Issues connecting RT-AC68P to modem

[Revolver]

I have a cable internet connection going to a Motorola SB6141 modem which then goes to an ASUS RT-AC68P router. Up until a few days ago the setup was working with no issues. With no changes being made, the router began to display "no WAN cable connected" when attempting to access the internet (via WiFi). I checked the router and the ethernet light was off.

Troubleshooting that was completed:
1. power cycled the router - no change
2. loaded the latest ASUS firmware - no change
3. loaded Asuswrt-Merlin firmware - no change
4. Changed ethernet cable (multiple cables) - no change
5. Tested the modem directly connected to PC, works normally.
6. Tested the router on my neighbors connection/modem - router appeared to be working properly.
7. Enabled "Dual Wan" over the LAN ports and tried connecting the modem through the LAN port - no change
8. Tested a different router on my modem, everything works properly.
9. Called my ISP, they were unable to see any reason on their side that it would not work, so they sent out a tech.
10. Tech came out, connected a "test modem" from the ISP, the router recognized being connected and began working (over WiFi)
11. Tried moving everything to a different power outlet - no change

At this point both the modem and router appear to be working interdependently when connected to other known good hardware, but will not work together.

I called ASUS, and they offered to RMA, but that could take several weeks to get the router back and I'm still unsure if there is anything wrong with the router.

Anyone have any ideas what the cause could be, or other troubleshooting steps?

Is there anything in the router system logs I should look for, or can I safely post those here?

Any help is greatly appreciated.

 

[jph1589]

You noted a number of times that your issue was when trying to access the internet (via Wifi) . Does that mean you could access the internet from a wired device attached to your router? Or did you just mean to stress that you dont have any wired connections? Just curious about that.

Also I keep looking at where you say that your router worked fine with the replacement cable modem the tech put on. That seems a little odd. I would be leaning toward the culprit being the cable modem.

 

[Revolver]

You noted a number of time that your issue was when trying to access the internet (via Wifi) . Does that mean you could access the internet from a wired device attached to your router?

No, I'm unable to access via wired devices either. I added the WiFi note since that's the only thing I had tried at the time, but I've since tried accessing over wired as well and the router doesn't recognize that anything is plugged in. I haven't tried wired connection with a a different modem yet. I'll need to take the router back to my neighbors to test that out since I don't have a spare modem.

 

[jph1589]

I edited my post above with some other notes. If everything worked when the tech put a different cable modem on your connection I'm gonna say that the cable modem has an issue.

 

[Revolver]

I edited my post above with some other notes. If everything worked when the tech put a different cable modem on your connection I'm gonna say that the cable modem has an issue.

If the modem wasn't working with any router, I would certainly agree. What throws me off is that I have installed a 2nd router on the modem and it is working with no issues.

 

[jph1589]

If the modem wasn't working with any router, I would certainly agree. What throws me off is that I have installed a 2nd router on the modem and it is working with no issues.

What was the model of that router that worked with no issues?

 

[Revolver]

What was the model of that router that worked with no issues?

An "on networks N300R"

 

[jph1589]

An "on networks N300R"

The first thing I notice is that N300R only has a 10/100 Wan port and your router has a 10/100/1000 Wan port. So your router is connecting to the modem at 1Gb and the one you tested only had to connect at 100Mb. That combined with the fact that your router worked fine on the test modem says to me it is the modem.

 

[Revolver]

The first thing I notice is that N300R only has a 10/100 Wan port and your router has a 10/100/1000 Wan port. So your router is connecting to the modem at 1Gb and the one you tested only had to connect at 100Mb. That combined with the fact that your router worked fine on the test modem says to me it is the modem.

I am able to connect 10/100/1000 devices directly to the modem and achieve ~200mbps, and the modem gives the correct lights for a 1Gb connection on these devices (where it doesn't on the N300R of course)

 

[jph1589]

I am able to connect 10/100/1000 devices directly to the modem and achieve ~200mbps, and the modem gives the correct lights for a 1Gb connection on these devices (where it doesn't on the N300R of course)

It is of course your call, but I would get a different modem from the ISP before I bought a new router or did an RMA on this one. If your router worked with the other modem the tech brought out, then I would give that a try.

 

[Revolver]

It is of course your call, but I would get a different modem from the ISP before I bought a new router or did an RMA on this one. If your router worked with the other modem the tech brought out, then I would give that a try.

Yeah, that's what I'm thinking at this point as well. I've reconnected the router at my neighbors (SB6121 modem), and it is able to connect and work via WiFi or wired (takes longer to connect than I would expect though). However, it only connects to the modem at 10/100 (evidenced by the link light staying orange instead of blue), when the modem does support 10/100/1000.

Another data point I've remembered from the tech is that when he installed the ISP modem on my router, the router connected and WiFi began working, but he was unable to connect his tablet via the LAN port. Though the LAN ports do seem to be working fine at my neighbors when connected to a laptop.

