AC86U overheats with fw 386

[Poncik]

Hello all,

I am having overheating issues with my AC86U since I upgraded to the 386 firmware. I tried both the official 3.0.0.4.386.41634, 9.0.0.4.386.41994 and 386.1-merlin versions and it was all same. I realized the problem when we started to have disconnection issues during online meetings and video calls. I checked the system logs and the below messages kept repeating every couple of minutes:

Feb 13 10:18:41 kernel: CPU1: shutdown
Feb 13 10:20:12 kernel: thermal cooling_device1: turn on CPU#1
Feb 13 10:20:12 kernel: CPU1: Booted secondary processor
Feb 13 10:21:12 kernel: thermal cooling_device1: turn off CPU#1
Feb 13 10:21:12 kernel: IRQ6 no longer affine to CPU1
Feb 13 10:21:12 kernel: CPU1: shutdown
Feb 13 10:22:31 kernel: thermal cooling_device1: turn on CPU#1
Feb 13 10:22:31 kernel: CPU1: Booted secondary processor
Feb 13 10:23:36 kernel: thermal cooling_device1: turn off CPU#1
Feb 13 10:23:36 kernel: IRQ6 no longer affine to CPU1
Feb 13 10:23:36 kernel: CPU1: shutdown

I am also checking the CPU temperatures from the http://router.asus.com/ajax_coretmp.asp link and it is always around ~99c. I tried restarting and factory reset but nothing worked so far. I am not running VPN or AirMesh or any other fancy feature. The CPU is mostly idling. We have 4-5 wifi clients and 1 LAN Nextcloud box for backing up photos.

In order to see if this was specific to v386 I downgraded to the latest v384 fw and it brought the CPU temp down to ~82c. I upgraded back to v386 again because I don't want to have any security vulnerabilities.

Is there anybody else experiencing the same issues? I live in the EU and still have the warranty, should I RMA it?

 

[VANT]

Did you perform a factory reset after the upgrade to 9.0.0.4.386.41994 and set up the router manually, without restoring the configuration from a file?
Do not use 3.0.0.4.386.41634, it have thermal bug.

 

[Poncik]

No, I did the factory reset before upgrading to the 9.0.0.4.386.41994. So, do you recommend to use the beta fw?

 

[OzarkEdge]

No, I did the factory reset before upgrading to the 9.0.0.4.386.41994. So, do you recommend to use the beta fw?

Yes. Install RC2-11 41994, reset it, and configure it from scratch.

Beta - ASUSWRT 386 RC2 public beta with full functions AiMesh 2.0 (continued)

I know how to do it @ForkWNY everyone seems to be missing the point Not sure if it's different per router type (in my case, GT-AC5300)...to reset a node, login to the web UI. Head to AiMesh > Click on Node to reset > Select "Management" > Remove Node. This effectively seems to pull the node...

www.snbforums.com

Reset FAQ
Reset Button/webUI Restore
WPS Button Hard Reset

The reset must be done after installing the firmware.

Thanks for this tip! router.asus.com/ajax_coretmp.asp

OE

 

[Poncik]

I installed the RC2-11 41994 and did the factory reset. I configured everything manually. The coretemp is hovering around 92c now without too much activity and syslog isn't showing any errors. I hope it doesn't overheat under load.

I think 92c is still quite hot. Do you think a fan would help or is there a way to under-volt the AC86U?

BTW, thank you all for the quick response and the solution

 

[ForkWNY]

SSH into your 86U...type the following command in the terminal:

pwr show

Paste the output. Just want to double-check that CPU Wait is ENABLED.

A fan nearby may help...or placing the 86U in a cooler, more open location might also help decrease the CPU temp. The 86U is cooled passively, using vents. It does not have any internal fans.

 

[Poncik]

Yes, it is enabled. Here is the full output:

$ pwr show

Power Management Configuration
Functional Block           Status
CPU Wait                   ENABLED
Ethernet Auto Power Down   ENABLED
Energy Efficient Ethernet  DISABLED
Switch Deep Green Mode     ENABLED (status:Deactivated)

 

[ForkWNY]

Looks good. I'd suggest trying a small fan nearby to help with airflow, or relocating your 86U if it's inside a closet or boxed-in somewhere that does not allow it to get decent airflow.

