Power cycle the modem, router and PCs. Be sure that it is not an ISP/Modem issue. Connect a PC direct to the modem via cable bypassing the router and see if the issue still exists. If the signal is bad from the ISP, you will get poor internet and loss of signal but your WIFI devices will show as connected. Next check the Ethernet cable between the modem and router and replace with quality ones and ensure the connections are good. Ensure your router firmware is up to date. If power cycle router helps, consider reset to factory specs and re-enter your settings.

@ArcherC8 

Thanks, but that didn't/won't help.

I've already tried a variety of combinations and I've isolated the problem to the router with 100% certainty.

Like I said, power cycling the router is the only thing that corrects the problem.

The fact that the devices on wired connections still work fine even when the wireless is out proves that it is not an issue with the modem,ISP, or cables/connections.  Likewise, connecting a PC directly to the modem will prove nothing, since the problem is isolated to the wireless.  i.e. When all of the wireless devices are reporting that there is no wireless network, I can sit down at my wired PC and access the internet through the router with no problems.  Therefore, the problem cannot possibly be the ISP, modem, cables, or the PC.

 

Think about this: My PC is on a wired connection to the router.  My cell phone is on the same router's wifi.  When the wifi drops like I'm talking about, the phone often remains connected, but signals that there is no internet access.  If I try to remote into my PC from my phone at this point, I get an error.  However, the moment I turn my phone's wifi off and switch to the cellular network, I can remote into my PC with no problems.  That alone proves that the ISP and modem are just fine, and that the router's wired connections are continuing to operate normally.  However, everything on the wireless connections suddenly reports that nothing can access the internet, so it is just the wifi networks that are failing.

 

I ensured that the firmware is up to date just before my original post a few hours ago- in fact, there was a firmware update a few days ago that I really hoped was going to fix the issue, but it hasn't.  I'll factory reset the router tonight and see if that makes a difference, but I'm honestly not expecting it to since I didn't really change many settings on it other than inputting SSIDs/security.

@Carl 

There were a couple of T3 timeouts in the modem log, but the most recent was a few days after Christmas, and like I said the wifi issues have been going on almost daily for the last few weeks.  Likewise, there was a note that the modem had rebooted itself due to a T4, but that was on January 1st, so is likewise probably unrelated.

 

I'm questioning your SNR numbers though- from what I've been able to find here, DOCSIS specification says:

256 QAM: 30 dB minimum. 33 dB or higher is recommended.  Most ISPs run 256-QAM in downstream.

The Downstream section on the modem page shows that all channels are 256QAM, and they all show either 38 or 39 dB with a power level of 8 or 9 dBmV (the page I linked said <7 is ideal, but these levels should not cause major problems), so that seems right in line.  Upstream channels don't list a SNR that I see, but the power for each of them is between 32 and 34 dBmV.

 

But like I said, whenever the wireless drops out, anything connected to the router via a physical network cable (or directly to the modem, if we disconnect the router entirely) continues to work just fine.  This by itself should be enough to indicate that the problem isn't in the modem or the service, shouldn't it?

 

Smart Connect has been disabled since we first got the router, since I wanted separate SSIDs for the different bands.  I can try turning it on tonight, but I don't see how having it on or off would cause wifi (and just wifi) on all bands to drop.

@tweak45 

 

I also have the C5400 router but I am NOT running the latest firmware - I am on firmware version 1.2.2.  You mentioned that your problems only started relatively recently.  Is it possible that your wi-fi problems are related to the 1.2.5 firmware - which is also relatively new (for this router) ??  If you think there may be a connection maybe you could try downloading the 1.2.2 firmware from TP-Link's website and "downgrading" your router to the previous firmware.

 

Just a thought . . .

@gandalf1369 

And a good thought!  I've got a ticket open with support, which of course means that the problem that we've been seeing almost every day didn't happen last night.

I didn't realize that they offered downloads of old firmware versions, so if we can't get the problem to go away using the current one, I'll definitely try switching back to an older version instead.

Thanks for the idea!

@tweak45 Did you ever find a resolution to your WiFi cutting out? If so what was the fix to your issue?

 

I have the Archer C5400(US) Ver: 1.0 and mine cuts out every 2-3 days. The wifi light will stay blue or turn orange and the wifi just stops working. Anyone connected directly to the router is fine, but everything on wifi is disconnected from the internet.

 

I am running the latest software patch Firmware: 1.0.4 Build 20170731 from 7-7-2017 (seriously, there isn't a more recent software update?!?!).

 

The only thing I have NOT done is reset the unit to factory settings and start over. Was seriously hoping a software patch would be released to fix this issue.

 

Any help is appreciated.

@Dasandman21 

 

No. I went back and forth with support several times and finally convinced them that the problem was indeed the router and not my internet connection.  Once that might feat was accomplished, they agreed to replace it under warranty. And since the original C5400 was no longer being made, they sent a C5400X instead, so free upgrade! 

Seriously though, the C5400X has been flawless so far. My only complaint is that the parental controls and network-level filtering/blocking absolutely suck.  (This wasn't an issue at the time, but the kids are a year older now and have discovered the wonders of the internet)

Hello

 

I have Archer C5400 v2 EU. Some time ago I also started to get the problem with WiFi cutting out. Lights on the router went off and all WiFi was gone (2,4 and 5)

 

First I updated to some Beta Firmware recommended in some other thread n forum - now I use 1.2.5 Build 20210308 rel. 64655

 

Unfortunately it didn't solve the issue. 

 

As lately I was fighting with my kids PS4 (disassembly, cleaning and exchange of thermal pads and thermal paste) I thought maybe the topic is the heating of the router. I opened it (4 screws under the rubber pads/legs)  but I didn't do the whole disassembly - I had no time for all the antennas cables connection etc so I just blew some can compressed air to remove evntl. dust - it wasn't much. I assemblies router again and thought that as a trial I will improve airflow (router was really hot at the bottom side) so I added sth like 2cm height legs for the router (I used regular felt ppl stick under the furniture not to scratch the floor).

 

Since then - 2 weeks now not a single crash, WiFi cut our or anything else. The router is working fine providing sth like 80-90% of ISP speeds.

Interesting. Please update us again in several weeks or so.