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Modem keeps resetting.

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Frequent Visitor

Modem keeps resetting.

Internet has been failing repeatedly all day.  800 number is useless as it gets hung up trying to access the modem.  Observing things I can see that the modem is actually resetting.  Going to it with the browser shows:

 

Cable Modem
Status Signal Addresses Configuration Logs Open Source Help
This page displays detailed information intended for use by an authorized ARRIS Group, Inc. Cable Modem technician.

 

Time Priority Code Message
Mar 15 2020 21:33:56 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:17 6-Notice N/A Cable Modem Reboot due to T4 timeout ;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:33:01 3-Critical R04.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:31:06 6-Notice N/A MDD Recovery following MDD Loss;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:31:00 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:31:00 6-Notice N/A MDD Recovery following MDD Loss;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:30:50 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:29:21 5-Warning T202.0 Lost MDD Timeout;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:28:58 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:28:56 6-Notice N/A MDD Recovery following MDD Loss;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:28:54 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:28:35 5-Warning T202.0 Lost MDD Timeout;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:28:10 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:09:46 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:17 6-Notice N/A Cable Modem Reboot due to power reset ;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:05:00 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:18 6-Notice N/A Cable Modem Reboot due to IP loss ;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 20:58:19 6-Notice N/A MDD Recovery following MDD Loss;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 20:58:15 3-Critical R02.0 No Ranging Response received - T3 time-out;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 20:58:08 5-Warning T202.0 Lost MDD Timeout;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;

 


 

 

 

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Frequent Visitor

Re: Modem restarts constantly

Mine is currently doing the same thing.  Log contains entries like:

Jan 01 1970 00:00:17 6-Notice N/A Cable Modem Reboot due to T4 timeout ;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 21:33:01 3-Critical R04.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
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Frequent Visitor

Re: Modem keeps resetting.

Mar 15 2020 22:00:35 6-Notice N/A MDD Recovery following MDD Loss;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:25 5-Warning T202.0 Lost MDD Timeout;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:23 5-Warning N/A DS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:23 5-Warning T202.0 Lost MDD Timeout;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:23 5-Warning N/A DS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:23 5-Warning T202.0 Lost MDD Timeout;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:23 5-Warning N/A DS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:23 5-Warning T202.0 Lost MDD Timeout;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:23 5-Warning N/A DS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
Mar 15 2020 22:00:10 3-Critical T05.0 SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=38:6b:bb:e0:a6:88;CMTS-MAC=04:2a:e2:c6:b8:ea;CM-QOS=1.1;CM-VER=3.0;
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Expert

Re: Modem keeps resetting.

Please also post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.




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Frequent Visitor

Re: Modem keeps resetting.

Channel ID
Frequency 477000000 Hz  453000000 Hz  459000000 Hz  465000000 Hz  471000000 Hz  483000000 Hz  489000000 Hz  495000000 Hz 
Signal to Noise Ratio 30 dB  29 dB  27 dB  26 dB  29 dB  28 dB  28 dB  27 dB 
Downstream Modulation QAM256  QAM256  QAM256  QAM256  QAM256  QAM256  QAM256  QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
-10 dBmV   -8 dBmV   -8 dBmV   -10 dBmV   -10 dBmV   -9 dBmV   -8 dBmV   -8 dBmV  

 

Upstream Bonding Channel Value
Channel ID
Frequency 17300000 Hz  23700000 Hz  30100000 Hz  36500000 Hz 
Ranging Service ID 76  76  76  76 
Symbol Rate 5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec 
Power Level 46 dBmV  46 dBmV  46 dBmV  46 dBmV 
Upstream Modulation [2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
Ranging Status Success  Success  Success  Success 

 

