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CGN3 keeps rebooting itself

dperron
I'm Here A Lot

So, intermittently, my CGN3 modem will reboot itself. All the lights, except the power light, shut off and it takes about 3 minutes to come back up. This evening, this happened about 5 or 6 times in the span of 90 minutes. This issue had occured to me before and after speaking with a Rogers tech, the modem was exchanged and no issues were had for about 3 weeks, until this evening. What are the odds of 2 defective modems? The last time this happened, a tech ended up coming after I replaced the modem and tested the signal and said it was very good.

 

I spoke with tech support again this evening and they're sending another tech but I am skeptical that they'll find anything wrong. Any ideas?

 

***Edited Labels***

1 ACCEPTED SOLUTION

Accepted Solutions

Re: CGN3 keeps rebooting itself

Fabian14
I've Been Here Awhile

Hello,

The issue appears to be solved. A technician was sent home, who concluded that there probable was too much noise in the cable feeding the modem. He changed the cable feeding the modem, and the problem appears to have been solved with that.

Thank you!

 

View solution in original post

59 REPLIES 59

Re: CGN3 keeps rebooting itself

Datalink
Resident Expert
Resident Expert

My guess would be that the modem is rebooting in order to regain comms with the neighborhood node.  One modem failure, okay, two, not okay, three, you should be buying lottery tickets.  Can you log into the modem, navigate to the STATUS.... DOCSIS WAN page, copy the downstream and upstream tables and paste them into this thread. Those tables are the RG-6 signal levels which should be of interest at the present time.



Re: CGN3 keeps rebooting itself

Thanks for responding. Here are the tables.

 

Downstream Overview
Port IDFrequency (MHz)ModulationSignal strength (dBmV)Channel IDSignal noise ratio (dB)
1621000000256QAM3.500438.605
2591000000256QAM5.1001238.605
3597000000256QAM4.6001338.983
4603000000256QAM4.000138.605
5609000000256QAM4.500238.605
6615000000256QAM4.400338.605
7633000000256QAM4.400538.983
8639000000256QAM3.900638.983
9645000000256QAM3.400738.605
10651000000256QAM4.100838.605
11657000000256QAM4.400938.605
12663000000256QAM3.8001038.605
13669000000256QAM3.8001138.605
14675000000256QAM4.4001438.605
15681000000256QAM5.4001538.605
16687000000256QAM5.1001638.605
17693000000256QAM5.6001738.983
18699000000256QAM5.7001838.605
19705000000256QAM5.3001938.983
20711000000256QAM5.7002038.605
Upstream Overview
Port IDFrequency (MHz)ModulationSignal strength (dBmV)Channel IDBandWidth
130596000ATDMA - 64QAM42.00026400000
223700000ATDMA - 64QAM42.00036400000
338596000ATDMA - 64QAM42.50013200000

Re: CGN3 keeps rebooting itself

Those signal levels and signal to noise ratios look fine.  Only thing I can think of in relation to those levels would be a rapid loss and regain of the cable signals, which might cause the modem to initiate a reboot, but at this time they're fine.   If there was a rapid spike down, I doubt that you would be able to catch it, but, if this does happen again, see if you can log in fast enough after the reboot and have a look at the signal levels to see if there are any big differences.  Are you in a house, and if so, is the external cable leading to the house arriving overhead from a utility pole, or underground from the local tap?

 

Do you run your equipment from a power bar, and if so, have you tried to run everything with the power bar completely disconnected to determine if the power bar itself is causing the issue.

 

Can you check the power adapter for the modem and see if it is hot to the touch.  It should only be slightly warm. 

 

When you replaced the modem, did you replace the power adapter as well?

 

Is the modem standing upright and is it in a location where it will stay cool, ie, not located within a cabinet.

 

 



Re: CGN3 keeps rebooting itself

I have seen something similar - @Datalink touched on it - does your power adapter (running from the modem to wall) feel warm to the touch?

 

Try plugging it into a different outlet, or different power bar if possible.

 

In my case, replacing my power bar fixed the issue (it was overloaded and very old, purchased a 12-port Belkin from Amazon.ca and smooth sailing since).

Re: CGN3 keeps rebooting itself

Thank you for answering. I'll try to provide answers for all the scenarios you put forward.

 

I live in a house and as far as I know the cable comes from a post outside. When they installed it in October, the tech said that he had to install it from scratch because the job had been botched before. 

 

When I exchanged the modem, I also exchanged the power supply. The modem sits vertically and was plugged directly in the wall. However, the plug was located behind a couch, perhaps limiting its ability to cool off (although it wasn't hot when I touched it). The modem was also located under a surround sound speaker, and I've read people say that perhaps that could cause interference.

 

This morning, I moved the modem to the floor, away from the speaker, and have it plugged directly in the wall, unobstructed. I suppose we'll have to see if that resolves the issue.

 

Fingers crossed!

