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Forum Discussion
CM1150V modem frequent and long reconnects more recently - upstream channel issue.
Hi, I found this forum somewhat helpful and and going to post my experience troubleshooting a problem with the CM1150V. I have not found root cause, but seem to have resolved it for now swapping ou...
My problem was 100% an issue further up the line from my interface at my home.
Two techs had been out and said 'everything was good'
I asked the second tech NOT to close the ticket and to escalate to line/network. He also gave me local Supervisors card.
I contacted the local supervisor (it was awkward timing over the Christmas/New Year period) but we connected by phone ultimately. He committed to have line/network investigate.
What I did for my own part in the interim was eliminate the TV Splitter to improve the signal levels to my modem.
Next morning my internet went out and I thought 'here we go again' - then my wife mentioned she could see TWO trucks down at the main road (one actually at a subterranean box on the sidewalk out on main road and another at the intersection of that street and the one that intesects with mine). I went across the road and spoke to the technician - he said there was certainly higher levels on my line, although not what they would say 'out of spec' - however he swapped the circuit anyway (I do not know whether he swapped my line to another circuit, or whether he replaced some interface board in the box)
Afterwards I could immediately see improved signal levels at my modem.
That is now 3 full months since they did that correction out on the main road and it has been absolutely flawless since.
Your symptoms were exactly similar to mine - at 48db upstream, it was troublesome - removing the splitter dropped the level down a bit (but in my case it was over 59 with the splitter in place). Replacing the modem with a brand new Netgear replacement made no difference - well let me clarify that - I had a temporary XB7 modem and did not have the problem; thinking 'it must be the modem' I eventually got Netgear to authorize a replacement. That actually worked fine for about 2 weeks before the exact same issues manifested themselves.
With all the issues which were ultimately resolved by line/network I insisted on credits from Xfinity for both the temporary XB7 rental charge and loss of service use. I was satsified with the level of service given to this resolution.
Ultimately I also decided to eliminate Xfinity TV and switch to YouTubeTV - that got rid of the splitter permanently and also the TVBoxes Equipment and DVR charges - I retained the same service level of Internet service. I'm saving about $60/month with Xfinity Internet +YouTubeTV - also REALLY happy with YouTubeTV relative to Xfinity TV - it exceeded my expectations.
Hope all that helps - you need to try to move it further up the chain than the FIrst Response Tech who does your home service check. I was polite but firm in not accepting there was nothing wrong. Even if 'supposedly' within their 'acceptable' specs it is clear the Netgear is less tolerant at those higher upstream power levels - but it IS a recommended device from Xfinity so they need to do what is necessary to make it work.
p.s. I just did a quick check of my Upstream Power Levels - 2 channels at 46 and two at 45.5 (should note that I have no splitter installed and that would raise those levels by about 3 db - I cannot comment on whether or not the old problem would be present with the splitter installed.)
But these levels are lower than I had at any time before. I had 47 when I first installed the replacement Netgear modem (it worked when first installed) and I am quite sure that number was with the splitter removed.
have this exact same issue. Either no connection or slowed to a crawl for 30+ mins. Comcast saw no issues on their end. All my wiring checked out. T3 timeouts and higher upstream levels as well. Skipped the hoobaloo with comcasts techs. Replaced with a Arris 6183 which is working fine now. 2 year old 1150V modem which im keeping for another house. Worked fine till a week ago when it started timing out.
So my problem re-appeared
It had been working perfectly for 4 months since they interceded over at the main box on the street.
Then I started having internmittent problems about 3 weeks ago - saw a tech truck over on the main road; he said they had just replaced an amplifier board and had been working on 'other line issues on that whole section
Well my Upstream Power levels were back at 48 again and error log full of the T3 timeouts and other errors
Got an XB7 from Comcast and its perfect again.
I am now convinced that the problem is indeed line-based HOWEVER the CM1150V is MUCH more sensitive to this than the XB7 (or per Talisman12 the Arris)
So - is this really a CM1150V design issue?
Or a Line issue where it just happens to be exposed on the Netgear ........
I don't know how accurate the reported power levels are in the modem GUI but it's interesting to note that my levels in the Netgear were 48 dBmV vs 41 on the XB7.
After so many outages and time wasted with Comcast, they sent me an XB7 which I'm reluctantly renting and using while we work from home. Even when the upstream signal was above 48 dBmV, the XB7 doesn't require a hard reboot to get it back online.
When the tech came out he said signal at the point of entry were fine, but inside the cable on my home's point of entry, he ended up replacing the splitter, some connectors and a ground. Now my upstream signal is stable at an average of 42 dBmV on the XB7.
From having researched this problem for so many months, I do think the 1150v is much more sensitive to high upstream signals than the XB7 and likely any other non-Netgear modem. When work settles down, I'll try to reactivate the 1150v and hope that the upstream signal never reaches 48 dBmV again, tanking my network.