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SoCalLV's avatar
SoCalLV
Aspirant
Dec 28, 2025

CM1000 w/ R7000P

Hi    I’ve had my modem and router for a couple of years. Everything was working fine till couple months ago my internet has been buggy.  I noticed the modem upstream light will blink green then st...
CM1000
FURRYe38's avatar
FURRYe38
Guru - Experienced User
Jan 06, 2026

Can we get the Event Logs page data as well. 

 

Power for some of our channels is too much and too high. 

https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router

 

I'd day get a -3 or -6dbm cable coax line attenuator installed. 

 

SoCalLV wrote:

11 Locked QAM256 11 795000000 Hz 8.9 dBmV 42.7 dB 86892372 0 0
12 Locked QAM256 12 801000000 Hz 9.0 dBmV 42.7 dB 86899213 0 0
13 Locked QAM256 13 807000000 Hz 9.1 dBmV 42.7 dB 86906720 0 0
14 Locked QAM256 14 813000000 Hz 9.2 dBmV 42.7 dB 86914866 0 0
15 Locked QAM256 15 819000000 Hz 9.1 dBmV 42.8 dB 86922259 0 0
16 Locked QAM256 16 825000000 Hz 9.1 dBmV 42.8 dB 86929503 0 0
17 Locked QAM256 17 831000000 Hz 9.1 dBmV 42.7 dB 86937175 0 0
18 Locked QAM256 18 837000000 Hz 9.1 dBmV 42.7 dB 86944389 0 0
19 Locked QAM256 19 843000000 Hz 9.4 dBmV 42.9 dB 86952100 0 0

 

SoCalLV's avatar
SoCalLV
Aspirant
Jan 06, 2026

Here you go. Seeing a lot of critical.

The coax line attenuator is that something I need to connect my ISP or can I do it myself. Where would I replace the attenuator?

2026-01-06, 21:13:22Critical (3)SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
2026-01-06, 21:12:34Notice (6)US profile assignment change. US Chan ID: 6; Previous Profile: 13; New Profile: 9 13.;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
2026-01-06, 21:11:41Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
2026-01-06, 21:11:39Warning (5)Dynamic Range Window violation
2026-01-06, 21:11:39Warning (5)RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
2026-01-06, 21:11:39Warning (5)Dynamic Range Window violation
2026-01-06, 21:11:39Warning (5)RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
2026-01-06, 21:11:38Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
2026-01-06, 21:11:32Notice (6)DS profile assignment change. DS Chan ID: 33; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
2026-01-06, 21:11:30Notice (6)DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
2026-01-06, 21:11:25Notice (6)TLV-11 - unrecognized OID;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
Time Not EstablishedWarning (5)DHCP WARNING - Non-critical field invalid in response ;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
  • SoCalLV's avatar
    SoCalLV
    Aspirant
    Jan 06, 2026
    2026-01-06, 21:07:11Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
    Time Not EstablishedCritical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    2026-01-06, 21:02:09Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
    2026-01-06, 21:02:05Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
    2026-01-06, 21:02:05Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
    Time Not EstablishedCritical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
    2026-01-06, 20:58:49Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
    2026-01-06, 20:58:49Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
    • SoCalLV's avatar
      SoCalLV
      Aspirant
      Jan 06, 2026
      Time Not EstablishedCritical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
      Time Not EstablishedCritical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
      2026-01-06, 20:54:15Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
      2026-01-06, 20:54:11Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
      2026-01-06, 20:54:11Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
      Time Not EstablishedCritical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
      2026-01-06, 20:49:49Critical (3)SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
      2026-01-06, 20:48:07Critical (3)No Ranging Response received - T3 time-out;CM-MAC=c8:9e:43:72:2f:60;CMTS-MAC=04:76:b0:24:4c:ef;CM-QOS=1.1;CM-VER=3.1;
  • FURRYe38's avatar
    FURRYe38
    Guru - Experienced User
    Jan 07, 2026

    SoCalLV​ 

     

    Any Criticals, Errors or Warnings seen in the event logs needs to be reviewed and resolved by the ISP. Indicates a signal issue on the ISP line up to the modem.

     

    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. 

    Start with removing any amplifiers, signal attenuators, or splitters from the coax.

    From there check the line for kinks, damage, moisture in the line.

    Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.

    Be sure to power OFF the modem for 1 minute then back ON.

    https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Modems/m-p/1530376#M12853

    https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router

    https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

    https://highspeed.tips/docsis-events/

     

    • SoCalLV's avatar
      SoCalLV
      Aspirant
      Jan 07, 2026

      I called my ISP, they are coming tomorrow. I’ll follow up.

      • FURRYe38's avatar
        FURRYe38
        Guru - Experienced User
        Jan 07, 2026

        👍