AC86U Heatsink Mod

[Tivi]

The one at 86C is about right, the one at 97C perhaps has failed or incorrectly installed thermal transfer pads. You can fix the CPU temperature easily, but the router has more issues. Read what I found inside. I had a full bin of dead AC86U's, kept 10 for experiments, repaired 3 using the others for parts, kept 1 in my routers collection. My recommendation is to replace them with something else when you have a chance.

Thanks for the info. I am the original owner for the one that is running at 97-98 since 2018 and I only recently observed the CPU turn down due to high temp. Otherwise it has been very stable. I got the second one from ebay last year (also 2018 model) as well but running at 86.

A few days ago I got a refurb model from Amazon that was made in 2020 and running mid 60's. So looks like they used slightly different thermal solution now.

Let's see if I can salvage the one that is running hot and extend its life for a few more years. I will let you know how much the temperature drops after the thermal pad replacement.

 

[slurmsmckenzie]

A few days ago I got a refurb model from Amazon that was made in 2020 and running mid 60's. So looks like they used slightly different thermal solution now.

That's interesting - I have a 2020 model and the thermal setup looks identical to the other photos I've seen on here. Mine ran at around 70 when idle (only a single wired client connected, wifi on but nothing connected) where ambient is about 25.

I just tried a version of the mod on the CPU only - a 15x15x2mm copper shim (couldn't find anything thicker for non-ridiculous prices on Amazon) with a 0.5mm thermal pad (Thermalright Extreme Odyssey), so:

CPU -> pad -> shim -> Arctic MX-4 -> heatsink

Has brought the temp down to 58, not a huge improvement but I'm happy I bothered. Sure it would be better with just a 2.3mm copper shim with thermal paste on each side, but couldn't find anything like that.

 

[slurmsmckenzie]

I had a full bin of dead AC86U's, kept 10 for experiments, repaired 3 using the others for parts, kept 1 in my routers collection. My recommendation is to replace them with something else when you have a chance.

I already mentioned this on another thread but I've been kind of stupid and bought an AC86U in August 2020 but never got around to doing anything with it until now. Have modded the CPU to hopefully help with longevity etc. but you mention that there are more issues than just that. Trying to decide whether it is worth bothering using it to replace my AC68U or just not bother to avoid potential issues down the line - our main router needs to be rock solid and especially don't want 2.4 wifi issues.

Have started reading about pfsense and going down that rabbit hole, know it is overkill but I like the idea of having separate access points....

 

[Tivi]

I already mentioned this on another thread but I've been kind of stupid and bought an AC86U in August 2020 but never got around to doing anything with it until now. Have modded the CPU to hopefully help with longevity etc. but you mention that there are more issues than just that. Trying to decide whether it is worth bothering using it to replace my AC68U or just not bother to avoid potential issues down the line - our main router needs to be rock solid and especially don't want 2.4 wifi issues.

Have started reading about pfsense and going down that rabbit hole, know it is overkill but I like the idea of having separate access points....

I have been using the Asus routers for over 10 years starting with 66 then the 68 and now 2 of the 86's. I think the heatsink is engineered to fail over time and probably a percentage of them has problems out of the factory but in general they are still one of the best on the market.
I don't think there is any single router that beats the coverage of a single 86. It should cover any house up to 3000 sqft by itself. If your area is bigger than just get a second 86 and connect them via Ethernet. I tried to use my 68 as an Aimesh node but the transition was not as good as with the dual 86's.

 

[slurmsmckenzie]

I have been using the Asus routers for over 10 years starting with 66 then the 68 and now 2 of the 86's. I think the heatsink is engineered to fail over time and probably a percentage of them has problems out of the factory but in general they are still one of the best on the market.
I don't think there is any single router that beats the coverage of a single 86. It should cover any house up to 3000 sqft by itself. If your area is bigger than just get a second 86 and connect them via Ethernet. I tried to use my 68 as an Aimesh node but the transition was not as good as with the dual 86's.

