U

Visitor

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2 Messages

Friday, January 28th, 2022 11:55 PM

Closed

Upper Downstream channels not locking

I have been having intermittent internet issues for about a year. Last year a tech was dispatched and after being in my home for 8 hours he left. I haven't had the time or patience to schedule another tech visit. The last month we were rebooting our XFi modem once or twice daily to keep the internet up. I finally went out and purchased a Netgear CM700 modem and TP-Link AX3000 router. Initial setup went smoothly, had an issue with the Downstream bonding light blinking. I spoke with Xfinity support and she advised me that the Downstream light flashing, meant that the modem was syncing with my Wi-Fi devices. After several minutes of explaining to her that a downstream light on a modem is in no way related to Wi-Fi scanning and that her response was absolutely absurd. She followed with an "If you say so". I then ended the chat and started looking for my own answers elsewhere. I also see a lot of UnCorrectables. Please see my signals pasted below:

<tabindex=-1>Startup Procedure</tabindex=-1>
Procedure Status Comment
Acquire Downstream Channel 393000000 Hz Locked
Connectivity State Ok Operational
Boot State Ok Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)

Downstream Bonded Channels (Partial Service)
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables UnCorrectables
1 Locked QAM 256 1 393000000 Hz -12.5 dBmV 33.8 dB 12602 3975
2 Locked QAM 256 2 399000000 Hz -10.5 dBmV 33.9 dB 1721175 30785
3 Locked QAM 256 3 405000000 Hz -9.7 dBmV 32.6 dB 15983807 19534463
4 Locked QAM 256 4 411000000 Hz -8.7 dBmV 35.7 dB 1597 1194
5 Locked QAM 256 5 417000000 Hz -8.0 dBmV 37.6 dB 1551 1098
6 Locked QAM 256 6 423000000 Hz -4.9 dBmV 38.9 dB 1167 1033
7 Locked QAM 256 7 429000000 Hz -7.9 dBmV 36.6 dB 24792 5434
8 Locked QAM 256 8 435000000 Hz -16.3 dBmV 31.6 dB 11260 4012
9 Locked QAM 256 9 441000000 Hz -10.7 dBmV 35.5 dB 6152 1047
10 Locked QAM 256 10 447000000 Hz -13.5 dBmV 33.8 dB 5269 2261
11 Locked QAM 256 11 453000000 Hz -18.4 dBmV 29.8 dB 5954364 28848
12 Locked QAM 256 12 459000000 Hz -11.5 dBmV 33.9 dB 470062 301851
13 Locked QAM 256 13 465000000 Hz -11.0 dBmV 35.0 dB 3376 1526
14 Locked QAM 256 14 471000000 Hz -15.0 dBmV 32.3 dB 15870 4857
15 Locked QAM 256 15 477000000 Hz -14.0 dBmV 33.8 dB 6906 2160
16 Locked QAM 256 16 483000000 Hz -12.9 dBmV 34.4 dB 771 1120
17 Locked QAM 256 17 489000000 Hz -15.3 dBmV 31.6 dB 4447 1168
18 Locked QAM 256 18 495000000 Hz -18.4 dBmV 29.4 dB 17366048 8893512
19 Locked QAM 256 19 507000000 Hz -14.2 dBmV 33.0 dB 1928 1466
20 Locked QAM 256 20 513000000 Hz -17.8 dBmV 30.1 dB 16516687 4076208
21 Locked QAM 256 21 519000000 Hz -15.0 dBmV 32.2 dB 17607050 4048315
22 Locked QAM 256 22 525000000 Hz -16.5 dBmV 30.3 dB 8434698 14389861
23 Locked QAM 256 23 531000000 Hz -21.0 dBmV 26.2 dB 504835407 284628475
24 Locked QAM 256 24 537000000 Hz -19.7 dBmV 28.0 dB 30956960 13569172
25 Locked QAM 256 25 543000000 Hz -22.0 dBmV 26.5 dB 547458879 84539494
26 Locked QAM 256 26 549000000 Hz -21.0 dBmV 27.5 dB 104990486 799098
27 Locked QAM 256 27 555000000 Hz -17.7 dBmV 29.6 dB 22529578 2294055
28 Locked QAM 256 32 585000000 Hz -20.3 dBmV 27.8 dB 66232812 592488
29 Not Locked N/A N/A 0 Hz 0.0 dBmV 0.0 dB 0 0
30 Not Locked N/A N/A 0 Hz 0.0 dBmV 0.0 dB 0 0
31 Not Locked N/A N/A 0 Hz 0.0 dBmV 0.0 dB 0 0
32 Not Locked N/A N/A 0 Hz 0.0 dBmV 0.0 dB 0 0

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 4 5120 Ksym/sec 17300000 Hz 40.8 dBmV
2 Locked ATDMA 3 5120 Ksym/sec 23700000 Hz 42.0 dBmV
3 Locked ATDMA 2 5120 Ksym/sec 30100000 Hz 42.0 dBmV
4 Locked ATDMA 1 5120 Ksym/sec 36500000 Hz 41.5 dBmV
5 Not Locked N/A Unknown 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked N/A Unknown 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked N/A Unknown 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked N/A Unknown 0 Ksym/sec 0 Hz 0.0 dBmV

Expert

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110.1K Messages

3 years ago

The downstream power levels and the downstream SNR's are out of spec (some are way out !). And there are large amounts of uncorrectable bit errors. 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 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, 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, 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 !

Official Employee

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695 Messages

3 years ago

Hello @user_24a512, did you still need a technician visit or is everything resolved?

Visitor

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2 Messages

@XfinityXavier​ I am trying to get a technician now. I have changed outlets within my house and still no change. I have noticed the issue is intermittent. One day its down in the morning, the next day at night. It's annoying. I am having a hard time communicating with the "help desk" people.

Official Employee

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1.7K Messages

@user_24a512, we can help schedule an appointment for you and you can also set one up if you follow troubleshooting steps from "My Account" after signing into https://comca.st/3ojIloV. If you use the Direct Message icon at the top of the page you can send your name and service address to "Xfinity Support." After locating your account, we can set up an appointment. 

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