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Motorola MB8611 with 1gig service frequently dropping connection and rebooting

OtherSarah5 Posts: 5 Spectator

Good morning.

Similar to another user experiencing problems with this exact model, our home internet has been experiencing seemingly random drops during the day. My partner and I work from home and have been disconnected from meetings several times.

We were experiencing connectivity drops with the Spectrum provided modem and with having a lower tier speed as well. Several remote troubleshooting rounds, with power cycling and checking cable connections, did not help and eventually a tech was sent out. The tech discovered that some of the outside connections had burn marks and a repair crew fixed those which provided us a few weeks of good connectivity.

Now we've had several series of drops within the last 2 days and can't seem to isolate the issue, including several drops while I typed this comment. I've attached a current report and the modem error logs with CM-MAC and CMTS-MAC blacked out.

Please let me know if I can provide any additional information to help troubleshoot this.

Seems likely a tech is needed to our address but would be happy to resolve remotely.

Thanks in advance.


  • James_M
    James_M Posts: 4,514 ✅ Verified Employee Moderator

    Hi & welcome!

    Sorry for any service issues. L:ooking at the screenshots provided, the screenshots were taken about 4 minutes after restarting the modem, so from a diagnostic POV, there is not much information to go on. I am seeing the brief interruptions that you are describing. We can try sending some refresh signals to the modem and see if that helps, otherwise it does look like you'll need another service call.

    Let us know if you wuld like us to send the refresh signals to the modem.


  • OtherSarah5
    OtherSarah5 Posts: 5 Spectator

    Hi there James, really appreciate the quick response.

    The timing for the restart makes sense, as while I was typing out my comment and pulling the most recent logs, we had an outage and the modem rebooted itself. This is pretty much what's happened I would say 75% of the times we have drops in connection.

    I should note that brief is a good description of the outage issue, as the modem does tend to restart (indicator lights all go off and then come back online) and restore both wired and wireless connection relatively quickly.

    Please let me know if I can monitor the modem for an amount of time and then provide additional screens. Modem has been online for about an hour now and the screens look largely the same including the event log as the ones I took and attached, though it sounds like that still might not be enough time to get a good picture.

    Otherwise, yes, refresh signals seem like they might be worth trying. Like I mentioned earlier, my partner and I both work from home so if there's any way to get some advanced warning right before we can expect a drop from the refresh we'd really appreciate it.

    Thanks for the help.

  • James_M
    James_M Posts: 4,514 ✅ Verified Employee Moderator

    Thanks. I sent the refresh signals. Let us know if there is an improvement or if the issue continues.

  • OtherSarah5
    OtherSarah5 Posts: 5 Spectator

    Hi again James. Thank you for sending the refresh signals out.

    Unfortunately, we only saw improvements until later in the evening, with the data connection drops starting again just before midnight. The issues are now happening this morning as well.

    Let me know if the modem's event log will be helpful and what other steps we can take.

    Thanks again.

  • James_M
    James_M Posts: 4,514 ✅ Verified Employee Moderator

    Thanks! Since the modem was recently reset, the reset clears the modem logs and there is currently no log information that stands out. There are still interruptions that can be seen in our diagnostic tool history. At this time, we would suggest scheduling another service call.

    Let us know how it goes and if we can assist further!

  • William_M
    William_M Posts: 964 ✅ Verified Employee Moderator
    edited February 2023

    Unfortunately there's only a limited amount of information to gather from looking at logs. If the lights change on the modem when you lose connection the problem must be with the modem or the signal coming to it.

    Since all the lights are turning off I'd recommend connecting it to a different power outlet to make sure it is not just an electrical issue. Try to move any other electronics away from the modem to minimize possible interference and make sure it is in a well ventilated area to rule out overheating.

    If the issue persists you will probably need to schedule another appointment with a technician. I understand you have had one but intermittent issues like this do sometimes take multiple, we can always fix the problem eventually with persistence and process of elimination!

  • OtherSarah5
    OtherSarah5 Posts: 5 Spectator
    edited February 2023

    Yes, the modem restarts itself almost every time the connection is lost.

    I'll reach out to the main support chat to schedule another technician to the home in that case.

    Edit: Thank you for also weighing in William, it's appreciated. I will try moving the modem and adjusting the power outlet when my partner and I are between meetings, as those are things we've not tried yet. The Spectrum main support chat is having trouble letting me schedule a tech visit for the moment but will also do that most likely to be sure we find what the issue may be. Thanks one more time to you and James for the help.

  • Hammerfest
    Hammerfest Posts: 2 Spectator


    Having a similar problem here.

    I saw someone else mention seeing the firmware get updated, then downgraded, etc etc, and I am seeing this as well.

    Did you perchance see what firmware version you where running on each restart? Or get the problem resolved.

  • XaviP
    XaviP Posts: 1 Newcomer
    edited February 2023


    Here is a thread from Xfinity about the same problem.

    Based on what's been figured out in there it's a firmware issue, where either the firmware from Motorola is incorrect or the way spectrum is receiving it so it can perform on their network is incorrect. Other users logs suggest it is the later.

    The suggestion is to wait for the cable company to acknowledge and then fix the problem or buy a new modem with the recommendation being the Arris 1G model, which sucks.

  • OtherSarah5
    OtherSarah5 Posts: 5 Spectator

    @XaviP @Hammerfest

    Sorry to hear about you having issues as well Hammer, can confirm it's one of the most infuriating things I've come across.

    Reading through that thread XaviP provided is really interesting. Current software version on ours is 8611-19.2.18, wouldn't be able to say when that was updated or what it was when problems started.

    As an update however, we managed to fix what we were running into for now. We had another Spectrum contractor tech come out to read the signal to the house and from several of the lines, during which no issues were found. As a last resort to match what both William here and the tech who visited suggested, I grabbed a CyberPower SL700U Standby UPS System (exact Amazon phrasing for anyone who wants to try exactly what we did) and hooked that into a different power outlet from before. Since plugging into the battery backup ports on that UPS, we've had no drops at all and the modem, instead of restarting over and over, has been up and running for the last nearly 6 days. It's bizarre but that seems to have done the trick for ours for now.

    Possible the firmware for the modem currently is sensitive to power delivery but I couldn't say for sure. Hope this might help anyone else that might be running into this.

  • Hammerfest
    Hammerfest Posts: 2 Spectator
    edited February 2023

    Interesting, I always run a UPS for my core networking equipment, did also try direct wall plug just-in-case.

    8611-19.2.20 and 8611-21.3.7 are the two mine are bouncing between, mine is newer so doesnt have .18 which is probably the fallback

    Ya, I talked to Motorola and they blame Spectrum since they provide it to Spectrum soooo ya, not expecting a resolution, might look at the Arris S33 which runs HOT but at least has the 2.5Gbit port I desire

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