ASUS RT-AC86U Issue/Dead (Eth4 LED Only)

meeekael

New Around Here
Hello,

I've had this router running fine for 2 or so years now. Had a few issues initially with not maintaining connection, but a firmware uograde fixed that.

My issue now is that the unit won't power on at all. I came home from work at lunch to no wifi, checked the router and the only LED visible is ETH4, and it is very pale. Windows sees nothing (ethernet cable is disconnected). PSU has 19.4V on a multimeter, but that isn't accounting any sort of load. I have a friends PSU to test it with after work.

Neither factory reset nor recovery work (When power comes on, only LED ETH4 lights up - no power LED.)

Any ideas? Apologies if this gets asked regularly, I've found it really difficult to find threads with the same fault. All I've found is a dead reddit thread and this: https://www.snbforums.com/threads/a...-asuswrt-merlin-driver-breach-warranty.55761/

They appeared to have luck on eth4 with the recovery tool, so I guess ill start there when I get home. Mine feels pretty hardware fail to me though...
 

OzarkEdge

Part of the Furniture
Hello,

I've had this router running fine for 2 or so years now. Had a few issues initially with not maintaining connection, but a firmware uograde fixed that.

My issue now is that the unit won't power on at all. I came home from work at lunch to no wifi, checked the router and the only LED visible is ETH4, and it is very pale. Windows sees nothing (ethernet cable is disconnected). PSU has 19.4V on a multimeter, but that isn't accounting any sort of load. I have a friends PSU to test it with after work.

Neither factory reset nor recovery work (When power comes on, only LED ETH4 lights up - no power LED.)

Any ideas? Apologies if this gets asked regularly, I've found it really difficult to find threads with the same fault. All I've found is a dead reddit thread and this: https://www.snbforums.com/threads/a...-asuswrt-merlin-driver-breach-warranty.55761/

They appeared to have luck on eth4 with the recovery tool, so I guess ill start there when I get home. Mine feels pretty hardware fail to me though...

It's dead. I had two die the same way:



Asus replaced one; I replaced the other.

OE
 

meeekael

New Around Here
Thought as much. Cheers for the info. Will get the warranty ball rolling .

Is warranty 24 or 36 on these normally?
 
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L&LD

Part of the Furniture
It depends on which region you bought it in.
 

meeekael

New Around Here
I think its 36 in New Zealand so thats small win I guess!

So failing a warranty replacement, what would you recommend as a replacement? Same price range as the 86U. Is AX worth it? Doesn't have to be ASUS, use case is concurent gaming and streaming/htpc/nas, gigabit fibre. Thank you!
 

bitsbytes

Senior Member
And another one bites the dust. Sorry for your troubles. I'm starting to worry, my original ac86u is almost two years old now :(. Seems like a lot of ac86u routers have been dying lately.
 

L&LD

Part of the Furniture
You seem to have the 2018 'original' version of the RT-AC86U which has known hardware issues for some users. The latest manufacturing dated examples are more robust (time will tell though).

There is nothing better than the RT-AC86U for the same price range.

If you can get it replaced for the same one under warranty, you should be okay for a while (if you get a newer 2019/2020 manufacturing dated version). If you need one until the replacement comes, the RT-AX58U will be a good stand-in until the more powerful RT-AC86U gets replaced (and then it can be used in AiMesh mode, or sold, as needed.
 

Flipmode11

Regular Contributor
I have a similar issue with mine. Cannot even ping 192.168.1.1 when in recovery with IP 192.168.1.10, etc.
Just bought a new one. Dead within a month! Sent it back.
About to buy ANOTHER one ... but now I'm skeptical that devices advertised as "new" are actually refurbished... Hmmmm
 

Rezzor

Occasional Visitor
I had the same issue and had it replaced under warranty. Mine was a 2020 Vietnam version so it not limited to the 2018 China versions. In fact the replacement they sent was a 2018 version that’s been working great (for the couple weeks I’ve had it)

 
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Flipmode11

Regular Contributor
Oh okay so maybe the one I sent back was also 2018?
I still have another AC86U here. How do I see what model it is? Under the router? In the configuration? on the retail box?
Thanks.

