AC86U sometimes powers completely off during reboot

[nlurker]

Its nothing to do with the schedule reboot to be honest... I don't use schedule reboot and sometimes when i reboot the router i got the problem! The only thing we know for sure is that this problem happens when you reboot the router

We also know for sure that it does not happen every time you reboot the router.

 

[Asad Ali]

The only concentrate thing we know so far is this issue only happens on soft reboots either via Web UI or over the SSH. I've never experienced this issue on hard reboots.

 

[Froghut]

I also experience this behavior sporadically on my 86U. Is there any way to help identify the problem? Gathering/providing logs, something like this?

 

[Val D.]

Is there any way to help identify the problem?

Well, we are trying to identify the problem in last 12 pages in this thread.

 

[JDB]

I discovered yesterday that I had a cru job hanging and so many instances of it eating up RAM. I wonder if having very little RAM remaining causes this issue?


Sent from my iPhone using Tapatalk

 

[gattaca]

The last time I had my A86U do this was a week or two ago when I updated the current Merlin FW and hit "reboot" on the web GUI after it had finished. Then after 15 mins --> no router b/c it had indeed powered itself off. Power button off / on and she booted right up into the new FW. That's all I can add to this discussion. Very strange and very annoying.

FWIW, there were some postings around the power-supply not be sufficient during a boot-cycle and then someone posted a message on another thread that there was a log message indicating that might be related. We glossed over that? FWIW, it is a darm common thing for a PSU to go into protective mode when overloaded and boot times, with USB->SATA/SSD would be peak use. But I'm like you guys, I've rebooted the AC86 across Merlin FW upgrades and it does not do this all the time. Like LD&D, this stuff is sitting behind a high-quality UPS with some Furman AV voltage regulation HW I had unused sitting in stock. So I do not think it's incoming power supply to the ASUS PSU.

I have an single external USB->SATA (UGREEN) to an small SATA SSD attached to handle amtm tooling. I don't suppose that power draw + the AC86 could be enough to tip over some protective measures which cannot be reset without physical intervention? Could the PSU actually be shutdown when we find it this way? IDK.

I'm sure the PSU on these routers is about as cheap as they can make it! If anyone finds a good plug-compatible higher amperage unit which does not require me to cut the cable off my working ASUS PSU unit, yell. I wish ASUS would use a standard 2.1/2.5mm plug and 12V unit. But I get why the 19V.. lower amperage. Many Laptops use 19-20V for that same reason but that plug size is the PITA b/c it's only ASUS routers.

I also found the STP discussion interesting.

If anyone knows the exact size of the AC86 male pin, wouldn't one of these work?
Found some speces that say Connector Size: 4.0mm / 1.35mm
Note: I verifed this size on several sites.. and viewed that it is a very small pin, so the 4mm x 1.7mm would NOT be a great fit.

There are comments below that the inner pin may be too small for the first unit so I'd pause. The 2nd unit has varying sizes.. BTW check out the comments in the first link about the ASUS OEM units being a problem...

https://www.amazon.com/dp/B007O24GES/?tag=snbforums-20

or

https://www.amazon.com/FIT-POWER-Adapter-Charger-Monitors-Westinghouse/dp/B078Y9S1MX/ref=sr_1_6_sspa?keywords=ASUS+router+120W+19V+POWER+ul+listed

 

[Grisu]

@gattaca
use this DC power adapter plug 4,0mm x 1,35mm male to 5,5mm x 2,1mm female: https://de.aliexpress.com/item/32846046054.html
or this 2.1mm plug with cable: https://de.aliexpress.com/item/3298...000&pvid=c5ccbb59-669d-4b0f-9906-cbbb795e39fb

 

[gattaca]

^^^ Wow thanks I had not even thought of a very common 5.5 by 2.1 to 4.0 to 1.35 converter. That makes locating a GOOD PSU which is UL listed, etc - much easier to source!

 

[SSeyer]

I love these RT-AC86U routers because of the VPN throughput and backup/failover capabilities and core Linux access! I'm benchmarking these at over 200Mbps OpenVPN throughput in my lab. Kudos for the geniuses who are responsible for Merlin and making these routers a tremendous solution for VPN networks. I have about 10 of these deployed in a site to site OpenVPN network with a lot of tweaking to get failover to cell phone hotspot networks on Internet failure working smoothly, so I do a lot of remote reboots. I've seen the following problems:

- problem with the reboot powering down the unit (very frequently)
- disconnected ethernet cable locking up or powering down the unit (once or twice)
- toggling light on/off switch in the middle of the back of the unit powering down the unit

I've noticed that when I make changes to either the jffs/scripts files or the STP enable/disable suggested in one of the posts, I can SIGNIFICANTLY increase the chances of the reboot power down problem, although it is not consistent...as indicated in the thread...NOTHING is consistent about the failures. I have one site (ADV) that seems to more consistently fail (reboot power down) than others when I make changes to the jffs/scripts files. I've seen problems with multiple versions (384.12 and 384.13 in use currently).

I'm inclined to suspect the problem is power related. The stock power supply is low in amps compared to comparable routers I've used which are usually 12v (but pretty comparable in overall wattage). I generally tend to look for power supplies that supply about 60+ watts of power...the more amps, typically the less chance of power related problems. My next step is to try a higher amperage power supply, although the small connector makes it challenging to find power supplies in abundance, and I wish Asus would have used a more common connector size.

