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My Comcast connection is crippled. Loss of Sync AND T3 time-out errors ALL DAY LONG.

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My Comcast connection is crippled. Loss of Sync AND T3 time-out errors ALL DAY LONG.

I have been using a (purchased) SurfBoard SB6141 for years with little to no issues. Recently I have been having a terrible time with my Comcast connection. If I unplug the modem it usually gets better for a little bit. Otherwise the connection constantly drops and cripples all my devices. My August Home lock tells me its been disconnected all the time. My Nest Camera drops all day long. Sometimes I am unable to stream anything and/or have major buffering issues while streaming. I unplug the modem and router and it temporarily helps. I also work from home so its slowly driving me crazy.

 

Yesterday I called Comcast (when I was getting consistently terrible speeds) and they sent a reset command which temporarily made it better. At the same time I scheduled a technician to come out and diagnose the problem (tomorrow morning). I also ordered a new SB6183 just in case its a modem problem. I have tried a new co-axial cable from the wall (only outlet being used) to the modem but am getting the same behavior. The more I read the more I am thinking it's a problem with the Comcast wiring outside the house.

 

Just wondering if anyone can look at the Signal and Logs (below) and give me feedback as to whether its a modem or connection problem? If it's a connection problem I will probably return the SB6183. If its a modem problem I very well might cancel the Comcast appointment (so I do not get charged for it being a modem problem). This is the deepest I have dove into the inter-workings of a modem so thanks for any and all enlightenment!

 

Logs from this morning (same as below)

Time Priority Code Message

May 26 2019 8:52:41 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 8:03:04 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 8:00:58 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 7:58:51 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 7:58:50 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 7:21:38 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 7:19:59 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 7:17:29 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 7:17:26 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 6:16:15 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 6:16:10 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 6:14:45 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 6:14:43 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 6:05:58 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 6:05:58 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 5:55:20 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 5:54:18 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 5:52:35 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 5:52:23 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

May 26 2019 5:50:20 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=78:96:84:fa:4e:15;CMTS-MAC=00:01:5c:64:3e:53;CM-QOS=1.1;CM-VER=3.0;

Logs: https://imgur.com/a/tlZzatv

Signal: https://imgur.com/a/EspAtrx

Expert

Re: My Comcast connection is crippled. Loss of Sync AND T3 time-out errors ALL DAY LONG.

The upstream power is on the high side and it may be intermittently fluctuating even higher to out of spec levels. 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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