 

 

Re: CGN3 keeps rebooting itself

dperron
I'm Here A Lot
It did it again tonight, even after relocating the modem. I'm out of ideas.

Re: CGN3 keeps rebooting itself

Were you able to log into the modem and see if there was anything unusual about the signal levels?

 

Next step is to isolate the inputs and outputs.   When you look at the modem, there isn't that much that can go wrong, power, ethernet connected devices and cable input. 

 

1.  If you happen to have an extension cord available, I'd use that to plug the modem into a different house electrical circuit.  Run that as a test configuration, looking for a failure.

2.  If you do have a failure, its not a power issue.  In that case, if you have ethernet connected devices, you can either disconnect them as a group altogether, or disconnect them one at a time, looking for a failure after each disconnect.  This might take a few days to work thru. 

3.  Final step would be to disconnect the wifi devices, one network at a time, but first, have a look for power or ethernet caused failures.

 

We have seen what appear to be failures with both CGN3 and CGN3ACSMR.  However, stepping thru a test program has revealed the cause to be a failing ethernet or wifi adapter on the connected device.  However, we haven't seen a reboot occur in all of this, so this is a little unusual.  So, have a go at this to see what happens. 



Re: CGN3 keeps rebooting itself

dperron
I'm Here A Lot

1. I'm not sure I have an extension cord long enough to get to a different room but if I find one I'll try.
2. I have no Ethernet devices connected.
3. You're saying it's possible that one of the clients is making this modem reboot?

By the way, if I look at DOCSIS Event after a crash, there's always this error:
Type: 90000000
Priority: warning
Event: MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=00;CMTS-MAC=00;CM-QOS=1.1;CM-VER=3.0;

Does that help?

Re: CGN3 keeps rebooting itself

dperron
I'm Here A Lot
A tech came in Sunday and tested the connections everywhere, with good results. He did replace a connector outside that he said was loose and could cause the issue I was having. So far so good...

Re: CGN3 keeps rebooting itself

Fabian14
I've Been Here Awhile

I'm having issues of lossing my internet connection a few times per week. The software version is 4.5.8.16. I've pasted the DOCSIS WAN table and Software Version below. The Harware Version is 1A. Does anyone have any suggestion? Thank you in advance!

 

Downstream Overview
Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID Signal noise ratio (dB)
1 657000000 256QAM 0.700 131 38.983
2 591000000 256QAM 2.200 121 38.983
3 597000000 256QAM 2.400 122 38.983
4 603000000 256QAM 2.500 123 38.983
5 609000000 256QAM 2.200 124 38.983
6 615000000 256QAM 1.900 125 38.605
7 621000000 256QAM 1.700 126 38.983
8 633000000 256QAM 1.400 127 38.605
9 639000000 256QAM 1.200 128 38.983
10 645000000 256QAM 0.800 129 38.983
11 651000000 256QAM 0.600 130 38.983
12 663000000 256QAM 0.800 132 38.605
13 669000000 256QAM 0.400 133 38.605
14 675000000 256QAM 0.400 134 38.605
15 681000000 256QAM 0.600 135 38.605
16 687000000 256QAM 0.600 136 38.605
17 693000000 256QAM 0.600 137 38.605
18 699000000 256QAM 0.800 138 38.983
19 705000000 256QAM 1.100 139 38.983
20 711000000 256QAM 1.200 140 38.605
Upstream Overview
Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID BandWidth
1 30596000 ATDMA - 64QAM 38.500 2 6400000
2 23700000 ATDMA - 64QAM 38.750 3 6400000
3 38596000 ATDMA - 64QAM 38.500 1 3200000
Software Version

4.5.8.16

Re: CGN3 keeps rebooting itself

Hello @Fabian14,

 

Welcome to the Community!

 

Can you please explain what issues you are having with your Internet service? Do you have more than one device and are you connected via WiFi? When you say you are losing connection, are you referring to your modem disconnecting altogether or just losing WiFi connectivity? Have you spoken to tech support already and gone through standard troubleshooting? Please provide more details. @Datalink, please feel free to chime in. 

 

Thanks, 

RogersHassam 

Re: CGN3 keeps rebooting itself

The signal levels and signal to noise ratios all look good.  If there is something going on, signal wise, its not showing up in that data set.  If you could provide a few more details as to what happens when you lose connectivity, that would help.  Is that for both ethernet and wifi connected devices?  Does the modem reboot or keep running?  And, what do you do to solve the situation?



Re: CGN3 keeps rebooting itself

Fabian14
I've Been Here Awhile

Hello,

The issue appears to be solved. A technician was sent home, who concluded that there probable was too much noise in the cable feeding the modem. He changed the cable feeding the modem, and the problem appears to have been solved with that.

Thank you!