Worked perfectly for a long time on Merlin..... Then one day just suddenly went unresponsive.

Q?? Does anyone know which antenna on AC86U are 5GHz and 2GHz? They're numbered 1,2,3,4 (but inconsistently).
I have some larger and higher DBi antenna on the device, but 5GHz is worse than before. 2GHz is much better. Maybe I need 5GHz compatible antenna? These antenna are new but 15 years old! Found them in the garage :D lol
 

CaptainSTX

Part of the Furniture
I still have another AC86U here. How do I see what model it is? Under the router?

The date of manufacture and country are listed on the router's back in plain text. Because of the bad reputation that 2018s earned some sellers of "refurbished units" have put another tag over the ASUS label to hide this information.
 

Teryro

New Around Here
I had the same issue last week, one day the router died (2018 made in china). I took it to a shop and they pointed out that a component is busted/bursted due to heat.
It's imposible to destinguish what the componet SN was and even then it's probably not availble on the market to buy.
Lesson to be learned: support the right to repair bill in your country (explained here by Rossman Louis
)
 

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Tech9

Part of the Furniture
It's imposible to destinguish what the componet SN was and even then it's probably not availble on the market to buy.

MT3125, about $1.50 + shipping cost.
 

Tech9

Part of the Furniture
No problem. You need equipment, materials and skills to replace this one.
 

Oracle

Regular Contributor
Oh, sh&*, one more component to cool.
I thought I was done modding this thing to make it last.
Thanks, Tech9!

Edit: Any other offenders on this side of the board?
I've been thinking for quite some time to buy one of those thermal imaging devices and now there's a shortage at my local supplier. Can't easily see what emits the most heat.
 
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Tech9

Part of the Furniture
Any other offenders on this side of the board?

I believe the greatest offender is RoHS solder. It causes numerous issues in thermally stressed boards.
 

ntec

New Around Here
MT3125, about $1.50 + shipping cost.
I also had the same issue so I replaced the MT3125 chip but the router still will not work after replacing the chip. I guess something else on the board is faulty for me.
 

Tech9

Part of the Furniture
If you were able to replace this IC, you perhaps can diagnose what’s wrong. There is a way to test boot the router with this IC removed.
 

gattaca

Senior Member
FWIW, I replaced all my RT-AC86U about 18 months back for this same reason - random, instant death - usually from the MT3125 voltage control chip.

I had 1 of 4 x RT-AC86U I had pulled from service, cleaned up, reset to factory defaults and was preparing to sale. When I powered it on to take working photos, it went "poof" and game over - literally. I think I sold it "for parts only" for $20 after that.

There are various opinions about the venerable RT-AC86U. Initially I, and many others _highly_ recommended it and it appeared to be a "solid design." Over time though, as various issues started surfacing, I've tempered my enthusiasm and will not recommend it anymore. This same router also had another infamous issue - "failing to power on after a reboot". I (and a few others) did _seem_ to solve the "failing to power on sometimes after a reboot" by using a higher amperage ASUS power-supply. I think hmmm, back to that MT3125...

I replaced the remaining 3 x RT-AC86U with 3 x RT-AX86U and then eBayed the remaining working units. @Tech9 is 100% on-the-money about the lead-free solder. It very prone to thermal stress cracking. (It's an industry-wide issue.) So far I've had those RT-AX86U ~ 2 years and they have behaved very well. I do supplement the cooling on these (as I did for the RT-AC86U). So YMMV. Good luck on the repair. I have another 3 - RT-AC1900 in service too. These seem to built like tanks and are still be sold as well.

https://www.snbforums.com/threads/is-my-ac86u-toast.68578/page-2
 
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