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Slow Gigabit service // Missing D3.1 OFDM channel *PLEASE HELP*.

Frequent Visitor

Slow Gigabit service // Missing D3.1 OFDM channel *PLEASE HELP*.

Hello,

I recently upgraded to Gigabit service roughly 3 months ago.  Over the past 2 months everything has been working flawlessly and speeds have been consistently 945mbps / 43mbps when doing speed test.  The past maybe 3 weeks, my speeds are now as low as 350mbps with an average of 650mbps.  Upon looking at my modem status page, I see my modem is no longer bonding to the D3.1 OFDM channel and only bonding to 24 d3.0 channels.  Nothing has changed, and i've had two tech out already and both determined nothing is wrong locally.

 

I have my own purchased Netgear CM1000 purchased from Amazon, but now exchanged for a Netgear CM1000 purchased at my local BestBuy.

 

After all my troubleshooting & multiple tech visit i'm starting to believe this may be a firmware bug (I was running firmware 3.01.04, but now have firmware 3.01.06) or maybe a CMTS issue, but unable to gather any further information on that.  I'm hoping someone may have some experience in troubleshooting this issue or maybe a Comcast agent can help track down this issue as at this point, i'm completely lost.

 

ANY useful help would be appreciated.  I've included screenshots of my signal levels, event logs & firmware page.  Please let me know if any more information is needed.

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Expert

Re: Slow Gigabit service // Missing D3.1 OFDM channel *PLEASE HELP*.

Has the modem first been powercycled / re-started  ? Still no joy ? Has it been hard reset to factory defaults by pressing and holding in the recessed reset button on the rear for 30 seconds. 



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Frequent Visitor

Re: Slow Gigabit service // Missing D3.1 OFDM channel *PLEASE HELP*.

Hello,
Yes the modem has been factory reset multiple times by the admin page and by the reset button on the modem. I've also swapped out coax lines between the modem and wall plate.
Expert

Re: Slow Gigabit service // Missing D3.1 OFDM channel *PLEASE HELP*.

Hi @s3v3n

Thank you for visiting the forums! Sorry to hear about your issues. 

 

I've asked a Comcast employee to check your modem and node health. You should expect a reply in this thread. 




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Frequent Visitor

Re: Slow Gigabit service // Missing D3.1 OFDM channel *PLEASE HELP*.

Thank you.  Hopefully they can tell me more information than the phone reps, chat reps or the technicians i've had out so far in trying to resolve this issue.

Official Employee

Re: Gigabit service for at least 3 months, now missing OFDM channel.

Hi there, s3v3n. Welcome to our Community and thank you for posting. With a purchased device, we're very limited with what we can do and what we can check on it. We can make sure that the signal strength getting up to the modem is up to par (one of the things that is definitely in our control) but we're not able to log into the device to check settings and specifics like we'd be able to do if it were a leased device. It sounds like signal strength at your premise has been checked twice, which can help us narrow a few things down as far as that goes. As far as firmware goes - it's extremely unlikely for it to be an issue/bug within that aspect, but it's not impossible. Really with purchased equipment concerns of this nature, we often have to refer you to the manufacturer of the device for them to log into it and work with you to determine why these things are happening with it. That is especially the case if your hardwired speed is coming through as it should be for your speed tier. Either way, please go ahead and send me a private message with your name so I can take a look at some information on my end and we can go from there.

 

To send a private message, please click my name "ComcastMorgan" then select "Send a Message" on the right side.

 

Thank you!


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Frequent Visitor

Re: Gigabit service for at least 3 months, now missing OFDM channel.

I'm not trying to be ignorant with my following comment; However if your just going to check my signal levels and tell me to reboot my modem, I'd rather not waste your time or mine. At this point it is either a firmware or a CMTS issue. I have purchased a new modem (same model) with the exact same issue.
Frequent Visitor

Re: Gigabit service for at least 3 months, now missing OFDM channel.

Issue Resolved, Unknown fix as problem corrected itself.  

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Silver Problem Solver

Re: Gigabit service for at least 3 months, now missing OFDM channel.

Can you mark this thread as resolved?

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Official Employee

Re: Gigabit service for at least 3 months, now missing OFDM channel.

 

Hi, s3v3n. I'm glad to hear the issue has been resolved. Thanks for reaching out and take care. 


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