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SB8200 no longer showing Docsis 3.1 mode

Regular Visitor

SB8200 no longer showing Docsis 3.1 mode

In the last week or so I've noticed that my SB8200 downstream and upstream LEDs are both green, indicating Docsis 3.0 mode, but they used to show blue. It doesn't look like there's a problem (haven't seen any connection drops, or slower speeds), but it seems odd. Should I be concerned about the mode change? Signal levels and SNR levels look okay, except for upstream power looks a bit high: about 54dBmV.

Expert

Re: SB8200 no longer showing Docsis 3.1 mode

The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. That can cause the un-bonding of channels, random disconnects, spontaneous re-booting of the modem, and speed and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.



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Official Employee

Re: SB8200 no longer showing Docsis 3.1 mode

That's phenomenal advice EG!

 

Hi emenard. We appreciate you visiting and posting on our Forums. If none of that advice didn't work, I can further troubleshoot your modem's Internet connectivity issues. In order to have a better insight, I will have to poll the CMTS for real-time and historical RF signal reports from your modem, and check your local Node/Plant for signal degradation / errors. To get started, please send me a private message and include your full name so I can access your account. 


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Regular Visitor

Re: SB8200 no longer showing Docsis 3.1 mode

Thanks very much ComcastJoeTru!

A technician came out and it looks like there's some external equipment that has a problem. A repair order was issued and I was told it should be fixed in a day or two.

Thanks so much for you help!

Expert

Re: SB8200 no longer showing Docsis 3.1 mode

YW.........



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I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
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Official Employee

Re: SB8200 no longer showing Docsis 3.1 mode

Hi emenard, glad we were able to reach a resolution for you. Thank you for creating the post, and thank you for using the Forums! This post has now been locked. Please don't hesitate to send a private message if you need any further help, or create a new post if you need assistance with anything else.


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Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!