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Saturday, December 9th, 2023 5:59 PM

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Intermittent Internet Service with constant T3 Errors

I have a Motorola MB8600 modem and am getting frequent internet disconnections (varies between few times/day and once every two days)*, only able to be temporarily solved with restarting the modem.  Each restart also takes between 20-30 minutes, almost entirely establishing the upload connection.  Even when it's working, I only get 6.5 out of the 10 Mbit upload internet speed and get multiple T3 Errors every few minutes as well as only one bonded .  I still get the full 200 Mbit down.  I checked the coax cable as well and didn't see any breakage, though the Center Conductor on one side of the connector (facing modem) is bent about 5 degrees (I've read that shouldn't affect it much, but figured I mention it just in case).  I also have no splitters, it goes directly to my modem.

While I can get the channel info and event log while the internet is "working," I am unable to get it once it crashes the modem ends up freezing a minute or two later.*


* What I've noticed is that the internet consistently lasts longer if I clear the event log once in a while of its many, many, errors.

Downstream Bonded Channels

Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 17 489.0 5.1 39.9 135 0
   2 Locked QAM256 1 393.0 3.6 39.6 140 0
   3 Locked QAM256 2 399.0 3.6 39.6 126 0
   4 Locked QAM256 3 405.0 3.4 39.5 124 0
   5 Locked QAM256 4 411.0 3.7 39.6 113 0
   6 Locked QAM256 5 417.0 3.7 39.5 133 0
   7 Locked QAM256 6 423.0 3.6 39.4 152 0
   8 Locked QAM256 7 429.0 4.1 39.9 121 0
   9 Locked QAM256 8 435.0 4.1 39.7 152 0
   10 Locked QAM256 9 441.0 4.1 39.5 136 0
   11 Locked QAM256 10 447.0 4.5 39.9 149 0
   12 Locked QAM256 11 453.0 4.4 39.7 141 0
   13 Locked QAM256 12 459.0 4.5 39.7 139 0
   14 Locked QAM256 13 465.0 4.9 39.9 121 0
   15 Locked QAM256 14 471.0 4.9 39.7 136 0
   16 Locked QAM256 15 477.0 5.1 39.9 138 0
   17 Locked QAM256 16 483.0 5.2 40.1 113 0
   18 Locked QAM256 18 495.0 5.2 39.6 126 0
   19 Locked QAM256 19 507.0 5.0 39.9 142 0
   20 Locked QAM256 20 513.0 5.2 40.2 140 0
   21 Locked QAM256 21 519.0 5.0 40.0 154 0
   22 Locked QAM256 22 525.0 4.8 39.8 195 0
   23 Locked QAM256 23 531.0 4.9 39.9 145 0
   24 Locked QAM256 24 537.0 4.7 39.9 151 0
   25 Locked OFDM PLC 25 690.0 7.3 38.5 173957894 0
   26 Locked QAM256 26 543.0 4.8 40.0 190 0
   27 Locked QAM256 27 549.0 5.1 40.1 164 0
   28 Locked QAM256 28 555.0 5.1 39.9 193 0
   29 Locked QAM256 29 561.0 5.2 40.0 212 0
   30 Locked QAM256 30 567.0 5.4 40.1 202 0
   31 Locked QAM256 31 573.0 5.3 39.9 231 0
   32 Locked QAM256 32 579.0 5.4 39.8 239 0


Upstream Bonded Channels

 Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Not Locked SC-QAM 1 5120 16.3 39.0
   2 Not Locked SC-QAM 2 5120 22.8 28.5
   3 Not Locked SC-QAM 3 5120 29.2 39.0
   4 Locked SC-QAM 4 5120 35.6 39.0

Something to note:

The three unlocked channels seem to vary a fair bit, here's what it is just a few minutes later.

   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Not Locked SC-QAM 1 5120 16.3 33.8
   2 Not Locked SC-QAM 2 5120 22.8 30.8
   3 Not Locked SC-QAM 3 5120 29.2 34.5
   4 Locked SC-QAM 4 5120 35.6 39.0

And here's the connection while it struggles to get connected initially (not sure if it should just be higher since initialization might require it but figured more info is better than less)  Note: This upstream and downstream was not taken the same day as the rest of the data given, but the day before.

