TM-AC1900 help! - practically invisible wifi network

[ktwetzel]

Hi all, brand new guest to the forum. Hoping someone can help me out

I bought a TM-AC1900 (Tmobile AC68u), and went through the process to revert it to the non-tmobile firmware (followed these steps). The firmware reversion seemed to go off without a hitch. Currently have it running the latest Merlin firmware (380.69) and set as an access point for my network (I also have the same issue as below using the newest Asus firmware, 382, as well). It's connected to a normal AC68U I've had for years that acts as my main router.

The wifi network is setup with it's own SSID, but the wifi signal is practically invisible. Most of our phones and laptops can't see the network at all, or it will pop up for a few seconds and then disappear. I have an old Linksys WUMC710 media bridge that can consistently see the SSID, and I was able to connect my desktop via this and had network access (though at only 30-40 Mbps speeds compared to ~250Mbps speeds connected to the base router which is further away). Wired performance is great (>500 Mbps).

I've tried setting the device up as a normal router, in AP mode, and they all have the issue with the practically non-existent wifi performance. Since I have been able to connect with the media bridge, it's obvious the wifi hardware isn't a complete lemon. Unfortunately, I didn't test the wifi with the prior TMobile firmware, so I can't confirm if this was an issue before the firmware revisions.

Any thoughts or suggestions on how to correct / resolve? Any suggestions or tips are greatly appreciated; I don't have much background in networking; just my own minor tinkering with my existing AC68U. I did try this, but I didn't roll back to the old Merlin fw they suggested, and it didn't seem to have an impact. I've reset the NVRAM since then. I'm hoping I didn't just kill the equipment, but I can't imagine that's the case since it does broadcast and I have been able to successfully connect to it...

WUMC SSID view (the ASUS_5G is the SSID coming from the TM-AC1900 set as an AP):

Current 5G wifi settings (issue occurs on both 2.4 and 5 G):

 

[TonyH]

Is your wireless surveying tool see the signals with good strength? Sure you have an app. on cell phone or inSSIDer of Acrylic.

 

[ktwetzel]

I don't have a surverying tool, and the apps I have (network analyzer lite, fing) only seem to provide details on the network you are connected to. Unfortunately, iphones seem to have far fewer options than android in this space, but I don't have an android phone I can easily access. I have been able to verify that multiple devices all struggle seeing the AP SSIDs.

 

[ktwetzel]

using wifi analyzer on my laptop ~7 ft from the router (unobstructed), the 5GHz network was at -79dB

 

[pjv]

Exact same issue here. I bought this TM-AC1900 a few weeks ago and finally today had the opportunity to convert to AC68U and flash Merlin on it. The AC68U conversion was smooth. I loaded the latest Merlin 384.3 beta on it and everything seems to be working well except that the radio signal is so weak that I have to sit next to the router with a laptop to connect to it at all.

I was thinking that since it works when sitting next to it, it's kind of like the radios are not connected to the antennas so I was about to tear the thing open and make sure the antenna wires are actually connected. Thought before I did that I'd do a little googling to see if anyone else had seen and fixed this problem already.

 

[pjv]

Additional info.

I've now done a bunch of factory resets, reflashed three different CFE versions from https://cfeditor.pipeline.sh/, flashed both Merlin 384.3 beta and the latest release of @john9527's fork onto the router and then finally did break down and tear it open physically just to satisfy my curiosity about the antennas - the one wire that is not a trail of solder on the PCB is indeed firmly anchored to the PCB on one end and the antenna on the other.

All of the above and the radios on this router are still both putting out an un-usable signal.

I sat next to the router with a laptop and a wifi analytics program for a while and tracked the signal strength. Interestingly, the 5G radio stayed at a consistent weak signal, while the 2.4G radio was mostly weak (what the graph in the software called 30% signal) sitting 2 feet away from the router, but bounced up to an "excellent" "100%" signal every once in a while (irregular periods between bounces) which would last for 5 - 10 seconds before going back down to ~30-ish %.

 

[ktwetzel]

I ultimately ended up returning mine as I think the hardware was the issue. Got another TM-AC1900 and did the same flash procedure and it worked flawlessly. Now setup to run as an AIMesh node with my normal AC68u (originally on Merlin, but moved back to stock firmware for AIMesh setup).

 

[pjv]

I ultimately ended up returning mine as I think the hardware was the issue. Got another TM-AC1900 and did the same flash procedure and it worked flawlessly. Now setup to run as an AIMesh node with my normal AC68u (originally on Merlin, but moved back to stock firmware for AIMesh setup).

Wish I could do that - I'm sure you're right that it's just bad hardware. From when I bought it to when I finally had time start working on it, I used up the 30-day return window. I wrote the vendor, but I probably have either a very expensive 4-port switch or a very pretty paper weight with flashing blue lights.