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Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

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Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

Hello,

 

A couple of days ago I received my new DPC3941T gateway in the mail to replace my Technicolor I've had since about 2014. My TC was in Bridge Mode since about day 1 of my install and I've never really had any problems with the service. I currently have the new DPC in bridge mode to the same router as well, which is a Netgear Nighthawk R7000. I used the new coaxial cable provided with the new gateway and hooked it up to the same wall connector as before. 

 

I have the Blast 150 (200 now?) and with my new gateway I'm hitting some incredible speeds, which I am of course happy about. However, ever since getting and installing the new DPC, I've lost connection around the tail end of 9PM EST while watching Netflix. The whole network goes down and my router loses connectivity as well. Without rebooting or troubleshooting at all, the connection just comes right back up a minute or so later. My DPC's event logs indicate only that "erouter0 got new IP x.x.x.x" but the IP address is always the same. In looking at the logs, it appears that while I am work the same thing is happening.

 

Capture.PNG

 

However, these are the expiry settings that the DPC arrived with:

expiry.PNG

 

I generally see people posting the downstream/upstream statistics and did compare them to the troubleshooting page that is usually provided. It appears my Upstream power level is a tad high, but I couldn't tell you what my old gateway's levels ran at.

dsusstats.PNG

 

 

Sorry for the walltext and whatnot, just wanted to be thorough. Before swapping out any cables or changing this and that, based on the information I've provided, what should be the first thing I do to troubleshoot my issue? In about 3 hours (if tonight is like the past couple of nights) I'm due to lose connection, so I can capture anything needed then.

 

FWIW I can also run Wireshark across my whole network to catch anything specific if needed.

 

Thanks,

Michelle

Expert

Re: Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

The upstream power is too high / out of spec and it may be intermittently fluctuating even higher out of spec. That can cause 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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Frequent Visitor

Re: Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

Hi EG,

 

I do not have any splitters or things like that, as I only sub to the internet services, so that shortens things. I do have another coaxial entry on the opposite wall I can try to hook up to.  Additionally, I still have the original coaxial cable that the technician installed me with which is still in great condition. The tech crimped it fresh infront of me, connectors labeled RPC EX6 14, cable labeled Perfect Flex 6 Series/Rated AWG 18. New cable also rated the same and also a Perfect Flex 6 but with those fancy push connectors.

 

Should I perhaps try swapping the coaxial cable first ? I won't try that unless it is deemed OK to do. The new coaxial cable I received is about 1/2 the length of the old one I had and I wonder if that is maybe why I didn't have this problem before.

 

Until then, I'll check the wall entry for corrosion/oxidation, since the new coax from Comcast is sparkling and then move on to the other wall entry. Nail-biting that I have to wait until the next day to find out what works!

 

Thanks!

Official Employee

Re: Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

 

Potato117, sorry for the other thread I opened for you not knowing this was here! 

 

Shoot me a private message when you're ready. 

 

KenF


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Frequent Visitor

Re: Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

Quick update:

 

Last night I reseated the coaxial ends and powercycled the gateway. I did not experience the disconnect (occuring at tail end of 8PM EST not 9PM, my mistake), but according to my logs it appears sometime overnight or during the day (logs in UTC?) there were a couple of failed ranging attempts. My service is currently up and running. I've PM'd @ComcastKenF at their request with my info, so I'll keep the thread updated throughout.

 

 

Expert

Re: Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

Post what the signal stats look like now.



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Re: Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

Upon checking here and there during the weekend, the signal stats were still hovering in 53~54 area. I've had no issues since the reseat of the cable and my devices have been holding steady in the upper 200Mbps area.

Expert

Re: Intermittent Connectivity - Upgraded to DPC3941T from TC8305C

It's still too high. It's a problem just waiting to come back.



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