 

[jph1589]

Yeah, that's what I'm thinking at this point as well. I've reconnected the router at my neighbors (SB6121 modem), and it is able to connect and work via WiFi or wired (takes longer to connect than I would expect though). However, it only connects to the modem at 10/100 (evidenced by the link light staying orange instead of blue), when the modem does support 10/100/1000.

Another data point I've remembered from the tech is that when he installed the ISP modem on my router, the router connected and WiFi began working, but he was unable to connect his tablet via the LAN port. Though the LAN ports do seem to be working fine at my neighbors when connected to a laptop.

OK that additional data makes this a bit different. Go to Bestbuy and buy a different router and if it doesnt work they will take it back no questions. If it does work, RMA your other router and when you get the replacement, sell one of them.

 

[Revolver]

OK that additional data makes this a bit different. Go to Bestbuy and buy a different router and if it doesnt work they will take it back no questions. If it does work, RMA your other router and when you get the replacement, sell one of them.

Which bit of information changes it; that it was only connecting to the neighbors modem at 10/100, or that it did not connect to the ISP tech's tablet via cabled connection (looked like a Surface with a RJ-45 to USB adapter)?

Any ideas what could be the cause of it connecting to 2 other modems but not my own?

thanks for the help btw.

 

[jph1589]

Which bit of information changes it; that it was only connecting to the neighbors modem at 10/100, or that it did not connect to the ISP tech's tablet via cabled connection (looked like a Surface with a RJ-45 to USB adapter)?

Any ideas what could be the cause of it connecting to 2 other modems but not my own?

thanks for the help btw.

It's not connecting properly to your neighbors modem. As you said it didn't connect at 1Gb. Also you said that the tech couldnt connect on your ethernet port. I didn't know those things when I said replace the modem.

You are making sure you are using good Cat 6 ethernet cables for all wired connections including the cable modem, right?

 

[Revolver]

It's not connecting properly to your neighbors modem. As you said it didn't connect at 1Gb. Also you said that the tech couldnt connect on your ethernet port. I didn't know those things when I said replace the modem.

You are making sure you are using good Cat 6 ethernet cables for all wired connections including the cable modem, right?

They are Cat 5E cables.

I suppose I'll just keep using the onnetwork router and send the Asus for RMA. Although, I'm kinda worried they will just send it back to me in a few weeks stating that nothing's wrong with it.

If I went and picked up a gigabit capable router, and it worked properly, do you think that would effectively eliminate the modem as a potential source of the problem?

 

[jph1589]

If I went and picked up a gigabit capable router, and it worked properly, do you think that would effectively eliminate the modem as a potential source of the problem?

Yes

 

[Revolver]

Yes

Ok, I've purchased a Linksys EA6350. The modem gave a blue link light as soon as the router was plugged in. During initial setup of the router, following it's version of a 'setup wizard' the router stated repeatedly that it "could not verify your connection to the internet". I selected to skip the automatic setup and went through it manually, leaving everything at the default. It is now working via LAN and WiFi with a gigabit connection to the modem.

When I go to send in the Asus router, are there any steps I should take to clear any personal information from it other than returning it to the Asus firmware and factory restore?

 

[sfx2000]

I have a cable internet connection going to a Motorola SB6141 modem which then goes to an ASUS RT-AC68P router. Up until a few days ago the setup was working with no issues. With no changes being made, the router began to display "no WAN cable connected" when attempting to access the internet (via WiFi). I checked the router and the ethernet light was off.

It's your modem - and there, most likely the power supply for the modem itself - replace it, and you'll likely be right as rain...

The SB6141 is a great modem, but the power supply/ac adapter is very poor quality - it'll be good for a couple of years under constant use, but it does fail eventually with symptoms like this...

 

[TonyH]

Which bit of information changes it; that it was only connecting to the neighbors modem at 10/100, or that it did not connect to the ISP tech's tablet via cabled connection (looked like a Surface with a RJ-45 to USB adapter)?

Any ideas what could be the cause of it connecting to 2 other modems but not my own?

thanks for the help btw.

Are you doing all this testing with one only desk top or laptop? Tried some other one? Did you turn off modem and computer, wait few minutes, the power up one after another? Any difference? What is your NIC in the computer, by any chance an Intel one? Then you can run diagnostics when download Proset from Intel.

 

[Revolver]

It's your modem - and there, most likely the power supply for the modem itself - replace it, and you'll likely be right as rain...

The SB6141 is a great modem, but the power supply/ac adapter is very poor quality - it'll be good for a couple of years under constant use, but it does fail eventually with symptoms like this...

I did try a new ac adapter, but unfortunately it did not make any difference.

Are you doing all this testing with one only desk top or laptop? Tried some other one? Did you turn off modem and computer, wait few minutes, the power up one after another? Any difference? What is your NIC in the computer, by any chance an Intel one? Then you can run diagnostics when download Proset from Intel.

2 different laptops and 2 desktops with wireless NIC's. I did power off modem and computer, waited and powered on in sequence, but it made no difference.

I'm planning to ship in the Asus in the morning. Once I get it back I'll follow-up here with the findings/results of the RMA. Thanks for everyone's help.