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Netgear CM1200 and error log question

Miller541Miller541 Posts: 10 Spectator
edited September 14 in Connectivity Jul 09, 2022


I have a Netgear CM1200 that is showing some odd logs. I keep getting drops in connection about once a week if not more.

I notice that the time on the modem is off by 1 hour, so it's not getting time sync from ntp I guess. I also see that Spectrum has decommissioned it's NTP servers via a comment in the FAQ section.

I use OPNsense as my router.. does anyone have any config prefs for Spectrum?

Here are some logs to chew on..

Best Answer

  • William_MWilliam_M Posts: 454 Moderator
    Jul 23, 2022 Answer ✓

    An occasional error by itself is not cause for concern. Many things can cause interference or signal fluctuations, but there is a range where the signals can be without causing too many problems and built in error correction to compensate. Please let us know if you actually lose service or have other problems with the internet and we will be happy to investigate further.


  • William_MWilliam_M Posts: 454 Moderator
    Jul 10, 2022

    Hi @Miller541, welcome to our community!

    Looking at your modem from our end I do see it went offline for about an hour on 07/09 which explains the errors you got, but currently the connection looks healthy.

    I recommend making sure the coaxial cable is firmly connected to the modem and wall outlet. I will also set up our system to more closely monitor the connection to the modem for the next two weeks. Please let us know if you lose service again so we can check our logs and determine the best course of action to see this issue resolved.

  • RAIST5150RAIST5150 Posts: 873 Contributor
    Jul 10, 2022

    Oof... -12.5 or worse downstream, 52.5 upstream levels.

    Not a lot of wiggle room for correction before a forced reboot when temperature shifts and other factors that can impair signal quality show up.

    May need to inspect your cable runs for damage, loose/corroded fittings, poor grounds, standing water/hot spots, etc.

  • Miller541Miller541 Posts: 10 Spectator
    edited July 10 Jul 10, 2022

    It was at -10 on downstream until a new neighbor got added to the node, roughly about 2 weeks ago.

    All connections are tight. About 50% or more of my cable run is underground.. ran by Charter back in the day before it became Spectrum, no way to inspect that part. The PED they attach to has been kicked several times by installers to get the cover off, cable pinching under the PED as its been swapped back and forth between another city owned PED nearby a few times before I moved in, so I dont know the true condition of the cable at that end.

    I will be swapping rooms today, so connection will get better, I hope.

    Thank you for running a monitor at the NOC. Interested to see what it tells us.

  • karlbeckmankarlbeckman Posts: 2,284 Contributor
    Jul 11, 2022

    Signal levels both up and down are about 3 dBmV off from the normal system warning triggers. I'll bet the problem is visible at the pedestal and trouble could be in the buried service line or further out on the trunk.

  • Miller541Miller541 Posts: 10 Spectator
    Jul 12, 2022

    New levels after some cleanup, regrounding, etc... found that the installer had tapped the -7db term on a splitter instead of the -3db.

    Modem is currently flashing it's downstream icon, meaning it's scanning for a downstream channel even tho all look locked in to me.

    Let me know if these levels look better please.

    Also can you post a 24 hour graph of power level and noise please?

    Thanks a bunch!

  • Miller541Miller541 Posts: 10 Spectator
    Jul 19, 2022

    New disconnect today..

  • William_MWilliam_M Posts: 454 Moderator
    Jul 20, 2022

    Anywhere from -14 to 14 dBmv Downstream is acceptable, and 25 to 55 Upstream. I'm just seeing your log shows one timeout, but on 7/15 I show your modem was offline for almost 6 hours and I am seeing some spikes in upstream CCER. I recommend scheduling an appointment with a technician to test the lines, I will send you a private message from our @Community_Help handle to get your information if you would like to set that up. You can see private messages by selecting the envelope in the top right hand corner.

  • Miller541Miller541 Posts: 10 Spectator
    edited July 22 Jul 22, 2022

    Tech came out, made a couple alterations.

    Had this in my CM logs this morning, day after the visit.

    Fri Jul 22 01:54:39 2022Warning (5)RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=28:80:88:b1:ce:d0;CMTS-MAC=00:01:5c:67:d0:4c;CM-QOS=1.1;CM-VER=3.1;

    Fri Jul 22 01:54:35 2022Critical (3)SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=28:80:88:b1:ce:d0;CMTS-MAC=00:01:5c:67:d0:4c;CM-QOS=1.1;CM-VER=3.1;

    Are the graphs showing improvments?

    Tech said the PED might need replacing.

    Thanks again for all your help.

  • Paul_BPaul_B Posts: 577 Moderator
    Jul 22, 2022

    Hello @Miller541

    I took a look at your modem and it looks like over the last 24 hours or so, the modem has good signals and I am not seeing any drops in connection. Are you seeing any drops on your side at all?

    Thank you.


  • Miller541Miller541 Posts: 10 Spectator
    Jul 22, 2022

    Only the drops in the logs above. I dont think I lost sync tho, as no lights were flashing on the modem.

  • Paul_BPaul_B Posts: 577 Moderator
    Jul 23, 2022

    You may see random entries like this occasionally in the logs and are generally not a cause for concern. The main things we look for are the Loss of Sync, T3 and T4 time outs on a large or more frequent scale. If you notice that the connection degrades or gets worse, please let us know here so we can further troubleshoot to find out what may be happening.

    Thank you.


  • Miller541Miller541 Posts: 10 Spectator
    Aug 06, 2022

    Still have that graph up on my modem?

    Had another loss of sync it seems.

    I have the number for the local supervisor given to me by the last tech that was out, let me know if I should contact him.

    Everything looks fine to me, let me know if you see something that I don't.

  • William_MWilliam_M Posts: 454 Moderator
    Aug 06, 2022

    I'm not seeing any drops from my end. Do you lose service on all devices at the same time, including devices connected with ethernet cables? Any changes to the lights on the modem or router? How long does it go down for before coming back on?

  • Miller541Miller541 Posts: 10 Spectator
    Aug 06, 2022

    It went down while I was at work. I'm not sure for how long. Downstream light is blinking. Seems it cant even go 1 day without the downstream light blinking before I have to reboot to get it to stop.

    I will just keep an eye on it for now I guess.


  • William_MWilliam_M Posts: 454 Moderator
    Aug 06, 2022

    You're welcome!

  • ChadConChadCon Posts: 1 Newcomer
    Aug 13, 2022

    Hate to jump on this thread, but I have the same modem, but am having constant error log issues. I assume it relates to my firmware being out-of-date and my area's implementation of OFDMA (this is my second go-around with this issue as I solved it previously by downgrading to a slower modem - the Netgear CM500).

    End result of the errors is an intermittent connection and much slower service than my CM500.

    According to Netgear, my CM1200 should be running v3.02.01, but instead it's stuck on V1.02.01.

    Any suggestions on forcing a firmware update? Any other help?

    See below:

    And here's what my connection looks like:

  • Renee_TRenee_T Posts: 390 Moderator
    Aug 14, 2022

    Hello @ChadCon!

    Welcome to our community! As the modem firmware does have to be fully tested and approved for our network before it can be rolled out to customers, we don't have a way of manually forcing them. As soon as they are approved, they would be rolled out automatically.

  • Miller541Miller541 Posts: 10 Spectator
    edited August 14 Aug 14, 2022


    I'd try a factory reset on the CM1200 instead of a reboot. Does it even connect? It's true Charter presses the firmware updates from their side.

    My info is:

    Hardware Version 1.01

    Firmware Version V3.02.01

    Southern Oregon Spectrum Connection

This discussion has been closed.