this device?When i copy files over 5ghz interface at around (450mbit/s ) speeds, the router hits 80c and than randomly starts crashing and its not visible on network until it cools.Idle temp of device is 59c, in 23C ambient temp.

I also tried open it up and i replaced thermal paste on that metal plate, which seams to help a bit, but problem persists and crashes on heavy loads.

Re: wAP ac overheating?Crashing

Posted: Wed Jun 06, 2018 1:09 am
by WebLuke
Sounds like heat isn't the only problem, my wAP AC is in my house now running at 71C in a room that is 29C. But that is with little load. Mikrotik says it "Tested ambient temperature: -40 to +50C". I have had mine for just under a year this month, only having some though put download problems that are depending on the devices I use (slow TX fast RX). Have you tried running it with out the case to see if extra air keeps it from over heating? If you limit the speeds down (300Mbps or less) dose it stay stable?

Re: wAP ac overheating?Crashing

Posted: Mon Feb 04, 2019 11:24 am
by UpRunTech
Sounds like heat isn't the only problem, my wAP AC is in my house now running at 71C in a room that is 29C. But that is with little load. Mikrotik says it "Tested ambient temperature: -40 to +50C". I have had mine for just under a year this month, only having some though put download problems that are depending on the devices I use (slow TX fast RX). Have you tried running it with out the case to see if extra air keeps it from over heating? If you limit the speeds down (300Mbps or less) dose it stay stable?
It's a concerning problem. Last week I had 3 wAP AC's situated in a school library all reboot themselves when 80 students each with a combination of iPads, Macbooks and Chromebooks assembled in the library and tried using their devices. I am monitoring one of the units now and with a constant 30Mbit traffic on the 5GHz radio it's 73C in a 20C room. They were purchased before the cAP AC's came along. It'll be interesting to see if this crash mode happens again.

Re: wAP ac overheating?Crashing

Posted: Mon Feb 04, 2019 2:42 pm
by marekm
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.

Re: wAP ac overheating?Crashing

Posted: Tue Feb 05, 2019 1:24 pm
by UpRunTech
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?!

Re: wAP ac overheating?Crashing

Posted: Thu Mar 28, 2019 8:27 am
by nuffrespect
UP!

Re: wAP ac overheating?Crashing

Posted: Thu Mar 28, 2019 8:46 am
by nuffrespect
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?!
Hi!
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!!

Re: wAP ac overheating?Crashing

Posted: Thu Mar 28, 2019 9:45 am
by nuffrespect
Update
sent message to support@mikrotik to investigate situation

Re: wAP ac overheating?Crashing

Posted: Thu Mar 28, 2019 11:07 am
by storp
I see occasional reboots on my two wAP AC's. Been measuring temperature via SNMP for a while to see if that is the problem but haven't been able to pinpoint that as a root cause. I do think it's more stable now with latest release of routeros. Earlier I had one of the AP's rebooting at least once or twice a week but I see longer uptimes now. Please share any findings you might do!

Re: wAP ac overheating?Crashing

Posted: Fri Oct 25, 2019 12:29 pm
by nmt1900
I must admit, that this same issue has been haunting at different customer locations for some time now.

Problem seems to be related to somewhat unexplainable small CPU background activity, which is usually 5% at most and is absent, when device operates normally. All this occures even when there is no client or other network activity and then even small client load rises temperature even more - at worst scenario to the point of "watchdog reboot" (temparature peaking even at > 85 degrees C). Reboot cures all that and even significantly higher client load (with related higher CPU activity) can not rise temperature even close to the levels observed at this state of abnormality.

Worse of it all is that this happens at quite rare occasions and is thereby hard to reproduce or even "catch" if no alert notification is set up by means of some sort of monitoring system.