Constant connection drops and "SYNC Timing Synchronization failure"/"No Ranging Response received - T3 time-out" errors

Greetings, @user_c26111! I hope your week has been treating you well. Thanks so much for taking a moment out of your busy day to leave a post on our community forum. I'm sorry to hear you're having issues with your service, but you have definitely come to the right place for assistance.

 

If you were having the exact same issue across multiple modems, then it stands to reason the issue is happening at some point before the signal reaches your modem. It seems like the connection points that were replaced by the technician made a difference at first, but if the issues returned after a period of time, then there may be more points of degradation along the line path that need to be checked out.

 

If you could send our team a private message with your full name, the name listed on the account (if different), and the service address associated with your account, I'd be more than happy to look into this for you.

 

To send a Private Message, please click on the chat icon in the top-right corner of the screen, next to the bell icon, and then type or select "Xfinity Support" to initiate a live session.

Just wanted to update the post with the most recent information.

A technician was sent out on Tuesday and, just like the previous visits, the technician replaced a couple of cable fittings and reset the modem which has not resolved the issue.

I wrote a custom script that grabs the modem logs every couple of minutes while my laptop is running and while the occurrences have gone down in frequency, they are still occurring daily.

Most recent logs

Time Not Established  Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established  Critical (3) No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Time Not Established  Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established  Critical (3) No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Time Not Established  Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established  Critical (3) No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
18:55:16 Thu Aug 25 2022 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
10:05:36 Fri Aug 26 2022 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
10:05:36 Fri Aug 26 2022 Critical (3) Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
10:05:36 Fri Aug 26 2022 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Time Not Established  Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established  Critical (3) No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
Time Not Established  Notice (6) Honoring MDD; IP provisioning mode = IPv6
10:23:34 Fri Aug 26 2022 Notice (6) DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;
10:23:49 Fri Aug 26 2022 Notice (6) CM-STATUS message sent. Event Type Code: 24; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0.;CM-MAC=xx:xx:xx:xx:xx:xx;CMTS-MAC=xx:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;%

Still communicating over DM with Comcast and will keep this post updated with any developments.

Popping in to update again.

Have now had 3 techs come out who all poked at the 25' cable running from outside the house directly into the modem and the issues have persisted continuously (if not gotten worse).

Was told there was a work order to have some kind of upstream work done that was supposed to happen weeks ago but I have seen no evidence that any work has been done ( my neighborhood is all buried cable from the entrance of the subdivision and I have personally walked the neighborhood numerous times and have not seen any signs of any digging having been done).

Waiting to hear back from Comcast in our DM's for next steps.

Another tech, another nothing burger being done.

Decided to walk by the terminal nodes leading up to my house today and was not surprised to find the ones leading up to my house have all sorts of major glaring issues that could easily be responsible for the upstream signal issues. I have now documented these with photos and have provided all this information to support via DM's but I'm being told that the actual techs are the only ones capable of getting the people responsible for these upstream nodes to come out.

I'm no expert but the state of these terminals is just not acceptable. The one in the worst shape had it's door just wide open to the elements, an unburied cable coming out of it, and has broken connectors(may have been termination ends for unused ports at one point but thats not what they are anymore!) on 2 of the terminal ports.

After nearly 3 months, 6 tech visits, and countless hours of time spent dealing with this issue, it's finally (mostly) resolved.

Since the 2nd tech visit it's been clear that the issue was outside of my home and somewhere upstream. During each visit I gave the new tech a full run down of what had already been done and was actually able to quite quickly convince the last two techs that the issues were upstream.

Unfortunately, the contractors that Xfinity sends out for these calls appear to be only focused on getting in and out as quickly as possible and getting you to take their "Feedback survey" as soon as they leave the house. Both of the last 2 techs that came out gave almost identical experiences.

1. They came out and hooked up their test device to the outside line for 10 minutes
2. Came back in and said they didn't see any issues
3. I would go through the process of pulling up the modem logs and connection details showing uncorrected errors galore sometime within the last 12 hours
4. They would then agree the problem was upstream and tell me they were going to open a work order to have someone come out and check the upstream stuff.
5. They would give me their personal cell phone number and emphasize that I should only reach out to them directly going forward for any updates
6. I would get the speech about how I would be receiving a feedback survey after they leave and to please give them a 10 ( which I have not and will not be doing )
7. I would follow up multiple times via SMS over the coming weeks and would only ever receive 1 reply from 1 of the techs telling me work was scheduled to be done in "a couple weeks"
8. Get back on the forums and restart the entire process over again with an agent in DM's

Turns out, the first technician never actually opened a work order as far as the Forum support agents could tell and I suspect the last tech that came out likely didn't open a work order either and only actually did so after I suspect the forums support staff directly contacting them (I can't verify this, it's a suspicion based on the messages I got here in DM's at the time).

After a real work order was finally put in, within a few days I get a visit from a tech who I believe was an actual Xfinity employed technician. This new technician asked me where the node delivering my home run was located and after showing him he casually asks about an "Exposed terminal" I had reported... Turns out, the only way to actually get someone qualified to work on the lines/terminals away from the home is to send them a detailed map with pictures showing their terminals wide open to the world with damaged connectors all over the terminal blocks -_-.

I took the tech on a guided tour of the 3 nodes closest to my home and showed him all the terminals and their state of disrepair.

And that was it, he got access to the node in my neighbors back yard, did some work on that and presumably went out and fixed up the other 2 nodes I showed him as they seemed to be closed up now. Because it's an "internal work order", getting any additional details about what was found/done on that work order is not likely as it would apparently require the tech that filed the work order to get that information and share it (and given their history of ghosting i'm not holding my breath on that one).

Unfortunately, I can't say that the issue is 100% resolved since there have been 2 "occurrences" since that last visit a little over a week ago but only 1 of them actively interrupted me (the other happened overnight sometime). That said, I won't be at this residence in 3 months so I've decided the current state of things is tolerable and decided to start wrapping up this journey.

Last month I had asked about compensation for the service outages and was told by the agent that they would need to wait until the issues were resolved before issuing any credits for the service interruption. I decided to not push the issue then and just accepted that answer at the time.

I reached out today to finally get the ball rolling on compensation for all these months of unusable service. To my surprise, the agent comes back and tells me they would be authorizing credit 16 days of service interruptions based on the data they had from the last 30 days... As this issue has been plaguing me since July and was told previously I had to wait for the issue to be resolved to get credit, I declined that offer and pushed back and explained to them how this had been going on for far longer and that I would not accept anything less than a 50% credit for the months I was effected.

It turns out, the data that they use to generate these service credit offers only goes back 30 days and the front line agents cannot override this. Obviously that's not going to be OK so I have now requested that they escalate the service credit request to someone with the authority to authorize credit for outages going back further than 30 days which they have agreed to do which is where we are at the time of this post.

Mainly wanted to share this last bit of information to make others who are potentially facing issues that take longer than 30 days aware of this practice and to be prepared to ask for an escalation to ensure they are compensated properly.