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?
Solved! Solved! Go to Solution.
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.
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.
Thanks for responding. Here are the tables.
|Port ID||Frequency (MHz)||Modulation||Signal strength (dBmV)||Channel ID||Signal noise ratio (dB)|
|Port ID||Frequency (MHz)||Modulation||Signal strength (dBmV)||Channel ID||BandWidth|
|1||30596000||ATDMA - 64QAM||42.000||2||6400000|
|2||23700000||ATDMA - 64QAM||42.000||3||6400000|
|3||38596000||ATDMA - 64QAM||42.500||1||3200000|
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.
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).
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.
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.
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:
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?