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WaveWarper's avatar
WaveWarper
Aspirant
Jan 12, 2021

CM1200 Modem Upstream LED Flashing - Spectrum Internet

I've had this modem for just over a year and it started dropping signal a couple days ago. The upstream LED was flashing green so I had a tech from Spectrum come out and check on everything. They promptly swapped my CM1200 out for one of their modems and everything worked. This is really frustrating considering I paid around $200 for the modem.

Any ideas what could be causing the issue and why the tech couldn't find a solution? Should I have "Enable Extended Upstream Transmit Power" checked in the modem options?

Hardware Version1.01
Firmware VersionV1.02.01
CM CertificateInstalled

 

I'm getting a bunch of errors and warnings in the log like this when connecting the modem:

 

Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out
Critical (3)16 consecutive T3 timeouts while trying to range on upstream channel 8
Warning (5)Dynamic Range Window violation
Warning (5)RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW
Error (4)Missing BP Configuration Setting TLV Type

13 Replies

  • plemans's avatar
    plemans
    Guru
    Jan 12, 2021

    The full logs as well as the cable connection page helps. 

    Take a screen snip of them and post them here. 

  • FURRYe38's avatar
    FURRYe38
    Guru
    Jan 12, 2021

    Please post the Connection status page that gives the power levels seen on each channel.

    Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
    Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
    Be sure your using good quality RG6 coax cable up to the modem. 
    Be sure to power OFF the modem for 1 minute them back ON.
    https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Modems/m-p/1530376#M12853

      • FURRYe38's avatar
        FURRYe38
        Guru
        Jan 12, 2021

        You would need to check to be sure. 

         

        Your power levels seems a bit high...

        Heres mine:

        Startup Procedure
        ProcedureStatusComment
        Acquire Downstream Channel837000000 HzLocked
        Connectivity StateOKOperational
        Boot StateOKOperational
        SecurityEnabledBPI+
        IP Provisioning ModeHonor MDDhonorMdd(4)
         
        Downstream Bonded Channels
        ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
        1LockedQAM25631837000000 Hz-2.5 dBmV37 dB00
        2LockedQAM2561651000000 Hz-2.5 dBmV36.4 dB00
        3LockedQAM2562657000000 Hz-2.6 dBmV36.4 dB00
        4LockedQAM2563663000000 Hz-2.3 dBmV36.6 dB00
        5LockedQAM2564669000000 Hz-2.3 dBmV36.6 dB00
        6LockedQAM2565675000000 Hz-2.1 dBmV36.7 dB00
        7LockedQAM2566681000000 Hz-2 dBmV36.9 dB00
        8LockedQAM2567687000000 Hz-1.8 dBmV36.8 dB00
        9LockedQAM2568693000000 Hz-1.7 dBmV36.9 dB00
        10LockedQAM2569699000000 Hz-1.5 dBmV37 dB00
        11LockedQAM25610705000000 Hz-1.5 dBmV36.8 dB00
        12LockedQAM25611711000000 Hz-1.3 dBmV36.9 dB00
        13LockedQAM25612717000000 Hz-0.8 dBmV37.1 dB00
        14LockedQAM25613723000000 Hz-1 dBmV36.9 dB00
        15LockedQAM25614729000000 Hz-0.7 dBmV36.9 dB00
        16LockedQAM25616741000000 Hz-0.6 dBmV37.1 dB00
        17LockedQAM25617753000000 Hz-0.7 dBmV37.2 dB00
        18LockedQAM25618759000000 Hz-0.9 dBmV37.1 dB00
        19LockedQAM25619765000000 Hz-1.3 dBmV37.1 dB00
        20LockedQAM25620771000000 Hz-1.3 dBmV37.2 dB00
        21LockedQAM25621777000000 Hz-1.5 dBmV37.3 dB00
        22LockedQAM25622783000000 Hz-1.7 dBmV37.3 dB00
        23LockedQAM25623789000000 Hz-1.7 dBmV37.4 dB00
        24LockedQAM25624795000000 Hz-1.9 dBmV37.3 dB00
        25LockedQAM25625801000000 Hz-2.1 dBmV37.1 dB00
        26LockedQAM25626807000000 Hz-2 dBmV37.2 dB00
        27LockedQAM25627813000000 Hz-2 dBmV37.2 dB00
        28LockedQAM25628819000000 Hz-2.4 dBmV36.9 dB00
        29LockedQAM25629825000000 Hz-2.3 dBmV37.2 dB00
        30LockedQAM25630831000000 Hz-2.3 dBmV37.1 dB00
        31LockedQAM25632843000000 Hz-2.5 dBmV37 dB00
        32Not LockedUnknown00 Hz0.0 dBmV0.0 dB00
         
        Upstream Bonded Channels
        ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
        1LockedATDMA15120 Ksym/sec36000000 Hz38.8 dBmV
        2LockedATDMA25120 Ksym/sec29000000 Hz37.5 dBmV
        3LockedATDMA55120 Ksym/sec22000000 Hz38 dBmV
        4LockedATDMA62560 Ksym/sec16000000 Hz37 dBmV
        5Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
        6Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
        7Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
        8Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
         
        Downstream OFDM Channels
        ChannelLock
        Status        		Modulation /
        Profile ID        		Channel
        ID        		FrequencyPowerSNR /
        MER        		Active Subcarrier
        Number Range        		Unerrored
        Codewords        		Correctable
        Codewords        		Uncorrectable
        Codewords
        1Locked0 ,1 ,233547000000 Hz-4.0 dBmV36.5 dB1108 ~ 2987107438938876128590
        2Not Locked000 Hz0 dBmV0.0 dB0 ~ 4095000