RT-N66U reboots randomly. Log included

[Gazeebo]

The router will reboot usually when my wife turns on her computer which is connected through wifi.
But other times, it will just reboot itself.

I am using a Motorola SB6121 modem and have Comcast.


The router reboots itself, the modem does not.
I've tried factory reset as well as using the latest Asus firmware and after that didn't help I tried the latest stable Merlin release.

The problem did not exist when I was using a $25 Rosewill router that unfortunately died and was then replaced with the RT-N66U.

This is the entire log file after the reboot happened.
Log file : http://pastebin.com/PHLtcT9Z

 

[wh7qq]

Admittedly, I have not looked at the log, but I would look to to the wall brick as the source of the problem. Do you have USB drives connected? If so, remove them and see if the problem persists. It may be that they are putting too much demand on a marginal power supply. In that case, a quick and inexpensive fix would be a powered USB hub. A new power supply is an allternative fix and perhaps more permanent but if you have a USB disk drive connected to the router, it will probably draw too much power even from a new supply.

 

[Gazeebo]

I do not have anything attached to the router except for 1 wired connection to my computer and the wire to the modem.
The rest is wireless. I am using the power brick that came with the router.
It is hanging on a wall mount with an open back (~2 inch from back of router to wall)to allow for plenty of air flow.

Besides, why would they create the possibility through hardware AND software to attach storage to the router if it can't handle the power draw?

 

[wh7qq]

See this link: http://www.snbforums.com/threads/asus-rt-n66u-dead-not-switching-on.24886/

Good that you aren't overloading the USB ports. The ports were designed some years ago when the expected and specified USB loads were light. I doubt they ever expected a big hard drive to be attached. You can also overload your house wiring even in the presence of a circuit breaker...why is that possible?

I don't know about you but when I see an entire log of a continuously running device, my old eyes glass over. I leave that to younger eyes who understand the cryptic entries better than I. I don't know if the linux version in the N66U supports the "more" or "less" commands but it would be more helpful to see a segment where the router rebooted itself. Even so, if there is some kind of abrupt power disturbance, the logs may just stop recording and restart with the reboot.

The power brick is still a good place to start looking. Switching supplies like those used in the N66U tend to beat the stuffing out of their capacitors...nature of the beast. Ultra-low equivalent series resistance (ESR) caps are expensive so manufacturing "cost reduction" may be a factor in premature aging and all caps are not created equal. Unfortunately, it is not easy to monitor supply voltage in the router without taking it out of the case. It would be nice if Asus/Broadcom provided a command like "vcgencmd measure_volts" as is available in the Raspberry PI/Broadcom devices.

Faced with the prospect of having to replace the router, I would be inclined to strip back the conductors on the supply cable (careful to keep the two apart) and measure the voltage there with the router up and running. It should be 19 v dc. carefullly wrap the bare cables with electrical tape before putting it back in service. You could also have bad caps on the router cpu board...harder to check and repair.

 

[Zirescu]

What firmware version are you running?

 

[CaptainSTX]

See this link: http://www.snbforums.com/threads/asus-rt-n66u-dead-not-switching-on.24886/

Faced with the prospect of having to replace the router, I would be inclined to strip back the conductors on the supply cable (careful to keep the two apart) and measure the voltage there with the router up and running. It should be 19 v dc. carefullly wrap the bare cables with electrical tape before putting it back in service. You could also have bad caps on the router cpu board...harder to check and repair.

You don't need to strip the wires of the power cable to check voltage. The pins on the test cable for your multimeter will make the connection just fine.

Proving that your power supply outputs 19 Vdc doesn't really help diagnose the power supply. You also need to look at the AMPs and if the power supply is functional under load.

 

[mstombs]

You don't need to strip the wires of the power cable to check voltage. The pins on the test cable for your multimeter will make the connection just fine.

Proving that your power supply outputs 19 Vdc doesn't really help diagnose the power supply. You also need to look at the AMPs and if the power supply is functional under load.

The wire stripping is to allow Voltage measurement under load.

 

[CaptainSTX]

The wire stripping is to allow Voltage measurement under load.

If you have have access to clamp meter that will read DC Amps/ Milliamps you can split the power cable down the center ( without exposing the copper conductors ) and clamp one lead and get a direct read of DC Amps under load.

The Fluke 773 Clamp milliamp meter is a nice tool as it should be for $950. Most people would just spend $10 - $20 for a replacement power supply. If it works problem solved, if not return the power supply.

