urdypooh's profile

Frequent Visitor

 • 

18 Messages

Thu, Sep 23, 2021 3:16 AM

SB6183 and just 1 channel up

Today my modem rebooted and afterwards I had all 16 channels bonded for download but just 1 channel for upload. New reboots didn't resolve the issue.

I contacted support (got dropped when they asked me to run a speedtest) and they said that everything is okay after changing the profile (?) without rebooting the modem afterwards. I get 450 Mbps on download and 12 Mbps upload with this 16x1 setup which is basically what I pay for.

I have seen quite a few uncorectable errors lately but I don't know if that is connected to this upload channel problem. 

My fear is that

a) Comcast is no longer supporting DOCSIS 3.0 modems

b) during busy times I will not get my upload speed anymore as there is just one channel available. 

How do I get my modem back to 16x4?

Thank you

EG

Expert

 • 

89.9K Messages

1 m ago

What do the modem's signal stats look like ? Try getting them here; http://192.168.100.1 or here http://10.0.0.1 


Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.

(edited)

urdypooh

Frequent Visitor

 • 

18 Messages

1 m ago

I rebooted this morning on the off chance that something might have changed and it did: I have all 4 upstream levels back.

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked QAM256 4 507000000 Hz -16.8 dBmV 33.2 dB 0 0
2 Locked QAM256 5 513000000 Hz -16.5 dBmV 34.9 dB 0 0
3 Locked QAM256 6 519000000 Hz -16.9 dBmV 34.6 dB 0 0
4 Locked QAM256 7 525000000 Hz -16.8 dBmV 34.6 dB 0 0
5 Locked QAM256 8 531000000 Hz -17.0 dBmV 34.5 dB 0 0
6 Locked QAM256 9 537000000 Hz -17.4 dBmV 34.1 dB 0 0
7 Locked QAM256 10 543000000 Hz -17.2 dBmV 34.3 dB 0 0
8 Locked QAM256 11 549000000 Hz -17.5 dBmV 34.0 dB 0 0
9 Locked QAM256 12 555000000 Hz -17.1 dBmV 34.1 dB 0 0
10 Locked QAM256 13 561000000 Hz -17.5 dBmV 34.0 dB 0 0
11 Locked QAM256 14 567000000 Hz -17.5 dBmV 34.0 dB 0 0
12 Locked QAM256 15 573000000 Hz -17.6 dBmV 33.9 dB 1 0
13 Locked QAM256 16 579000000 Hz -17.9 dBmV 33.6 dB 0 0
14 Locked QAM256 17 585000000 Hz -17.5 dBmV 33.9 dB 0 0
15 Locked QAM256 18 591000000 Hz -17.8 dBmV 33.6 dB 0 0
16 Locked QAM256 19 597000000 Hz -17.3 dBmV 34.1 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 35600000 Hz 54.0 dBmV
2 Locked ATDMA 1 5120 Ksym/sec 16400000 Hz 54.0 dBmV
3 Locked ATDMA 2 5120 Ksym/sec 22800000 Hz 54.0 dBmV
4 Locked ATDMA 3 5120 Ksym/sec 29200000 Hz 54.0 dBmV

Official Employee

 • 

439 Messages

@urdypooh, have you tried troubleshooting and following EG’s recommendations? With poor signal quality making sure all your connections are tight, secure, and in good connection can make a huge difference. Bypassing and replacing splitters is always something to consider. If you have done all you can send us a DM with your name and service address. Use the Direct Message icon on the top of the page to send your message to “Xfinity Support.” I have seen channel issues resolved after a technician has made repairs to improve signal quality. This may be what we need!

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
EG

Expert

 • 

89.9K Messages

1 m ago

Everything is WAY 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 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 !

New to the Community?

Start Here