Signal Status (Codewords) Bonding Channel Value
Channel ID
Total Unerrored Codewords 2316319  2288676  2107302  128053  2288215  2207430  2203548  2283437 
Total Correctable Codewords 19720  26492  50441  15051  26665  42847  40909  18732 
Total Uncorrectable Codewords 29904  50447  203847  66978  52226  108025  114203  64032 
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Frequent Visitor

Re: Modem restarts constantly

Channel ID
Frequency 477000000 Hz  453000000 Hz  459000000 Hz  465000000 Hz  471000000 Hz  483000000 Hz  489000000 Hz  495000000 Hz 
Signal to Noise Ratio 30 dB  29 dB  27 dB  26 dB  29 dB  28 dB  28 dB  27 dB 
Downstream Modulation QAM256  QAM256  QAM256  QAM256  QAM256  QAM256  QAM256  QAM256 
Power Level
The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
-10 dBmV   -8 dBmV   -8 dBmV   -10 dBmV   -10 dBmV   -9 dBmV   -8 dBmV   -8 dBmV  

 

Upstream Bonding Channel Value
Channel ID
Frequency 17300000 Hz  23700000 Hz  30100000 Hz  36500000 Hz 
Ranging Service ID 76  76  76  76 
Symbol Rate 5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec  5.120 Msym/sec 
Power Level 46 dBmV  46 dBmV  46 dBmV  46 dBmV 
Upstream Modulation [2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
[2] QPSK
[1] 16QAM
[3] 64QAM
 
Ranging Status Success  Success  Success  Success 

 

Signal Status (Codewords) Bonding Channel Value
Channel ID
Total Unerrored Codewords 2316319  2288676  2107302  128053  2288215  2207430  2203548  2283437 
Total Correctable Codewords 19720  26492  50441  15051  26665  42847  40909  18732 
Total Uncorrectable Codewords 29904  50447  203847  66978  52226  108025  114203 

64032 

 

 

 

 

 

 

 

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Frequent Visitor

Re: Modem restarts constantly

Model Name: SB6141
Vendor Name: ARRIS Group, Inc.
Firmware Name: SB_KOMODO-1.0.7.3-SCM02-NOSH
Boot Version: PSPU-Boot(25CLK) 1.0.12.18m3
Hardware Version: 7.0
Serial Number: 374781234522738809020022
Firmware Build Time: Apr 22 2019 15:16:24

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Diamond Problem Solver

Re: Modem restarts constantly

Post downstream power levels too, you keep posting upstream

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Frequent Visitor

Re: Modem restarts constantly

Thanks for helping.  Thought I posted the entire signals page.

 

-10 dBmV   -8 dBmV   -8 dBmV   -10 dBmV   -10 dBmV   -9 dBmV   -8 dBmV   -8 dBmV  
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Frequent Visitor

Re: Modem restarts constantly

Just installed new Arris T25 and activated via comcast.  Hopefully this either corrects it or is more resilient than the old modem.

Highlighted
Expert

Re: Modem restarts constantly

The downstream power is too low and it may be intermittently fluctuating even lower to out of spec levels. The SNR's are also too low  / out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.

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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Frequent Visitor

Re: Modem restarts constantly

thanks for the follow-up.  The new T25 is also failing though seems to be a bit more resilient that the old combination.


I just did factor a splitter out of my basement config.  Hopefully that helps stabilize things.

 

I've got the Modem status page up as often as I can.  I noticed a significant delay (where historically it'd reboot and be out for 5+ minutes).  The modem survived this time but with a huge spike in uncorrectable errors:

 