 

[wh7qq]

Most mere mortals don't have access to a clamp-on dc milliampmeter but many of us do have a DVM handy. At under $10 for a pretty decent little meter, anyone who owns a computer/network or a home should get one if they don't already. I should have added that it would be a good idea to stagger the strip-back areas so as to prevent an accidental short that would probably kill the supply.

 

[TonyH]

You don't need to strip the wires of the power cable to check voltage. The pins on the test cable for your multimeter will make the connection just fine.

Proving that your power supply outputs 19 Vdc doesn't really help diagnose the power supply. You also need to look at the AMPs and if the power supply is functional under load.

I'd rather measure current and using 'scope make sure adapter is not putting out too much noise or ripples(sign of sick switching power supply usually caused by failing electrolytic caps.

 

[Gazeebo]

What firmware version are you running?

Merlin 380.59_0

I am considering just replacing the entire router. It's giving me more trouble than it's worth. Since the problem seems to occur to so many people but in so many different ways I feel like this is going to be a never ending battle. I hate replacing an otherwise perfectly fine router just because I can't figure out the problem, but there are times I am doing things online that are quite a hassle to have to restart when the connection is interrupted.

This seems like a good contender to me :

https://www.amazon.com/dp/B00Z0V2NQ8/?tag=snbforums-20

or

https://www.amazon.com/dp/B00F0DD0I6/?tag=snbforums-20



I do not have a voltage meter but I'll see if I can get my hands on one.
This morning the router rebooted again when my wife turned on her computer, which is connected wirelessly with a rosewill usb adapter.
As I said before, most of the time when her computer gets a new DHCP lease from the router it reboots. I tried setting hers up with a fixed IP address but that didn't fix the problem unfortunately because I am guessing other wireless devices are causing the problem too (or something entirely different! )

I was hoping someone could possibly explain some things in the log file to me. I wish I had some log information right before the reboot, but everytime it reboots it starts with a fresh log file.

 

[L&LD]

Just a thought. Do you have any non alphanumeric characters in your ssid's, passwords and/or device names?

 

[mstombs]

...
The Fluke 773 Clamp milliamp meter is a nice tool as it should be for $950.

I picked up a dead N66 off fleabay, used one of those universal power supply tips to make up a test lead so it could be powered from a lab instrument with simultaneous display of Voltage and Current. There wasn't a problem with the PSU! - was an internal 3.3V DC-DC regulator that had failed, wouldn't advice anyone to try this but I do now have 9 FR9888 's in stock!

 

[Gazeebo]

Just a thought. Do you have any non alphanumeric characters in your ssid's, passwords and/or device names?

Lol yea, like everybody else in the world.
Not in SSID and device names though.

 

[L&LD]

Lol yea, like everybody else in the world.
Not in SSID and device names though.

You may want to test without them then.

 

[wh7qq]

Merlin 380.59_0

I am considering just replacing the entire router. It's giving me more trouble than it's worth. .

Gee, great. Send me the old RT-N66U...I'll even pay you for postage

First, dust off that Tektronics scope in your garage and check out the ripple on your power supply

Seriously, decent and cheap DVMs are available maybe at your local Home Depot but on-line from Amazon or Harbor Freight. I keep several of these around the house for quick checks on a lot of issues. Some even have built in battery testers. They tend to quit but at these prices, they are disposable.

 

[Zirescu]

Would be handy to know what non-alpha numeric characters are in the device name to see if I can replicate it here.

 

[Gazeebo]

The router password only uses a @ of the non-alpha numeric characters, as I have done with all my other routers in the past.
But I generally also have MAC address white listing on, which I have turned off to see if it made any difference. It didn't.

 

[coarser]

Hi Gazeebo,

I'm running into similar issues as you're having with my Asus N66R (retail store version of the N66U). I detailed a good chunk of it over on the DDWRT forums http://www.dd-wrt.com/phpBB2/viewtopic.php?p=1034096&highlight=#1034096 and some more subsequent posts there.

I've been through a ton of different firmwares namely DDWRT, tomato, merlin regular and john's SDK5 fork, stock ASUS, and openwrt which doesn't fully support the N66U but does boot on it. I've also done the nvram settings flush from telnet, from the recovery page, and through the various firmware GUIs.

I've also tried the power adapter from my Asus N56U which is the same as the N66U adapter and have also tried a PWR+ adapter from amazon but my router keeps crashing.

I've been noticing that a lot of N66U owners are having issues recently and it could be due to faulty hardware but it seems odd that it's all happening around the same time. Then again they've probably sold a million of these things so it's bound to happen in clusters.

My last steps are to poke around with a multimeter in a last ditch effort but at this point it's probably better off in the trash heap.

 

[Zirescu]

Yeah, your log file didn't have anything of mention in it.