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Very slow speed, MDD message timeout, SYNC Timing Synchronization failure - Loss of Sync

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New Poster

Very slow speed, MDD message timeout, SYNC Timing Synchronization failure - Loss of Sync

Hi there - I've been having incredibly slow speeds for a month. Hovers between 35-50 mbps. Called Xfinity, Called Arris Surfboard..Both say its the other sides issue. Powercycled and it corrects a little and then drops again. Don't know what any of this means, but hoping some good samaritan can help me figure this out. Is it a signal issue or modem issue? 

 

What can I do to correct?

 

Please help! 
TheOtherNaomiWatts

 

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked QAM256 9 513000000 Hz -3.6 dBmV 38.4 dB 0 0
2 Locked QAM256 10 519000000 Hz -2.3 dBmV 38.6 dB 0 0
3 Locked QAM256 11 525000000 Hz -2.2 dBmV 29.6 dB 313137 72
4 Locked QAM256 12 531000000 Hz -2.5 dBmV 26.7 dB 10637240 1645804
5 Locked QAM256 13 543000000 Hz -0.6 dBmV 33.4 dB 5 0
6 Locked QAM256 14 549000000 Hz -0.4 dBmV 39.0 dB 0 0
7 Locked QAM256 15 555000000 Hz -1.4 dBmV 39.0 dB 1 0
8 Locked QAM256 16 561000000 Hz -2.2 dBmV 39.0 dB 0 0

 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 2 5120 Ksym/sec 23700000 Hz 39.8 dBmV
2 Locked ATDMA 1 5120 Ksym/sec 17300000 Hz 39.8 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 30100000 Hz 39.8 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 36500000 Hz 39.8 dBmV

Status - Event Log

The table below contains the log of events that the SBG6700-AC has detected. This log can be important to the service provider to help diagnose and correct problems, if any should occur.

 
Time Priority Description
Thu May 21 18:37:25 2020 Warning (5) MDD message timeout;CM-MAC={Removed};CMTS-MAC={Removed};CM-QOS=1.1;CM-VER=3.0;
Thu May 21 18:26:57 2020 Warning (5) Unicast DSID PSN startup error
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv6
Time Not Established Notice (6) WiFi Interface [wl1] set to Channel 149 (Side-Band Channel:N/A) - Reason:INIT
Time Not Established Notice (6) WiFi Interface [wl0] set to Channel 11 (Side-Band Channel:N/A) - Reason:INIT
Thu May 21 10:24:48 2020 Critical (3) Resetting the cable modem due to docsDevResetNow
Fri May 01 11:54:26 2020 Critical (3) SYNC Timing Synchronization failure - Loss of Sync;CM-MAC={Removed};CMTS-MAC={Removed};CM-QOS=1.1;CM-VER=3.0;
Tue Apr 28 02:32:02 2020 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC={Removed};CMTS-MAC={Removed};CM-QOS=1.1;CM-VER=3.0;
Tue Apr 28 02:17:13 2020 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC={Removed};CMTS-MAC={Removed};CM-QOS=1.1;CM-VER=3.0;

 
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Diamond Problem Solver

Re: Very slow speed, MDD message timeout, SYNC Timing Synchronization failure - Loss of Sync

Out of the 8 downstream signals that your modem has , ch’s 3,4 and 5 have noise/SNR issues. Clean those up and then test. You may need a tech out

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Expert

Re: Very slow speed, MDD message timeout, SYNC Timing Synchronization failure - Loss of Sync

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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I am a Customer Expert volunteering my time to help other customers here in the Forums.
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New Poster

Re: Very slow speed, MDD message timeout, SYNC Timing Synchronization failure - Loss of Sync

Thanks so much for the responses. There are no splitters. I have the modem directly connected to the one active coaxial in the condo.  Can you give me some ideas on how to "reduce noise" on the channels that have too much of it ?


Naomi

New Poster

Re: Very slow speed, MDD message timeout, SYNC Timing Synchronization failure - Loss of Sync

Any ideas on how to reduce noise on those channels? Not sure how to do so but able and willing!
Naomi

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Expert

Re: Very slow speed, MDD message timeout, SYNC Timing Synchronization failure - Loss of Sync

If none of those tips helps, then your only choice is to get a tech out to investigate. 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? Mark the post as Best Answer!