Downstream

Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
1 Locked QAM256 17 489.0 5.4 39.6 9 0

Upstream

Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
1 Not Locked SC-QAM 3 5120 29.2 64.0

* After connecting, the Pwr had dropped to around 40 dBmV

Small fraction of the Event Log (all the same type of errors):

Time Priority Description
12:14:52
Sat Dec 9 2023
Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:19:36
Sat Dec 9 2023
Critical (3) No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:19:36
Sat Dec 9 2023
Critical (3) Ranging Request Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:19:36
Sat Dec 9 2023
Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:20:00
Sat Dec 9 2023
Critical (3) No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:20:00
Sat Dec 9 2023
Critical (3) Ranging Request Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:20:00
Sat Dec 9 2023
Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:20:59
Sat Dec 9 2023
Critical (3) No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:20:59
Sat Dec 9 2023
Critical (3) Ranging Request Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:20:59
Sat Dec 9 2023
Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:24:40
Sat Dec 9 2023
Critical (3) No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:24:40
Sat Dec 9 2023
Critical (3) Ranging Request Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:24:40
Sat Dec 9 2023
Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:24:49
Sat Dec 9 2023
Critical (3) No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:24:49
Sat Dec 9 2023
Critical (3) Ranging Request Retries exhausted;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:24:49
Sat Dec 9 2023
Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:25:46
Sat Dec 9 2023
Critical (3) No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;

Update:

Changing out the cable made little to no difference in respect to the power levels of the channels.  However, when replacing the wire, I noticed that the grounding wire itself within the coax grounding block was severely corroded.  After scraping off corrosion and putting it back in, it seems to have solved one of my issues.  Instead of taking 20-30 minutes to get an initial connection when the modem is restarted, it only takes 2-4 minutes even with the old cord.

I am still having 3 unlocked channels and getting multiple T3 errors every few minutes though, so I'll have to reach out for someone to come by I guess.  For a couple minutes after initially reconnecting the ground I did manage to have the other channels locked and was getting twice the upload speed before it disconnected them again.

Accepted Solution

4 Messages

1 year ago

Final Update:

The tech just stopped by and fixed it.  So the original cord did cause the original issue as the flooring people ended up cutting the insulation where I couldn't see (years ago).  Apparently a while ago Xfinity put a filter on before our house because of the noisy signal.

The fix:

They ended up putting a new line in the house (instead of just bypassing the old one like I did) and removed the filter.  Everything's all good now.

Official Employee

 • 

1.5K Messages

This is excellent news [Edit: Personal Information]! Thanks for the details and the update! Glad to know everything is all good now. I would like to follow up with you on Friday to see how everything runs for you.

(edited)

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

Expert

 • 

110.2K Messages

1 year ago

There is something intermittent going on with the connectivity. Some stuff that you can try;

In an effort to try to obtain better connectivity, 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.

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it up to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.


Good luck !

Official Employee

 • 

1.2K Messages

1 year ago

Hello @kingknapp. There could be a couple of different issues that make you Internet speeds slow down. Wi-Fi is never guaranteed speeds. Also, old cable or damaged cable could be another issue. We can take a closer look for you and see what is going on. Please send us a direct message with your full name and full service address.

Expert

 • 

110.2K Messages

1 year ago

@kingknapp 

Did you get a chance to see if any of those tips apply ? Please update your topic right here on these public help forums.

4 Messages

1 year ago

Since I don't have any splitters, that's luckily not a problem I have to consider.  As for the wires, I checked all of it and didn't see any breaks, sharp turns, or corrosion on the wires/connectors.  Since a couple people stated it could be the wire though, I bought a RG 6 coax cable and I'll just replace the part that goes in the house and see if that fixes it.  The wire's 14+ years old so maybe it's broken down within the wire itself where I can't see it.  I'll post an update in a couple days after it arrives (shipping's been taking longer since holidays) and I've had the chance to do it.  If that doesn't fix it, I'll take William up on the offer and maybe try to get a tech out here if necessary. Thanks for the advice.

Official Employee

 • 

1.2K Messages

You are very welcome @kingknapp. We will be here if you need further assistance!

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
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

Expert

 • 

110.2K Messages

@kingknapp​ 

Thanks for the update ! So if it winds up that there is nothing more that can be done to improve the connection quality, then yes, you'll need a tech visit as stated. 


Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it up to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.


Good luck !

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

4 Messages

1 year ago

Update:

Changing out the cable made little to no difference in respect to the power levels of the channels.  However, when replacing the wire, I noticed that the grounding wire itself within the coax grounding block was severely corroded.  After scraping off corrosion and putting it back in, it seems to have solved one of my issues.  Instead of taking 20-30 minutes to get an initial connection when the modem is restarted, it only takes 2-4 minutes even with the old cord.

I am still having 3 unlocked channels and getting multiple T3 errors every few minutes though, so I'll have to reach out for someone to come by I guess.  For a couple minutes after initially reconnecting the ground I did manage to have the other channels locked and was getting twice the upload speed before it disconnected them again.

Official Employee

 • 

1.9K Messages

Hello kingknapp

We would love to help! Seems like there might be some ingress in the line. Coax is pretty temperamental if you are scraping at the conductor. If there are issues with the center conductor it will normally be swapped right away. That timing is way out the norm as far as loading and activation. 5 minutes would be within range of activation times but once activated coming back online should be quick. 

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

Expert

 • 

110.2K Messages

1 year ago

@kingknapp 

Tech time ! Good luck ! Please post back with how it goes.

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