312customer's profile

New Poster


4 Messages

Tue, Jun 30, 2020 7:00 AM

(Internet Issue) Seeking Guidance From Other Customers

So long story short, Comcast will not help me. They will only provide basic troubleshooting, restart modem, change cables, don't use your router, etc. But my problem is more complex than that. Comcast says they will send a technician out, but it's been 4 months and they just won't accomidate in our current pandemic economy. So I'm turning to the community forums for assistance. TIA to anyone with the time to read and provide suggestions.


So what's my problem? Well, the end-user experience is high-latency spikes, packet-loss, etc.


When I inspect my cable modem logs, I see very high counts of errors/corrections (see images). When I try and communicate this to Comcast support, they have no idea what I'm talking about and go back to the, unplug/replug/try-again troubleshooting steps.


So here's my question, do you think this is a sigal strength issue? Or potentially a cabling issue from Comcast to my house?


The environment is a single family home with only 1 splitter in the chain to TV/modem. The cabling install and splitter was provided by Comcast 5 years ago when I 1st moved in. I had great service up until 1.5 years ago. Conviently, I'm in a 2 year contract and I think Comcast is not inclined to help a customer who's locked in.


1st image is the modem after being on for a long time (weeks). Note the high error counts.


The 2nd image is right after reboot (minutes). Note the channel with an enormous amount of errors.




Regular Contributor


179 Messages

1 y ago

5 years is 10x enough time for cable connectors to get loose due to temperature swings...   We trust you but you haven't necessarily proven the idea that any modem error counter are relating to issues but please consider to eliminate the TV/splitter for a test, get modem attached directly to demarc coax, no splitter, only gold-plated connector inbetween tightened properly.  


I saw similar failures at my place and attributed the cause to 2.4Ghz radio being selected by the devices showing problems, and the 2.4Ghz radio failing in the non-xfinity router/wifi/hub that I have used for years.     The root of the problem appears to be this non-xfinity router/wifi/hub and I will swap it for some vendor's wifi 6E router/wifi/hub/gateway when available.    Hmm, does xFi have 6E?!   Locally fwiw, relocating wifi/router/hub to mancave/telecommute room has solved the throughput problems seen by me & family so far, as more devices can select 5Ghz wifi radio now. 

New Poster


4 Messages

1 y ago

Great suggestion about tempurature swings! I'm in Chicago and the handoff between Comcast/my cables are in the garage.


My todo list:

  • Check the connections. Retighten.
  • Going to spray some electrical contact cleaner as well.
  • Remove the splitter and go direct to modem.

Additional Info:

  • I am using my own cable modem (ARRIS SURFboard SB8200)
  • My latency/loss issues are entirely over wired connections (CAT6A) My switches are managed and I don't see any error counters on the ports involved. But I'm going to go recheck incase I'm making a bad assumption.



87.2K Messages

1 y ago

Looks like you have some extraneous noise ingressing into the lines somewhere. Try what you mentioned but it may be best to have a tech out to investigate. They have the proper equipment to track down where the noise is leaking in rather than guessing. Good luck with it !

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