Downstream QAM

  DCID Freq Power SNR Modulation Octets Correcteds Uncorrectables
Downstream 1 1 453.00 MHz -6.80 dBmV 38.98 dB 256QAM 152150881 339 9147
Downstream 2 2 459.00 MHz -7.10 dBmV 37.64 dB 256QAM 70725 231 10473
Downstream 3 3 465.00 MHz -9.10 dBmV 37.36 dB 256QAM 82546 96 6485
Downstream 4 4 471.00 MHz -9.20 dBmV 38.61 dB 256QAM 94361 179 8078
Downstream 5 5 477.00 MHz -9.50 dBmV 38.61 dB 256QAM 142870 589 6272
Downstream 6 6 483.00 MHz -10.10 dBmV 37.36 dB 256QAM 88614 219 10517
Downstream 7 7 489.00 MHz -9.90 dBmV 37.36 dB 256QAM 82211 255 11151
Downstream 8 8 495.00 MHz -9.10 dBmV 38.61 dB 256QAM 83913 231 11063
Downstream 9 9 501.00 MHz -8.10 dBmV 38.61 dB 256QAM 117055 8052 43231
Downstream 10 10 507.00 MHz -7.40 dBmV 38.98 dB 256QAM 38454 163155 799906
Downstream 11 11 513.00 MHz -8.00 dBmV 38.61 dB 256QAM 40350 244555 670623
Downstream 12 12 519.00 MHz -8.30 dBmV 38.98 dB 256QAM 32866 13197 18794
Downstream 13 13 525.00 MHz -8.00 dBmV 38.98 dB 256QAM 114451 533474 397547
Downstream 14 14 531.00 MHz -10.00 dBmV 38.98 dB 256QAM 33514 258 0
Downstream 15 15 537.00 MHz -10.90 dBmV 37.64 dB 256QAM 25691 686 0
Downstream 16 16 543.00 MHz -9.80 dBmV 38.98 dB 256QAM 32819 145 0
Downstream 17 17 549.00 MHz -9.70 dBmV 38.98 dB 256QAM 107061 3380 0
Downstream 18 18 555.00 MHz -9.60 dBmV 38.98 dB 256QAM 19381 369 0
Downstream 19 19 567.00 MHz -9.00 dBmV 38.98 dB 256QAM 32171 28 0
Downstream 20 20 573.00 MHz -9.40 dBmV 38.61 dB 256QAM 22224 0 0
Downstream 21 21 579.00 MHz -10.40 dBmV 38.61 dB 256QAM 106900 0 0
Downstream 22 22 585.00 MHz -11.40 dBmV 37.36 dB 256QAM 13923 7 36
Downstream 23 23 591.00 MHz -12.30 dBmV 37.36 dB 256QAM 24153 0 1
Downstream 24 24 597.00 MHz -13.40 dBmV 36.61 dB 256QAM 17035 0 1
Downstream 25 25 603.00 MHz -14.50 dBmV 36.39 dB 256QAM 109837 0 0
Downstream 26 26 609.00 MHz -14.00 dBmV 36.61 dB 256QAM 19464 1 0
Downstream 27 27 615.00 MHz -13.50 dBmV 36.61 dB 256QAM 29395 10 0
Downstream 28 28 621.00 MHz -13.60 dBmV 36.61 dB 256QAM 21113 3 0
Downstream 29 29 627.00 MHz -13.20 dBmV 36.61 dB 256QAM 108365 4 0
Downstream 30 30 633.00 MHz -13.90 dBmV 36.39 dB 256QAM 25647 7 0
Downstream 31 31 639.00 MHz -14.50 dBmV 36.39 dB 256QAM 24976 0 0
Downstream 32 32 645.00 MHz -15.00 dBmV 35.60 dB 256QAM 24760 0 0
Highlighted
Expert

Re: Modem restarts constantly

The SNR's are better but some of those downstreams are still way out of spec. More work needs to be done ! It may be best to get a tech out to investigate / correct things. 

 

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.

Good luck !



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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!
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Frequent Visitor

Re: Modem restarts constantly

Comcast tech coming out tomorrow afternoon.  We'll see how that goes.  I'll make sure to pass on your evaluation of the downstream numbers.

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New Poster

Re: Modem restarts constantly

Was the problem resolved and how was it resolved? I've got glitchy service, looked at the modem status and it's normal so I think my cable line is a possibility.