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Saturday, September 7th, 2024 1:22 AM

Intermittent internet outages.

I get several outings per week.  Most last just a few minutes.  Recently there have been some longer outings.  Every time I check the outage map it says everything is fine.

A couple weeks ago I bought a new router and modem.  Set them up, and still couldn't connect even though the outage map sad there were no problems.

I tried the old modem and I was able to connect.  As far as I could tell the new modem didn't do any better than the old one.  I returned the new modem, I'm currently using a Netgear CM500.

During the time of the trouble sometimes i could get to the internet with the old modem when connected to a hardwire even when the downstream light was red.  it seemed like the old modem would go in and out, but the new modem was always out.  It made me wonder if the new modem used tighter tolerances or something... like maybe the old modem was like, meh, good enough.

 

For about a week I was fine.  Then today, I couldn't connect for several hours.

I tried a hard wire directly from modem to a computer, didn't work.  All of the lights on the modem were good (on, green)

***:  This one seemed really weird - while connected hardwire I couldn't even get 192.168.100.1 to come up.  Am i correct in thinking that even if I don't have internet connectivity this should be available to me?

When the internet is working correctly i can get to 192.168.100.1 and it appears everything is in spec.  downstream power channels are all within -2 to -3.  upstream are all 54.  snr (i assume this is signal to noise ratio) is 42 something for all 16 locked channels.

During the time I couldn't connect, I went to xfinity support and ran the test to see if they can connect to my modem, it passed the test, said it could connect.

Are there other tests I could run?  

Thanks for any ideas!

[Edited:PII]

Official Employee

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1.6K Messages

2 months ago

 

GrandRapidsMI Thank you so much for making a post for help with your connection issues. We are always happy to help make sure you have the connection you need. The CM500 is not currently supported we do support the CM500-100NAS I would start by confirming your model number. You can use our Device information page to see all of our currently supported devices. If you are using the CM500-100NAS it is rated to support up to 372 Mbps so if you are using a speed tier higher than that you would encounter connection issues.  You can also check out this page our Experts have helped us compile for more troubleshooting options.  

 

Expert

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107.1K Messages

2 months ago

@GrandRapidsMI wrote: "upstream are all 54."

If that's not a typo, the upstream power is too high /  out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are 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 from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, etc.

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.


Good luck with it !

1 Message

Soon after we got service in 2022 several houses were built across the street and my service has had these same brief disconnects as are discussed above. Comcast tech support is useless as they just go through the same motions wasting my time. I had one good tech that came out but he was as disgusted with Comcast as I am since he truly wanted to get the problem fixed but they would not let him. Comcast replaced the router 3 times, repulsed all wire from the pole to the router and all the tests work perfectly but if you are doing VoIP or zoom the service cannot drop even for a few seconds. 

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