Thanks for the info, it is good to hear from happy owners of the 86. Think my biggest concern is the 2.4 wifi dying, we use it for Squeezeboxes and an IP camera which are essential and I just don't want to be having to recover it or constantly reboot it when it is the main router. We also work from home (three VPN connections) and I don't want to replace the rock-solid 68 with anything less stable. But then it is sat here doing nothing and there seem to be plenty of people running them just fine...

If I do use it then my plan is for it to cover the majority of the house from the first floor (including the new loft conversion room) and use the 68 in media bridge mode to provide some wired ports to a new study downstairs. My daydream is to setup a pfsense router and get some decent access points around the house with wired backhaul to create a great mesh system, but that is unlikely. More realistic would be a pfsense router and some access points with a combination of wired and wireless backhaul, which is what I'll do if I don't make use of the 86 (or if I do and it fails on me).

 

[Tivi]

The 86 is an evolutionary successor of the 68 series. The 2 areas where it shines compared to the 68 is: the significantly better 5 GHz performance and SmartConnect helps devices to migrate between 2.4 Ghz and 5 Ghz.

 

[Tech9]

but you mention that there are more issues than just that

Yes, but it doesn't mean every AC86U will fail. You may get lucky and yours may work for years with no issues.

The 2 areas where it shines compared to the 68 is

It's a completely different hardware with much faster 64-bit CPU, running on newer Linux kernel. No comparison.

 

[OzarkEdge]

I've been kind of stupid and bought an AC86U in August 2020 but never got around to doing anything with it until now.

Yep... and you still haven't done anything with it.

OE

 

[Tech9]

Yep... and he doesn't have to do anything, if the router is working properly.

 

[slurmsmckenzie]

Yep... and you still haven't done anything with it.

Yep... and he doesn't have to do anything, if the router is working properly.

Very true! This has been helpful, thanks for the thoughts, it definitely helps - I think I should put the pfsense pipe-dream aside for the time being and concentrate on making something out of my AC86U purchase. If nothing else I should be able to test how stable it is to a certain extent before I make it the main router. And I know where to look for help if I have any problems

 

[Tech9]

Use stock Asuswrt on AC86U. In my tests it's more stable than Asuswrt-Merlin 386 releases, on this router in particular.

 

[SwampKracker]

Have started reading about pfsense and going down that rabbit hole, know it is overkill but I like the idea of having separate access points....

Switching to pfsense for the firewall and letting wireless routers be only access points was an excellent decision. I wish I had tried pfsense sooner...

 

[OzarkEdge]

Very true! This has been helpful, thanks for the thoughts, it definitely helps - I think I should put the pfsense pipe-dream aside for the time being and concentrate on making something out of my AC86U purchase. If nothing else I should be able to test how stable it is to a certain extent before I make it the main router. And I know where to look for help if I have any problems

I can manually commission my AiMesh in about 20 minutes using my install notes; first was 2xRT-AC68U, then 2xRT-AC86U, and now as is noted... the basics are similar for all.

OE

 

[slurmsmckenzie]

Use stock Asuswrt on AC86U. In my tests it's more stable than Asuswrt-Merlin 386 releases, on this router in particular.

Oh, okay.... wow, I thought the AC86U would be the start of my Merlin adventure. I knew that I needed to nuke the thing from orbit anyway so maybe I should stick with stock in that case.

Switching to pfsense for the firewall and letting wireless routers be only access points was an excellent decision. I wish I had tried pfsense sooner...

Now you're going to get me looking at pfsense compatible fanless mini PCs again I appreciate the amount of knowledge available online and vidoes on YT about pfsense, would be nice to find someone detailing a low-key home setup like I'm aiming for though - most stuff I can find is people plugging into high-end prosumer or fairly serious server hardware. Makes a good demonstration but I'd like to hear about how it fits together for folks that use it to replace a single router in a family home environment too.

