RT-AX86U random reboots

[Log]

I have been unstable on all latest firmwares. (asus or merlin) and started a support thread with Asus, tells me my warranty expired 11/27/22 ouch. Should have started to ping them earlier as I have been in a mess regarding this router for 6 months now. have done all that can be thought of. Reverted to my older ac87u today as can't afford dropped calls this week while I battle how to get this premiere piece of Sh.. figured out. my AX86U is one of the early versions manufactured likely October 2020. I am sure Asus knows the issues, they are just acting unknowledgable.

 

[soid]

I came here from Google results searching RT-AX86U restarts in 2026. Not a lot on the Internet about this problem and how to troubleshoot. My RT-AX86U just started restarting randomly in the past two weeks. Sometimes, it restarts every few minutes; other times it works fine for a few hours, but still the problem returns.
The firmware is 3.0.0.4.388_24401 (not Merlin)

Here is what I've tried so far:
1) Not much in the logs (Advanced Settings > System Log). The log from before restart is erased. There are logs from "May 5" as mentioned earlier in this thread.
2) I tried factory reset (via Web interface, then holding reset button for 10 seconds, and starting while holding WPS button). It didn't help.
3) I never enabled AiProtection. The only features I was using are VPN server (disabled after factory reset), port forwarding, and static IPs for a few devices.

Not sure what else to try? Should I install Merlin firmware? I've seen somewhere that it can show the temperature, so I wonder if it could be that. Anything else I could try? The device is 3 years old, so out of warranty.

 

[degrub]

What did you do for configuration after the factory reset ?

Did you ever accept the TrendMicro "license" for AiP ?

Does the power brick plugged into the wall feel Hot, Warm, or cool ( room temp) ?

You can try pointing a USB fan at the base of the router to try to improve cool air flow into the router case. The router is out in the open and not in a cabinet, etc, correct ?

Unless you made configuration updates, firmware updates, etc just before the random reboots started, it sounds likely for a hardware failure of some kind - ram, power (on board or supply), solder joint, etc.

 

[soid]

After factory reset I configured the same SSID and password and I don't think there were many other decisions to make. I don't recall accepting TrendMicro "license" for AiP, I don't think so. Maybe in the past I did (like when I just purchased the router).
The power brick is slightly warm, I would call it warm. But I'll check it some other times of the day. I feel like I've seen it quite warm recently.
I don't have a USB fan, but I'll try to figure something out for improved ventilation. The router is pretty much in the open on the floor; it's a feet away from the wall, and somewhat close to a steam heater, about 3 feet away which I think is not too close.

 

[ColinTaylor]

1) Not much in the logs (Advanced Settings > System Log). The log from before restart is erased. There are logs from "May 5" as mentioned earlier in this thread.

This could indicate faulty or corrupted flash memory. Save the System Log and upload it to www.file.io. Then post a link to it here so that we can examine it for clues.

 

[degrub]

After factory reset I configured the same SSID and password and I don't think there were many other decisions to make. I don't recall accepting TrendMicro "license" for AiP, I don't think so. Maybe in the past I did (like when I just purchased the router).
The power brick is slightly warm, I would call it warm. But I'll check it some other times of the day. I feel like I've seen it quite warm recently.
I don't have a USB fan, but I'll try to figure something out for improved ventilation. The router is pretty much in the open on the floor; it's a feet away from the wall, and somewhat close to a steam heater, about 3 feet away which I think is not too close.

Steam heaters ( we call them radiators) work by both warming the immediate air at the metal and by radiating infra red wavelengths. It would be hard to determine if 3 ft away is causing any issues though while the router is operating and generating its own heat. It drops off in proportion to 1/r where r is the distance between the source and receptor. If it has been in this location for a long time, then whatever happened has happened. Anything substantial blocking the line of sight path between them should mitigate most of the theoretical issue though.

A warm power brick is good generally. Can still be an intermittent issue. More likely on the board itself though. Definitely check out the corrupted flash memory mentioned by Colin though.

 

[soid]

This could indicate faulty or corrupted flash memory. Save the System Log and upload it to www.file.io. Then post a link to it here so that we can examine it for clues.

Here is the log about a minute after fresh restart: https://limewire.com/d/cOR8z#jWWzg8dKc6

 

[ColinTaylor]

Here is the log about a minute after fresh restart: https://limewire.com/d/cOR8z#jWWzg8dKc6

The log file is inconclusive. The log does cover multiple reboots, so it's not loosing old log entries. However, there's no indication that there's been a software crash or that it soft-rebooted itself.

So my suspicion would be that the power is being interrupted in some way. Perhaps the power brick is failing, or there's some heavy load on the same circuit that causes a power spike.