U

Visitor

 • 

4 Messages

Tue, Jun 28, 2022 7:03 PM

Motorola MB8611 keeps losing connection and rebooting throughout the day

My modem keeps rebooting throughout the day. I have had 4 different modems and modem/routers in the last 3 years and this continuously keeps happening regardless of what I try. I have rebooted it dozens of times, replaced almost every cable connecting to my system (excluding the ones running through the walls), and changed out various splitters. Normally this wouldn't bother me but I recently started working from home so a stable internet connection is crucial for my work. 

Below are the latest Error Logs, Downstream, and Upstream Channels from about 30 minutes before posting this:

Time 

Priority

Description 

16:18:07
Mon Jun 27 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

16:18:07
Mon Jun 27 2022

Critical (3)

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

16:18:50
Mon Jun 27 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

16:18:50
Mon Jun 27 2022

Critical (3)

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

16:18:51
Mon Jun 27 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

16:18:51
Mon Jun 27 2022

Critical (3)

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

16:19:18
Mon Jun 27 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

16:19:18
Mon Jun 27 2022

Critical (3)

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

16:19:33
Mon Jun 27 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

16:19:34
Mon Jun 27 2022

Critical (3)

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

16:20:18
Mon Jun 27 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

16:20:18
Mon Jun 27 2022

Critical (3)

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

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

16:26:30
Mon Jun 27 2022

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-VER=3.1;

16:26:30
Mon Jun 27 2022

Critical (3)

TFTP Failed - OUT OF ORDER packets;CM-VER=3.1;

16:26:30
Mon Jun 27 2022

Critical (3)

TFTP Request Retries exceeded, CM unable to register

16:26:44
Mon Jun 27 2022

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

10:19:44
Tue Jun 28 2022

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Notice (6)

Honoring MDD; IP provisioning mode = IPv6

11:10:51
Tue Jun 28 2022

Notice (6)

DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-VER=3.1;

   Channel

Lock Status

Modulation

Channel ID

Freq. (MHz)

Pwr (dBmV)

SNR (dB)

Corrected

Uncorrected

   1

Locked

QAM256

20

603.0

-6.4

37.2

0

0

   2

Locked

QAM256

17

585.0

-5.4

37.7

0

0

   3

Locked

QAM256

18

591.0

-5.7

37.8

0

0

   4

Locked

QAM256

19

597.0

-5.8

37.7

0

0

   5

Locked

QAM256

21

609.0

-6.7

37.0

0

0

   6

Locked

QAM256

22

615.0

-6.8

37.0

0

0

   7

Locked

QAM256

23

621.0

-6.3

37.4

0

0

   8

Locked

QAM256

24

627.0

-5.8

37.7

0

0

   9

Locked

QAM256

25

633.0

-6.0

37.8

0

0

   10

Locked

QAM256

26

639.0

-6.4

37.5

0

0

   11

Locked

QAM256

27

645.0

-6.6

37.2

0

0

   12

Locked

QAM256

28

651.0

-7.1

37.0

0

0

   13

Locked

QAM256

29

657.0

-6.4

37.2

0

0

   14

Locked

QAM256

30

663.0

-6.0

37.5

0

0

   15

Locked

QAM256

31

669.0

-5.6

37.9

0

0

   16

Locked

QAM256

32

675.0

-5.7

37.2

0

0

   17

Locked

QAM256

33

681.0

-5.6

37.7

0

0

   18

Locked

QAM256

34

687.0

-5.6

37.5

0

0

   19

Locked

QAM256

35

693.0

-5.7

37.4

0

0

   20

Locked

QAM256

36

699.0

-5.4

37.5

0

0

   21

Locked

QAM256

37

705.0

-5.0

38.0

0

0

   22

Locked

QAM256

38

711.0

-5.1

38.3

0

0

   23

Locked

QAM256

39

717.0

-5.2

38.0

0

0

   24

Locked

QAM256

40

723.0

-6.0

37.6

0

0

   25

Locked

QAM256

41

729.0

-5.9

37.5

0

0

   26

Locked

QAM256

42

735.0

-5.7

37.7

0

0

   27

Locked

QAM256

43

741.0

-5.8

37.8

0

0

   28

Locked

QAM256

44

747.0

-5.3

38.2

0

0

   29

Locked

QAM256

45

753.0

-5.0

38.5

0

0

   30

Locked

QAM256

46

759.0

-5.2

38.3

0

0

   31

Locked

QAM256

47

765.0

-5.9

38.0

0

0

   32

Locked

OFDM PLC

48

805.0

-3.7

38.4

10003812

0

   Channel

Lock Status

Channel Type

Channel ID

Symb. Rate (Ksym/sec)

Freq. (MHz)

Pwr (dBmV)

   1

Locked

SC-QAM

1

2560

10.4

48.3

   2

Locked

SC-QAM

2

5120

16.4

49.0

   3

Locked

SC-QAM

3

5120

22.8

49.5

   4

Locked

SC-QAM

4

5120

29.2

49.8

   5

Locked

SC-QAM

5

5120

35.6

49.8

   6

Locked

SC-QAM

6

2560

40.4

50.3

EG

Expert

 • 

95K Messages

1分前

Both the downstream and the upstream power levels are marginal and they may be intermittently fluctuating even farther to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.

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.


Good luck with it !

Visitor

 • 

4 Messages

@EG​ Thank you very much for replying I really appreciate it! I replaced the two splitters leading to my modem (one outside and one inside) with wideband splitters (5-1670 MHz range). I have a MoCA system on my network so I can have hard-line connections upstairs for my personal computer. I will update if I am still having issues.

