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Friday, October 18th, 2024 2:15 AM

SYNC Timing Synchronization Failure

As you may expect my Xfinity connection is frequently dropping throughout the day because of this issue. It's been happening since August and just recently Xfinity buried a new cable, replaced an amplifier, and tested all levels to spec. It was solid for a week but the SYNC issues continue. I went as far as replacing the modem originally a Motorola to an Arris but the issue persists. The Sync error is leaving the modem completely unreachable. Even from within my own network, I can't ping it, log in, or anything. It never receives a request to reboot. It has to be manually unplugged every time it crashes. Below is the log and the power levels. 

31/12/1969

19:00:20

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-9, 5-42MHz.

31/12/1969

19:00:25

3

No Ranging Response received - T3 time-out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

31/12/1969

19:00:40

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.

31/12/1969

19:00:40

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.

31/12/1969

19:00:40

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.

31/12/1969

19:00:16

3

CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.

31/12/1969

19:00:19

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

31/12/1969

19:00:21

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-9, 5-42MHz.

31/12/1969

19:00:25

3

No Ranging Response received - T3 time-out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

31/12/1969

19:00:38

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.

31/12/1969

19:00:38

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.

31/12/1969

19:00:38

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.

31/12/1969

19:00:15

3

CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.

31/12/1969

19:00:19

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

31/12/1969

19:00:20

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-9, 5-42MHz.

31/12/1969

19:00:23

3

No Ranging Response received - T3 time-out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

31/12/1969

19:00:36

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.

31/12/1969

19:00:36

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.

31/12/1969

19:00:36

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.

16/10/2024

11:37:29

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:37:35

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:39:16

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:39:17

3

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:39:17

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:39:18

3

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:39:18

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:39:18

3

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:39:21

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:39:21

3

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:40:04

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

11:40:07

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-9, 5-42MHz.

16/10/2024

11:40:21

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.

16/10/2024

11:40:21

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.

16/10/2024

11:40:21

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.

31/12/1969

19:00:16

3

CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.

31/12/1969

19:00:20

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

31/12/1969

19:00:22

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-9, 5-42MHz.

31/12/1969

19:00:25

3

No Ranging Response received - T3 time-out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

31/12/1969

19:00:41

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.

31/12/1969

19:00:41

3

CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.

31/12/1969

19:00:41

3

CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.

16/10/2024

14:11:01

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

14:11:05

3

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

16/10/2024

14:13:37

3

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx;CMTS-MAC=xx;CM-QOS=1.1;CM-VER=3.1;

Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
17 Locked QAM256 519000000 Hz 4 dBmV 41 dB 0 0
1 Locked QAM256 417000000 Hz 5 dBmV 42 dB 0 0
2 Locked QAM256 423000000 Hz 5 dBmV 42 dB 0 0
3 Locked QAM256 429000000 Hz 5 dBmV 42 dB 0 0
4 Locked QAM256 435000000 Hz 5 dBmV 42 dB 0 0
5 Locked QAM256 441000000 Hz 5 dBmV 42 dB 0 0
6 Locked QAM256 447000000 Hz 5 dBmV 42 dB 0 0
7 Locked QAM256 453000000 Hz 5 dBmV 42 dB 0 0
8 Locked QAM256 459000000 Hz 5 dBmV 42 dB 0 0
9 Locked QAM256 465000000 Hz 5 dBmV 42 dB 0 0
10 Locked QAM256 471000000 Hz 5 dBmV 42 dB 0 0
11 Locked QAM256 477000000 Hz 5 dBmV 41 dB 0 0
12 Locked QAM256 483000000 Hz 5 dBmV 42 dB 0 0
13 Locked QAM256 489000000 Hz 5 dBmV 42 dB 0 0
14 Locked QAM256 495000000 Hz 5 dBmV 41 dB 0 0
15 Locked QAM256 507000000 Hz 5 dBmV 41 dB 0 0
16 Locked QAM256 513000000 Hz 5 dBmV 41 dB 0 0
18 Locked QAM256 525000000 Hz 4 dBmV 41 dB 0 0
19 Locked QAM256 531000000 Hz 5 dBmV 41 dB 0 0
20 Locked QAM256 537000000 Hz 4 dBmV 41 dB 0 0
21 Locked QAM256 543000000 Hz 4 dBmV 41 dB 0 0
22 Locked QAM256 549000000 Hz 4 dBmV 41 dB 0 0
23 Locked QAM256 561000000 Hz 4 dBmV 41 dB 0 0
24 Locked QAM256 567000000 Hz 4 dBmV 41 dB 0 0
25 Locked OFDM PLC 693000000 Hz 5 dBmV 40 dB 20207399 0
26 Locked QAM256 573000000 Hz 4 dBmV 41 dB 0 0
27 Locked QAM256 579000000 Hz 4 dBmV 41 dB 0 0
28 Locked QAM256 585000000 Hz 4 dBmV 41 dB 0 0
29 Locked QAM256 591000000 Hz 4 dBmV 41 dB 0 0
30 Locked QAM256 597000000 Hz 4 dBmV 41 dB 0 0
31 Locked QAM256 603000000 Hz 5 dBmV 41 dB 0 0
32 Locked QAM256 609000000 Hz 4 dBmV 41 dB 0 0


Upstream Bonded Channels
Channel ID Lock Status US Channel Type Frequency Width Power
6 Locked SC-QAM 16300000 Hz 6400000 46.5 dBmV
7 Locked SC-QAM 22800000 Hz 6400000 46.5 dBmV
8 Locked SC-QAM 29200000 Hz 6400000 45.8 dBmV
11 Locked SC-QAM 35600000 Hz 6400000 45.0 dBmV
12 Locked SC-QAM 40400000 Hz 3200000 44.5 dBmV




Official Employee

 • 

1.7K Messages

16 days ago

 

fathornet25 Thank you so much for using our Forums and we appreciate you letting us know about these connection issues so we can help get them working properly for you. To get started can you please send us a DM with your name and address? Here's the detailed steps to direct message us: 
• Click "Sign In" if necessary 
• Click the "Direct Message" icon (upper right corner of this page) 
• Click the "New message" (pencil and paper) icon 
• Type "Xfinity Support" in the to line and select "Xfinity Support" from the drop-down list 
• Type your message in the text area near the bottom of the window 
• Press Enter to send your message
 
 

 

Expert

 • 

106.9K Messages

16 days ago

@XfinityJorge 

Why does this have to go private at this point ? That kind of defeats the purpose of a public help forum such as this is, no ?... Why not ask some general self troubleshooting things first which is in keeping with the intent of what these public help forums were designed for so that all readers here may benefit. 

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