 

[OzarkEdge]

Yes, it is enabled. Here is the full output:

$ pwr show

Power Management Configuration
Functional Block           Status
CPU Wait                   ENABLED
Ethernet Auto Power Down   ENABLED
Energy Efficient Ethernet  DISABLED
Switch Deep Green Mode     ENABLED (status:Deactivated)

That is correct. But 92C is still on the hot side... but not the 99C you first reported. Mine is at 83C, down from 92C with CPU wait disabled.

Maybe 92C will avoid your earlier disconnects and CPU protection shutdowns, but it may suggest your CPU heatsink interface is not so good.

If really motivated, you could reestablish the CPU heatsink and thermal paste/foam. Done right, it would likely improve it, but what a nuisance.

Cycle power on the router just in case that makes a difference.

OE

 

[Poncik]

It is very annoying indeed. I ordered a USB fan for 13EUR. It is quite an upgrade if you think the router was for ~130EUR. I will keep this router as long a possible but it will probably be my last Asus router.

 

[bbunge]

67C with a fan I bought from Amazon (currently unavailable) running on slow.
A while back Asus acknowledged the CPU heating and stated they were working on a solution. I feel that more than enabling CPU Wait was being investigated...

 

[mromero]

It is very annoying indeed. I ordered a USB fan for 13EUR. It is quite an upgrade if you think the router was for ~130EUR. I will keep this router as long a possible but it will probably be my last Asus router.

This is a known issue with the 386 firmware - both the genuine Asus, and Merlin's implementation. It has been widely discussed.

The solution is to purchase a fan or use the previous release, such as Merlin 384.19, or await for a fix from Asus (CPU wait is NOT the problem).

The consensus appears to be that the 386 firmware is more for the AX models.

The 384.19 works very well on the Asus AC-86U router - no overheating. Placing a business class router in front of the Asus will protect your network from unpatched Asus vulnerabilities etc. Like you, I am looking at other brands for my next purchases as they are getting better.

 

[DarkKnight75]

One of my other reasons why i went back to latest .384...

 

[nickie]

according to the information on the page posted before, my ac86u is running at 74º, and is with 386_41994 for the last week or so. At home, we are simple users and thus do not tax the router much. It's a new router (1 month) and most likely the thermal compounds are at their best, hence the results.

 

[ATLga]

Ditto on that. No issues with mine either, running at 71 Celsius right now. Three year old Ac86u. People keep saying known issue and yes it was a known issue that was fixed. Also widely discussed.

 

[OzarkEdge]

according to the information on the page posted before, my ac86u is running at 74º, and is with 386_41994 for the last week or so. At home, we are simple users and thus do not tax the router much. It's a new router (1 month) and most likely the thermal compounds are at their best, hence the results.

Yeah, 41994 dropped mine from low 90s to low 80s... at 79 now. 15% below 100C is comfortable operation.

OE

 

[maxbraketorque]

It is very annoying indeed. I ordered a USB fan for 13EUR. It is quite an upgrade if you think the router was for ~130EUR. I will keep this router as long a possible but it will probably be my last Asus router.

A fan will drop the temperature by 20C which will get the router down to typical territory, but the fact that your router is running at 92C suggests that the heat sink attachment is sub-optimal. Redoing the heat sink would likely make a big difference for your router.

 

[Poncik]

I slapped on a 92mm USB fan and now it is down to ~60c from ~95c. Great! Now I have only one USB port available on the router

 

[bluzfanmr1]

I slapped on a 92mm USB fan and now it is down to ~60c from ~95c. Great! Now I have only one USB port available on the router

The router will recognize a usb hub/splitter if you need more ports.

 

[Centrifuge]

I assume the CPU is getting hotter because it is doing more processing, has there been any definitive explanation of what extra processing is taking place, especially if Trend Micro is disabled?