U

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5 Messages

Friday, March 8th, 2024 1:48 PM

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internet-going-inout-due-to-sync-timing-synchronization-failure-failed-to-acquire-qamqpsk-symbol-timing

It looks like I am suddenly having the same modem issues as many others. No problems for 2 1/2 years and now every day for the past week my internet is dropping. Here is the Event Log I am seeing. Any help would be greatly appreciated. 

Event Log  
  
    Time    Priority    Description 
    08:33:15
Mon Dec 18 2023
  Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    11:59:58
Mon Dec 18 2023
  Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    12:00:32
Mon Dec 18 2023
  Critical (3)   No Ranging Response received - T3 time-out;
    12:00:32
Mon Dec 18 2023
  Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;
    12:00:52
Mon Dec 18 2023
  Critical (3)   No Ranging Response received - T3 time-out;
    16:21:18
Mon Dec 18 2023
  Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    16:21:27
Mon Dec 18 2023
  Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    16:22:25
Mon Dec 18 2023
  Critical (3)   No Ranging Response received - T3 time-out;
    16:23:02
Mon Dec 18 2023
  Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;
    16:23:05
Mon Dec 18 2023
  Critical (3)   Started Unicast Maintenance Ranging - No Response received - T3 time-out;
    Time Not Established   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;
    Time Not Established   Notice (6)   Honoring MDD; IP provisioning mode = IPv6
    16:20:27
Thu Mar 7 2024
  Notice (6)   DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.
    16:20:32
Thu Mar 7 2024
  Warning (5)   REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;
    16:20:32
Thu Mar 7 2024
  Warning (5)   RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;
    16:20:32
Thu Mar 7 2024
  Warning (5)   Dynamic Range Window violation
    16:55:07
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    16:55:38
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    16:55:47
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    16:56:15
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    16:56:29
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    16:57:00
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    17:27:45
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    17:28:17
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    17:35:53
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    17:36:21
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    18:03:48
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    18:04:15
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    20:42:25
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    20:42:56
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    22:59:04
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 16; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;
    22:59:32
Thu Mar 7 2024
  Notice (6)   CM-STATUS message sent. Event Type Code: 24; Chan ID: 159; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 3.;

Visitor

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5 Messages

1 year ago

Here's the low down with a Motorola MB8611

Startup Sequence    
   Startup Step Status Comment

  
   Acquire Downstream Channel 643750000 Hz Locked
  
   Upstream Connection OK Operational
  
   Boot State OK Operational

  
   Configuration File OK
  
   Security Enabled BPI+
  


   Connection Status    
   System Up Time 0 days 16h:43m:28s  
  
   Network Access Allowed  
  


   Downstream Bonded Channels  
  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 33 643.8 -18.7 34.2 51 0
   2 Locked QAM256 9 499.8 -19.3 34.0 115 0
   3 Locked QAM256 10 505.8 -19.1 33.9 122 0
   4 Locked QAM256 11 511.8 -19.1 34.1 121 0
   5 Locked QAM256 12 517.8 -18.5 34.6 112 0
   6 Locked QAM256 13 523.8 -18.5 34.3 101 0
   7 Locked QAM256 14 529.8 -19.2 34.0 119 0
   8 Locked QAM256 15 535.8 -19.5 33.7 115 0
   9 Locked QAM256 16 541.8 -19.5 33.7 120 0
   10 Locked QAM256 17 547.8 -18.2 34.7 90 0
   11 Locked QAM256 18 553.8 -18.3 34.7 94 0
   12 Locked QAM256 19 559.8 -19.9 31.8 196 0
   13 Locked QAM256 20 565.8 -20.5 30.3 5461 0
   14 Locked QAM256 21 571.8 -20.0 33.3 118 0
   15 Locked QAM256 22 577.8 -17.9 34.7 82 0
   16 Locked QAM256 23 583.8 -18.7 33.8 76 0
   17 Locked QAM256 24 589.8 -20.2 32.7 85 0
   18 Locked QAM256 25 595.8 -19.7 32.6 227 0
   19 Locked QAM256 26 601.8 -18.8 31.5 113 0
   20 Locked QAM256 27 607.8 -18.1 34.8 54 0
   21 Locked QAM256 28 613.8 -18.9 34.1 53 0
   22 Locked QAM256 29 619.8 -19.4 33.4 66 0
   23 Locked QAM256 30 625.8 -19.2 33.8 57 0
   24 Locked QAM256 31 631.8 -19.0 33.9 49 0
   25 Locked QAM256 32 637.8 -19.1 34.0 45 0
   26 Locked QAM256 34 649.8 -19.7 33.5 46 0
   27 Locked QAM256 35 655.8 -20.1 33.1 69 0
   28 Locked QAM256 36 661.8 -20.9 32.7 63 0
   29 Locked QAM256 37 667.8 -19.3 33.9 35 0
   30 Locked QAM256 38 673.8 -18.9 34.2 40 0
   31 Locked QAM256 39 679.8 -20.2 33.3 33 0
   32 Locked QAM256 40 685.8 -20.2 33.2 43 0
   33 Locked OFDM PLC 159 699.0 -17.4 33.8 1041153857 816


   Upstream Bonded Channels  
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Locked SC-QAM 10 5120 16.4 46.5
   2 Locked SC-QAM 11 5120 22.8 47.0
   3 Locked SC-QAM 12 5120 29.2 47.0
   4 Locked SC-QAM 13 5120 35.6 47.0
   5 Locked SC-QAM 14 2560 40.4 47.5

Gold Problem Solver

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26.5K Messages

1 year ago

Here's the low down with a Motorola MB8611 ...

Whoosh! All the downstream power levels and SNR values are way out of spec (too low). This usually indicates a problem with the link between your modem and Comcast's network, and is likely responsible for most of the event log entries as well. The cause is often poor coax connections or damaged coax cable, usually in or near your home. Running the cable through a surge protector, a defective splitter, or too many splitters can cause signal problems as well. If there is an amplifier in the line make sure it's getting power. 

If you want to troubleshoot this yourself, please see Internet Troubleshooting Tips.

If you can't find the problem or you'd rather have Comcast take care of it and an employee does not respond to your message here, call them at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. It's not likely they can fix the problem remotely. If not, insist they send a tech out to identify the cause and correct it.

If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit (approx $100) unless you have their Service Protection Plan ( https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device or anything outside your home you shouldn't be charged.

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

Gold Problem Solver

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26.5K Messages

1 year ago

... Technician came and changed the splitter out. Everything was working just fine until now ...

Unfortunately connection problems are often intermittent and hard to track down, but $100 billion dollar corporations have lots of resources they can bring to bear if properly motivated. If Internet Troubleshooting Tips doesn't help you are pretty much stuck with leaning on Comcast until they figure out the problem and correct it. If an employee does not respond to your message here, keep at them until they provide competent technical help for the trouble you are having. The page at https://www.xfinity.com/hub/customer-experience/xfinity-customer-care-update which links to the "contact me/Send Tom Feedback" form at https://support.xfinity.com/svp-contact-form and might be worth a try.

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

Visitor

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5 Messages

1 year ago

Thanks again @BruceW .  Another technician came by and replaced some wiring on the outside of the house. Seems like things are working now...

Official Employee

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3.4K Messages

user_b0a114 I'm happy to hear that our expert technicians were able to get your services working well for you again. I hope you have a great rest of your day!
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.
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