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Nightly Modem Disconnects - 😡

lilminxlilminx Posts: 25
in Connectivity Jun 15, 2020
Nightly modem disconnects that triggers every device in the house to lose internet connection - wired and wireless.
We’ve had 4 Techs out in the past year and no one can fix.
We have T4 and T3 timeouts every day and night.
Every Tech comes in to our home and rewires and either removes splitter or replaces splitter band caps unused splitter. There is actually 1 line that goes directly to modem. We do not split for cable as we are internet-only household (no phone no cable box).
Our downstream snr has been at the 40.8 to 41.3 and upstream at 43.8.
Logs CONSISTENTLY show this:

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=20:3d:66:8e:xx:xxCMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:8e:xx:xx;CMTS-MAC=00:17:10:87:10:04;CM-QOS=1.1;CM-VER=3.0;

SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=20:3d:66:8e:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=20:3d:66:8e:xx:xx;CMTS-MAC=00:17:10:87:10:04;CM-QOS=1.1;CM-VER=3.0;

TLV-11 - unrecognized OID;CM-MAC=20:3d:66:8e:xx:xx;CMTS-MAC=00:17:10:87:10:04;CM-QOS=1.1;CM-VER=3.0;

Missing BP Configuration Setting TLV Type: 17.9;CM-MAC=20:3d:66:8e:xx:xx;CMTS-MAC=00:17:10:87:10:04;CM-QOS=1.1;CM-VER=3.0;

Missing BP Configuration Setting TLV Type: 17.8;CM-MAC=20:3d:66:8e:xx:xx;CMTS-MAC=00:17:10:87:10:04;CM-QOS=1.1;CM-VER=3.0;

Anyone know what the problem is? We are having trouble finding a Tech at Spectrum that can identify the problem and fix it.

Help of ANY sort would be greatly appreciated. We are desperate for answers as this issue has been plaguing us for years now and no fix.


  • RAIST5150RAIST5150 Posts: 646 ✭✭✭✭
    Jun 15, 2020
    How do the downstream signal levels look, and what modem is in play?

    Some modems are more sensitive than others, but generally if the db levels are falling outside of -8 to +10 that could be what is triggering it.

    Alternatively there could be an issue upstream, like running up to the pole or further out that would need escalation to maintenance first.
  • lilminxlilminx Posts: 25
    Jun 15, 2020
    dB levels on downstream range from 7.1-7.9, upstream 43.8-45.3.

    These levels have been checked by the Techs that have come out already but the disconnects are still occurring.
  • reds91185reds91185 Posts: 2,452
    Jun 15, 2020

    Can you post the full signal levels page?


  • lilminxlilminx Posts: 25
    Jun 15, 2020

    Sure, thank you!


    Downstream Bonded Channels
    ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectedUncorrectables
    1LockedQAM25629453000000 Hz7.4 dBmV41.3 dB00
    2LockedQAM25618381000000 Hz7.1 dBmV41.0 dB00
    3LockedQAM25619387000000 Hz7.0 dBmV40.8 dB00
    4LockedQAM25620393000000 Hz7.6 dBmV41.3 dB20
    5LockedQAM25621399000000 Hz7.8 dBmV41.3 dB00
    6LockedQAM25622405000000 Hz7.6 dBmV41.2 dB00
    7LockedQAM25623411000000 Hz7.6 dBmV41.2 dB00
    8LockedQAM25624417000000 Hz7.6 dBmV41.2 dB10
    9LockedQAM25625423000000 Hz7.6 dBmV41.2 dB00
    10LockedQAM25626429000000 Hz7.6 dBmV41.3 dB00
    11LockedQAM25627435000000 Hz7.5 dBmV41.2 dB00
    12LockedQAM25628447000000 Hz7.4 dBmV41.2 dB00
    13LockedQAM25617375000000 Hz7.1 dBmV41.1 dB10
    14LockedQAM25630459000000 Hz7.4 dBmV41.1 dB20
    15LockedQAM25631465000000 Hz7.7 dBmV41.3 dB10
    16LockedQAM25632471000000 Hz7.8 dBmV41.1 dB00


    Upstream Bonded Channels
    ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
    1LockedATDMA35120 Ksym/sec30600000 Hz43.8 dBmV
    2LockedATDMA25120 Ksym/sec24200000 Hz43.5 dBmV
    3LockedTDMA12560 Ksym/sec19400000 Hz43.8 dBmV
    4LockedATDMA45120 Ksym/sec37000000 Hz45.3 dBmV

  • reds91185reds91185 Posts: 2,452
    Jun 16, 2020

    I think there is a problem upstream somewhere that needs to be fixed that is beyond your house.  A family member had TWC/Spectrum for years and had constant disconnects that they just learned to live through.  Techs replaced everything multiple times with no change until one of them finally got the right maintenance crew engaged. 

  • lilminxlilminx Posts: 25
    Jun 16, 2020

    I believe they've already had a maintence crew person @reds91185  . At least that's what they told me and they also said the ticket was closed after that. But we're still experiencing disconnects. How do we go about getting the right person to investigate and fix their wiring problems outside our home? We're getting the run-around :/

  • Julia_RJulia_R Posts: 4,189 Lead Mod
    Jun 16, 2020


    During any of the tech visits did they replace the modem in use? 


    This would be a good step to take the current equipment out of the equasion.


    I would encourage trying one of the newer 3.1 modems. There is no charge for our equipment. It would certainly be worth a try. 


    If you still are having issues after the next visit please do contact us via our Social Media Customer Service team for assistance.


    Twitter: @Ask_Spectrum

    Facebook: https://www.facebook.com/Spectrum



  • lilminxlilminx Posts: 25
    Jun 16, 2020
    What 3.1 modem would you suggest @Julia_R ?
    We prefer combo modem/WiFi ideally SBG or Cisco. No Intel chipset.
    Advice? Thank you!
  • reds91185reds91185 Posts: 2,452
    Jun 16, 2020

    There's only one offered by Spectrum (although in three variants - the Ubee version definitely uses Broadcom) and are all stand alone modems. If you opt to buy your own 3.1 modem make sure it's on the approved list.


    Authorized Modems to Use on the Spectrum Network 


    The Arris SGB8300 is the only combo 3.1 listed for customer owned equipment but it uses the Intel chipset.

  • lilminxlilminx Posts: 25
    Jun 16, 2020

    Yes we're reviewing the approved list which looks like it was updated as of 5/27/2020. Our current modem that we bought is still an approved modem for the level of speed we currently pay for.

    We are hard-pressed to accept that it's the modem device itself as the disconnects happen between a specific window overnight. We would definitely accept it's a device issue if the disconnects are infrequent and would happen at unexpected times during the day as well, but it does not.

  • reds91185reds91185 Posts: 2,452
    Jun 16, 2020

    I would agree that the modem is not the likely culprit. It is almost always the first thing that gets blamed and/or changed out during the troubleshooting process. 


    If it were me, I would use one of their modems to use until the problem gets fixed. That way your customer-owned modem doesn't get scapegoated. 

  • lilminxlilminx Posts: 25
    Jun 16, 2020

    True. I know though that anything that's given to us is not as good as what we'd buy on our own. The most recent person we spoke to in Internet Technical Support was pushing the Hitron, but how do they not know that it's well documented about issues with some Intel chipsets. It's a piece of garbage and I was not happy that this was the modem that was suggested. That's why we've always done our research, cross-checked approved BYOM list and bought our own that could handle even higher U/D speed in case we decided to increase U/D in the future. Not impressed with Spec.

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