*ISSUE FOUND* RT-AC66U - 5 Ghz radio not working on 380.65_4

[adampk17]

Background: I have a RT-AC3200 running 380.65_2 and I had a RT-AC66U running 380.65_2 on the other end of the house running in AP mode. The AC66U was configured with the 2.4 GHz and the 5 GHz radios using the same SSID names as the AC3200 for their respective bands. This was working wonderfully for several weeks.

When 380.65_4 came out I decided to upgrade the AC66U as a sort of test before upgrading the main router. It seems that since about that time the 5 GHz radio on the AC66U does not function. The device's page says the radio is enabled, the 5 GHz light on the device is on, but it's not working. I confirmed this by changing the SSID of the 5 GHz radio to something unique, it doesn't show up in any site surveys done on other devices.

Steps taken so far:

Downgrade to 380.65_2 and reset to factory defaults. - 5 GHz radio still does not work
Re-upgrade to 380.65_4 and reset to factory defaults. - 5 GHz radio still does not work

The change log for 380.65_4 says this:

- FIXED: Some models would sometime randomly fail to start one
of their wifi radio, possibly due to a hardware design
issue. Partly revert the 380.65 changes that removed
the automatic reboot if one radio was disabled at boot
time, but reduced the maximum number of reboots to 1.
​

Seems that 380.65_4 may have actually caused this issue for me.

What should I try next?

 

[adampk17]

I should add that yesterday I also tried resetting the AC66U using the unplug and hold the WPS button method. No change in behavior for the 5 GHz radio.

The web UI, the light on the device, those things all indicate that the radio is on. Using the mobile app, it also says the radio is enabled, unless I try and look at the status of traffic across the device. The 5GHz radio is non-existent there.

 

[adampk17]

Any suggestions for kick starting this device? Perhaps something more heavy handed than a factory reset? Perhaps installing the newest Asus firmware might do something. Otherwise I'm out of ideas. Unless perhaps the radio has gone bad.

 

[L&LD]

After flashing back and forth with the firmware, have you every performed a proper reset to factory defaults?

https://www.snbforums.com/threads/n...l-and-manual-configuration.27115/#post-205573

https://www.snbforums.com/threads/rt-ac66u-slow-wan-to-lan.12973/page-3#post-269410

https://www.snbforums.com/threads/faq-nvram-and-factory-default-reset.22822/


With the issues you're having, you may have to do the above steps twice (don't laugh; it has worked for a few here).


Are you setting the channels manually? If you are, make sure they are set to within the range of channels your specific devices (and region) supports.

 

[adampk17]

I'm not setting the channels manually. I've left it on auto.

I will try your suggestions.

 

[L&LD]

I'm not setting the channels manually. I've left it on auto.

I will try your suggestions.

Yes, try setting the channels manually. If that doesn't work, a full factory reset is necessary to see if indeed this is a setting (make sure to use manual channels going forward) or if it truly is the router hardware.

 

[adampk17]

Which method of resetting the router to factory are you suggesting? I've used two so far.

 

[L&LD]

Which two have you used?

I would at the minimum use the WPS reset button and format the JFFS partition too after installing the firmware you want to use. This will require several reboots of the router; be patient in between the reboots.

Quoting RMerlin:

you will have to turn off the router, press the WPS button (on Asus routers), then turn on the router. Wait about 10 seconds, then release the WPS button.

 

[adampk17]

The UI also has a reset to factory button.

 

[adampk17]

Three WPS button resets, spaced more than an hour apart, and the situation with the 5 GHz radio remains unchanged. :-(. The router web page says it's on but it doesn't show up in site surveys done from other devices.

 

[FatherLandDescendant]

Three WPS button resets, spaced more than an hour apart, and the situation with the 5 GHz radio remains unchanged. :-(. The router web page says it's on but it doesn't show up in site surveys done from other devices.

I assume you have the radio set up to broadcast its' ID? Cause if you turn broadcast ID off it won't show up in a site survey, if it does it'll be on the list showing a channel is being used but the ID field will be blank..

 

[adampk17]

I assume you have the radio set up to broadcast its' ID? Cause if you turn broadcast ID off it won't show up in a site survey, if it does it'll be on the list showing a channel is being used but the ID field will be blank..

I'm looking for the 5GHz radio right after my resets, so it is on default settings. I double checked just now, SSID is set to broadcast and the SSID is ASUS_5G.

 

[adampk17]

Update:

I flashed the latest version of the firmware that Asus had on their site. This, by itself, didn't appear to fix the issue. Then I started playing with the 5GHz setting. I set the channel bandwidth from 20/40/80 MHz to 20 MHz. I also changed the control channel from AUTO to 36. I hit apply and boom. The 5 GHz SSID shows up as available.

I'm going to play around some more and see if I can figure out if I can break it again with a particular setting or if "jiggling the handle" like I did just shocked it back to life some how.

 

[adampk17]

Some interesting news.

If, on my RT-AC66U, the 5 GHz radio's channel bandwidth setting is set to either the 20/40/80 MHz setting OR just 80 MHz, the radio appears not to work, the SSID never shows up in site surveys on either my laptop or my iPhone. I'm using Acrylic Wi-Fi Home on my laptop for the site survey.

If I set the channel bandwidth to either 20 MHz or 40 MHz, the radio is available as expected. I tried this on both Merlin's 380.65_4 and whatever the latest is available today on Asus's site. It behaved the same on both firmware.

So, is the 80 MHz channel bandwidth supposed to be supported on the RT-AC66U and perhaps broken on mine? Or is this an option that should be hidden from the choices on this router?

Merlin?

 

[adampk17]

Bump. Hoping for a knowledgeable comment on the 80MHz observation.

 

[sbailey4]

Running AC-66 here and never had the issue you describe. Setting is on 20/40/80. Currently on 380.66 b2 but no issues on 380.65x either. So AC-66 does support it. I get 300Mbps+ download speeds over wireless AC on laptop and iPhone.

[Edit] Just for grins I just changed it to 80 mhz only and all is well.

 

[adampk17]

Running AC-66 here and never had the issue you describe. Setting is on 20/40/80. Currently on 380.66 b2 but no issues on 380.65x either. So AC-66 does support it. I get 300Mbps+ download speeds over wireless AC on laptop and iPhone.

[Edit] Just for grins I just changed it to 80 mhz only and all is well.

Do you have the B1 revision?

 

[sbailey4]

Do you have the B1 revision?

No its the older one. Also I have had a strange issue or two in the past when using Johns firmware in that speeds would go to crap after a flash. Factory resets did nothing but the clear NVRAM by command line resolved it. Not sure why the factory default using the GUI and WPS button process didn't but twice in the past the command line solved strange things for me. May be worth a shot.

 

[adampk17]

No its the older one.

Same here. Odd

 

[a5m]

Don't know if you ever got this sorted out, but just in case anyone else is running into the same issue like I did recently after updating our RT-AC66U to the latest Merlin 380.70 and seeing the 5GHz was disabled, I found a thread on tomshardware with the following instructions that worked:

Switch off the unit at the back, wait 10 seconds, depress reset button and then switch unit back on. Keep holding the reset button for 10-15 seconds. The Blue Power Light LED will blink slowly. Let go of the reset button and the Power light will continue to slowly blink. Let it blink for another 30 seconds before turning the unit off via the power button. Wait 10 seconds and then turn the unit back on. Wait for unit to restart and both 2G and 5G lights to illuminate.