 

[Jack Yaz]

I love these RT-AC86U routers because of the VPN throughput and backup/failover capabilities and core Linux access! I'm benchmarking these at over 200Mbps OpenVPN throughput in my lab. Kudos for the geniuses who are responsible for Merlin and making these routers a tremendous solution for VPN networks. I have about 10 of these deployed in a site to site OpenVPN network with a lot of tweaking to get failover to cell phone hotspot networks on Internet failure working smoothly, so I do a lot of remote reboots. I've seen the following problems:

- problem with the reboot powering down the unit (very frequently)
- disconnected ethernet cable locking up or powering down the unit (once or twice)
- toggling light on/off switch in the middle of the back of the unit powering down the unit

I've noticed that when I make changes to either the jffs/scripts files or the STP enable/disable suggested in one of the posts, I can SIGNIFICANTLY increase the chances of the reboot power down problem, although it is not consistent...as indicated in the thread...NOTHING is consistent about the failures. I have one site (ADV) that seems to more consistently fail (reboot power down) than others when I make changes to the jffs/scripts files. I've seen problems with multiple versions (384.12 and 384.13 in use currently).

I'm inclined to suspect the problem is power related. The stock power supply is low in amps compared to comparable routers I've used which are usually 12v (but pretty comparable in overall wattage). I generally tend to look for power supplies that supply about 60+ watts of power...the more amps, typically the less chance of power related problems. My next step is to try a higher amperage power supply, although the small connector makes it challenging to find power supplies in abundance, and I wish Asus would have used a more common connector size.

Pinging @Val D. who did extensive power supply testing iirc

 

[Val D.]

Pinging @Val D. who did extensive power supply testing iirc

RT-AC86U hidden software/hardware issue. Too late for ASUS to fix now, I guess. Different production year, stock/custom software, stock/custom power supply... all the same. I personally never managed to find a solution. The last two routers I played with (2019 production) were both affected, right after first firmware update, on first restarts. Apologies for the delayed reply.

 

[shark]

RT-AC86U hidden software/hardware issue. Too late for ASUS to fix now, I guess. Different production year, stock/custom software, stock/custom power supply... all the same. I personally never managed to find a solution. The last two routers I played with (2019 production) were both affected, right after first firmware update, on first restarts. Apologies for the delayed reply.

I personally got tired of all the issues with asus software and hardware on the rt-ac86u like crashing on trend micro stuff, this issue that the routers turns off when rebooting or the router rebooting when i disable and enable my network adapter on my pc... i sold the rt-ac86u to never buy an asus router ever again! Going to ubiquiti products now!

 

[miazza]

I personally got tired of all the issues with asus software and hardware on the rt-ac86u like crashing on trend micro stuff, this issue that the routers turns off when rebooting or the router rebooting when i disable and enable my network adapter on my pc... i sold the rt-ac86u to never buy an asus router ever again! Going to ubiquiti products now!

I share your view but this is an unknown issue when you buy the router it I is a shame nobody can fix it.
I understand that Merlin cannot do anything on this part of the SW but .... ASUS shoul !

 

[SSovets]

I read all 12 pages of this thread in hope of a solution after I became sick with this problem, but no luck... For me this (router going dark after soft restart) happens, if I remember correctly, all the time. Tried disabling STP, after restart the router is black.
I'm still curious about the possibility that the power supply is not powerful enough, but haven't seen any conclusion, so don't know if it would be worthwhile to spend some time and money looking for a more powerful option (PSU + adapter, probably). Will try to switch the PSUs with the old AC68U, it has the same amperage, but who knows, maybe it's better quality?..

 

[elorimer]

If I reboot my 86U by unplugging the power and plugging it back in, it comes up fine. If I turn off the power button and turn it back on, it comes up fine. It is just the software reboot that sometimes has this problem.

I would think the most stress on the power supply would be the hard start, not the soft restart, so I'm not following how it would be the power supply.

 

[Val D.]

Will try to switch the PSUs with the old AC68U, it has the same amperage, but who knows, maybe it's better quality?

Don't waste your time. I was testing with 65W laptop power supply, still the same issue.

 

[HorseCalledHorse]

Just switched to an AC86U to run Merlin on my network after having run Tomato on various Linksys routers (going back to the WRT54G) and lately a Netgear R7000 for 14 years. I was getting low on memory (possibly due to a memory leak in the version of pixelserv I was running with Diversion) and rebooted via the GUI during troubleshooting. I was shocked when instead of rebooting the router just turned off. Hit the power button on the back and it came back to life, with everything running well ever since. But I was thrilled to find this thread today and learn I'm not alone. Probably a quirk I can live with

 

[nlurker]

Just switched to an AC86U to run Merlin on my network after having run Tomato on various Linksys routers (going back to the WRT54G) and lately a Netgear R7000 for 14 years. I was getting low on memory (possibly due to a memory leak in the version of pixelserv I was running with Diversion) and rebooted via the GUI during troubleshooting. I was shocked when instead of rebooting the router just turned off. Hit the power button on the back and it came back to life, with everything running well ever since. But I was thrilled to find this thread today and learn I'm not alone. Probably a quirk I can live with

The main caveat is to NEVER reboot the RT-AC86U when you are not in the same room to make sure it comes back up.

 

[SSovets]

But there has to be an explanation for this behavior, and hopefully a not very complicated fix. It's a great router otherwise, and I, personally, don't see any good reason to upgrade to AX yet, so I want to stick with my AC86U with it for a while.

 

[Asad Ali]

But there has to be an explanation for this behavior, and hopefully a not very complicated fix. It's a great router otherwise, and I, personally, don't see any good reason to upgrade to AX yet, so I want to stick with my AC86U with it for a while.

The problem is @RMerlin have never been able to reproduce this issue on his router thus he can't even start to diagnose it, perhaps one of us should send him a confirmed faulty unit of ours for testing.