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user_rzs99n
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4 Messages

Wednesday, November 26th, 2025 10:00 PM

Upstream Channels not locking

Hi, I need help with a clear upstream signal issue on my XB8. My modem cannot lock the required upstream channels. Upstream channels 1, 2, and 3 all show “Not Locked,” and my DOCSIS 3.1 OFDMA upstream channel (41) is locked but has a symbol rate of 0, which indicates the CMTS has disabled it due to noise. My upstream transmit power stays around 29–31 dBmV, confirming a return-path RF impairment. Downstream channels are normal. This is causing constant packet loss, lag spikes, Discord voice dropouts, and general upload instability. This is not a WiFi or equipment problem. It is a return-path issue at the tap, drop line, or node, and requires a line technician or maintenance tech. Please escalate.

This problem has been persisting the past week and has made the internet pretty unusable at times which is critical for me since I work from home and shouldn't have to deal with this. Sometimes there are no upstream channels at all.

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4 hours ago

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XfinityAlyssaA

Official Employee

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2.3K Messages

21 days ago

Good afternoon @user_rzs99n and thank you for reaching out on our Forums regarding your upstream channel issues and for providing that screenshot, we appreciate it. We are happy to help schedule a tech visit to investigate your concerns further. To get started, can you please send us a Direct Message with your first and last name along with the service address on the account?

To send a "Direct Message" ("Private") message:

Click "Sign In" if necessary

  • Click the "Direct Message chat" icon
  • Click the "New message" (pencil and paper) icon
  • Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
  • Type your message in the text area near the bottom of the window
  • Press Enter to send it

We look forward to working with you further! 

 

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user_hib0pa

Visitor

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1 Message

2 days ago

Hello - Was this ever resolved? I'm experiencing similar issues.

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XfinityAmira

Official Employee

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4.6K Messages

HI user_hib0pa! Thanks for reaching out on our Xfinity Forum, letting us know you're experiencing similar upstream signal issues on your end. My team is here to help and would be more than happy to further troubleshoot with you.

 

I see you have already sent us a Direct Message. Please note that sending unsolicited direct messages is a violation of our forum guidelines. You must first create a Public post requesting assistance, and once a Comcast-verified employee responds and asks for a direct message to be sent, you can then proceed with doing so. This is just a heads-up for future reference, but I look forward to further assisting you via that direct message. 

 

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