 

[Tech9]

Switching to pfsense for the firewall and letting wireless routers be only access points was an excellent decision.

No. Home routers don't support VLAN's and even simple Guest Network is an issue.

I thought the AC86U would be the start of my Merlin adventure.

Then skip the latest 386.4 and install/test with 386.3_2. It's older, but works better.

 

[slurmsmckenzie]

I can manually commission my AiMesh in about 20 minutes using my install notes; first was 2xRT-AC68U, then 2xRT-AC86U, and now as is noted... the basics are similar for all.

I have bookmarked your install notes, they are much appreciated and I will definitely reference them if I try AiMesh. At the moment I have an AC68U, AC86U and an old N56U doing a good job as a downstairs access point. Given that I would plan to use the AC68U as a media bridge to give wired access to some new devices downstairs, I'd been assuming AiMesh wasn't really an option - pretty sure the N56U doesn't support it. Unless it would be more recommended to use the AC68U as an AiMesh node instead of a media bridge? Would that still give the same performance to wired devices on a different floor? Have to admit that after some reading I did wonder whether media bridge mode would be less risky than setting up AiMesh.

 

[slurmsmckenzie]

No. Home routers don't support VLAN's and even simple Guest Network is an issue.

I guess doing it this way is a good start though? I have looked at VLANs a few times and always come away dizzy after hours of research with the conclusion that they are probably too much effort and may not even be what I want / need. In my case, I like the idea of our IP camera being on a separate VLAN. But I don't have an NVR or anything, instead there are 3-4 devices on the home network which view the camera directly via a browser interface. In this setup, I cannot see how it would work moving the IP camera to a separate VLAN because then we could not view it from our other devices.

I like the idea of a segregated guest network for sure, but at the moment... well, we don't really have many guests these days anyways, since early 2020....

Then skip the latest 386.4 and install/test with 386.3_2. It's older, but works better.

Thank you for the advice, that is really appreciated - I just updated it to 386.4 but I will look to downgrade in that case. Stability is all I am interested in really. If the Asus stock is better for this device though I am happy to go with that. I think one of the things that attracts me to a pfsense solution is the idea that I am simplifying the piece of equipment which is facing the outside world, so that hopefully critical updates are less of a big deal which could cause random problems with wifi or whatever. I do feel like I am throwing a dice every time I update my AC68U, although to be fair I have never seen problems with it - but I know others have needed to downgrade to previous versions again many times with Asus routers (and other brands too I'm sure). I like tinkering but I'm not a huge fan of re-configuring my main router every few months to try and ensure a trouble-free upgrade - I guess I'm lazy ;-)

 

[SwampKracker]

No. Home routers don't support VLAN's and even simple Guest Network is an issue.

pfsense is not a "home router", but a commercial grade firewall that most certainly can handle VLAN's. Take a look at the documentation some time.

Guest Networks are not an issue. That is the point of a firewall, to block traffic between interfaces or VLAN's, which is exactly what I do with pfsense.

My post was meant to encourage @slurmsmckenzie to give pfsense a try, not derail this discussion about thermal management of Asus routers.

 

[Tech9]

Unless it would be more recommended to use the AC68U as an AiMesh node instead of a media bridge? Would that still give the same performance to wired devices on a different floor?

AC68U has a firmware bug/limitation when used as AiMesh node - LAN ports are limited to 1/2 speed. Also, not every firmware offers stable Media Bridge mode on AC68U - you have to experiment. The ideal situation is AC86U as single router. Second best is AC86U as router and AC68U as wired Access Point. Wireless AiMesh with AC86U and AC68U may or may not work for you. Expect additional complications if your AC86U is running Asuswrt-Merlin - AC68U may not want to join AiMesh.

I guess doing it this way is a good start though?

Yes. I use pfSense router/firewall. It's boring, just works.

 

[Tech9]

Take a look at the documentation some time.

Netgate 5100 user.

Guest Networks are not an issue.

Now you are going to do Guest Network with Asus routers in Access Point mode?