 

Re: CGN3 keeps rebooting itself

Ah, ok.  In that case, your ethernet speedtest results should be above your internet plan, with Rogers speedboost kicking in.  Try running an ethernet connected speedtest at http://speedcheck.rogers.com/en.html or the www.speedtest.net Toronto Telus server, just to ensure that everything has gone according to plan. 



Re: CGN3 keeps rebooting itself

Fabian14
I've Been Here Awhile

When I had the issue, the modem kept running until I rebooted it manually. All connected devices lost the internet connection. It has been working properly since the cable feed was changed.

Thank you!

Re: CGN3 keeps rebooting itself

@Fabian14, Glad the issue is resolved. Thanks for the update. 

 

@Datalink, Thanks for jumping in as always 🙂

 

RogersHassam 

Re: CGN3 keeps rebooting itself

DiannaQ1
I've Been Here Awhile

Sorry to bring up an old forum post, but I am in need of some help. For the past few months, I've had very unconsistant internet connection with my CGN3ACSMR modem. Tried replacing it with another twice, maybe three times but always get the same results. It happens at very random times but the modem will drop connection and then begin a restart on itself.

 

Here's an example. Last night I was streaming the Jays game (go Jays go) for a few innings, and then the stream stopped. I looked at the modem and within 5-10 seconds the UL, DL and @ symbols on the modem disappear but both 2.4G and 5G wifi connections stay running. Until the modem resets itself, I am basically connected to the modem with no internet connection. I've had several Techs come to my house and the results are always the same: everything appears fine on their end when they are at my house. The latest Tech that came to my house said the connection coming in the house seems fine. The modem is in my bedroom on a stand, nowhere near a TV or the sort that would cause distortion. I've tried moving the modem to another room, plugging in a different outlet but can't figure out what is causing this random connection drop. I'm starting to think maybe it's one of my devices but I hope someone can chime in here to help. 

 

Software version is 4.5.8.22

 

Downstream Overview
Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID Signal noise ratio (dB)
1 663000000 256QAM 2.000 25 38.983
2 561000000 256QAM 1.800 9 40.366
3 567000000 256QAM 1.800 10 40.366
4 573000000 256QAM 1.900 11 40.366
5 579000000 256QAM 2.300 12 40.366
6 585000000 256QAM 2.200 13 40.366
7 591000000 256QAM 2.000 14 40.366
8 597000000 256QAM 2.500 15 40.946
9 603000000 256QAM 2.100 16 40.366
10 609000000 256QAM 2.500 17 40.946
11 615000000 256QAM 2.000 18 40.366
12 621000000 256QAM 1.400 19 40.366
13 633000000 256QAM 2.300 20 40.366
14 639000000 256QAM 2.200 21 38.983
15 645000000 256QAM 1.500 22 40.366
16 651000000 256QAM 1.300 23 38.983
17 657000000 256QAM 2.100 24 40.366
18 555000000 256QAM 1.500 40 40.946
19 669000000 256QAM 2.300 26 38.983
20 675000000 256QAM 3.200 27 40.946
21 681000000 256QAM 3.100 28 40.366
22 687000000 256QAM 3.400 29 40.366
23 693000000 256QAM 3.600 30 40.366
24 699000000 256QAM 4.000 31 40.366
Upstream Overview
Port ID Frequency (MHz) Modulation Signal strength (dBmV) Channel ID BandWidth
1 38596195 ATDMA - 64QAM 43.750 3 3200000
2 30596000 ATDMA - 64QAM 43.750 1 6400000
3 23700000 ATDMA - 64QAM 43.750 2 6400000

 



 

Re: CGN3 keeps rebooting itself

 

Hello, @DiannaQ1

 

Welcome to the Rogers Community Forums! Smiley Happy

 

Thank you for posting your concern in the Community. I appreciate all the details of your post. Both the Downstream and Upstream signal levels at your modem are good. So we can rule out the signal as the potential cause of the reboot. We have seen quite a few times in our forum a local network device causing the modem to reboot. Do you have a USB WiFi adapter in use on your network?

 

Cheers,

RogersMoin

Re: CGN3 keeps rebooting itself

DiannaQ1
I've Been Here Awhile

I figured it out.

 

Assuming it was one of my devices, I disabled wifi on them one-by-one but the problem was still persisting. My next thought was my cabling coming into the house (since the last tech that came over said the signal coming in was fine). Looked around the outside of my house and everything looked fine from what I could tell. I looked in my breaker panel box, saw the cable coming from the outside of the house runs into a splitter (which seemed old). Replaced the splitter and voila!

 

Thanks for helping

Re: CGN3 keeps rebooting itself

DiannaQ1
I've Been Here Awhile

Yeah.. so I take it back. After a good 36-48hr run it's back at it again. Random disconnects during random times. I logged into the modem and from what I could read and understand it lost connection a few times during the day while I was at work. This is in my DOCSIS Log from the most recent disconnect:

- Edited log as it contains modem's MAC address - RogersMoin

 

And @RogersMoin I don't have any USB Wifi devices on our network at home

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