Side note: When I replaced the outside splitter I also noticed that I have what appears to be a very old POE filter connected to the splitter's input. I didn't need to install a POE filter for my MoCA system when I installed it a year or so ago so I might also need to replace that with a new one as well. The POE filter is directly upstream from my modem which is why I believe it may be an issue. I can post a full network diagram I have created if needed to show where it is located. 

EG

Expert

 • 

95K Messages

1分前

So what do the signal stat figures look like now ?

Visitor

 • 

4 Messages

@EG

Here are the Downstream, Upstream, and Event Logs from today. I replaced the splitter this morning around 8 after it went out again at about 7:30ish

Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 20 603.0 -6.7 36.8 0 0
   2 Locked QAM256 17 585.0 -5.6 37.6 0 0
   3 Locked QAM256 18 591.0 -5.8 37.7 0 0
   4 Locked QAM256 19 597.0 -6.1 37.6 0 0
   5 Locked QAM256 21 609.0 -6.9 37.0 0 0
   6 Locked QAM256 22 615.0 -7.0 36.9 0 0
   7 Locked QAM256 23 621.0 -6.6 37.3 0 0
   8 Locked QAM256 24 627.0 -6.1 37.6 0 0
   9 Locked QAM256 25 633.0 -6.2 37.8 0 0
   10 Locked QAM256 26 639.0 -6.7 37.5 0 0
   11 Locked QAM256 27 645.0 -7.0 37.2 0 0
   12 Locked QAM256 28 651.0 -7.3 37.0 0 0
   13 Locked QAM256 29 657.0 -6.6 37.2 0 0
   14 Locked QAM256 30 663.0 -6.3 37.5 0 0
   15 Locked QAM256 31 669.0 -5.9 37.8 0 0
   16 Locked QAM256 32 675.0 -5.9 37.5 0 0
   17 Locked QAM256 33 681.0 -5.9 37.6 0 0
   18 Locked QAM256 34 687.0 -6.0 37.4 0 0
   19 Locked QAM256 35 693.0 -6.1 37.4 0 0
   20 Locked QAM256 36 699.0 -5.6 37.5 0 0
   21 Locked QAM256 37 705.0 -5.3 38.0 0 0
   22 Locked QAM256 38 711.0 -5.5 38.1 0 0
   23 Locked QAM256 39 717.0 -5.6 38.1 0 0
   24 Locked QAM256 40 723.0 -6.2 37.7 0 0
   25 Locked QAM256 41 729.0 -6.2 37.5 0 0
   26 Locked QAM256 42 735.0 -6.1 37.7 0 0
   27 Locked QAM256 43 741.0 -6.1 37.8 0 0
   28 Locked QAM256 44 747.0 -5.4 38.2 0 0
   29 Locked QAM256 45 753.0 -5.3 38.5 0 0
   30 Locked QAM256 46 759.0 -5.6 38.2 0 0
   31 Locked QAM256 47 765.0 -6.1 37.9 0 0
   32 Locked OFDM PLC 48 805.0 -4.0 38.4 7649403 0

Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Locked SC-QAM 1 2560 10.4 49.0
   2 Locked SC-QAM 2 5120 16.4 49.3
   3 Locked SC-QAM 3 5120 22.8 49.8
   4 Locked SC-QAM 4 5120 29.2 50.5
   5 Locked SC-QAM 5 5120 35.6 50.5
   6 Locked SC-QAM 6 2560 40.4 50.5

Time 

Priority 

Description 

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

07:49:08
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

07:49:14
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

07:49:20
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

07:51:35
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

07:51:35
Wed Jun 29 2022

Critical (3)

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

07:51:36
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

07:51:37
Wed Jun 29 2022

Critical (3)

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

07:51:42
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

07:51:42
Wed Jun 29 2022

Critical (3)

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

07:53:34
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

07:53:41
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-VER=3.1;

07:53:57
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

07:54:02
Wed Jun 29 2022

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

08:30:38
Wed Jun 29 2022

Critical (3)

SYNC Timing Synchronization failure - Loss of Sync;CM-VER=3.1;

08:30:47
Wed Jun 29 2022

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-VER=3.1;

Time Not Established

Notice (6)

Honoring MDD; IP provisioning mode = IPv6

11:33:23
Wed Jun 29 2022

Notice (6)

DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-VER=3.1;

11:33:44
Wed Jun 29 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-VER=3.1;

EG

Expert

 • 

95K Messages

1分前

It's still N/G. If there is nothing more that can be done to improve the connection quality, then you'll need a tech visit as stated. 

Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home. And if the problem is found to be on their side of the demarcation point, there will not be any charge.


Good luck !

Visitor

 • 

4 Messages

@EG​ I appreciate you trying to help me solve this. I will contact Xfinity this week and see when they can get someone out here to take a look. 

Thanks!

XfinityDaryl

Official Employee

 • 

530 Messages

@user_379362

 

Thank you for sharing your experience with us in the Forums. I see that you have been given some great advice from EG. If you need to set up a technician appointment, we are happy to accomodate. If you would like to set that up through here, just send us a direct message with your full name and address. You can send us a direct message but making sure you are first logged in to the Forums. After that, click on the "Chat" icon in the upper right (left of the notification bell), next click on the "pen/pad" icon, and lastly choose Xfinity Support. Thank you again for the time you have spent sharing your situation. 

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.
Was your question answered? Please, mark a reply as the Accepted Answer.tick
EG

Expert

 • 

95K Messages

@user_379362​ Quite welcome !

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? Please mark an Accepted Answer!tick
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