Participant

Intermittent T4 errors SB6141

Usually once or twice a day my SB6141 modem reboots with a T4 error. Sometimes it skips a day. I have 3 TVs, one with a DVR and two with DTAs, and the modem directly connected to a 4-way splitter in the entrance box. Tech grounded the entrance cable and replaced the end on every cable in the house plus the one at the pedestal. He even ran a new cable to one of the TVs.

 

Model Name: SB6141
Vendor Name: ARRIS Group, Inc.
Firmware Name: SB_KOMODO-1.0.7.0-SCM00-NOSH
Boot Version: PSPU-Boot(25CLK)(W) 1.0.12.18m5
Hardware Version: 8.0
Serial Number: 397185624236190001013022
Firmware Build Time: Jul 22 2016 08:13:57

 

This is typically what I see in the log:

 

Jan 01 1970 00:00:17

6-Notice

N/A

Cable Modem Reboot due to T4 timeout ;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 19:46:30

3-Critical

R04.0

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 19:46:25

5-Warning

T202.0

Lost MDD Timeout;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 19:46:21

5-Warning

N/A

DS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 19:46:21

5-Warning

T202.0

Lost MDD Timeout;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 19:46:21

5-Warning

N/A

DS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 19:46:01

3-Critical

T05.0

SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 11:09:27

5-Warning

T202.0

Lost MDD Timeout;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 11:09:27

5-Warning

N/A

DS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 08:50:46

3-Critical

R02.0

No Ranging Response received - T3 time-out;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 16 2017 07:56:52

5-Warning

T202.0

Lost MDD Timeout;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

 

 

Channel ID

16 

15 

24 

26 

10 

12 

14 

Frequency

549000000 Hz 

543000000 Hz 

597000000 Hz 

609000000 Hz 

507000000 Hz 

513000000 Hz 

525000000 Hz 

537000000 Hz 

Signal to Noise Ratio

36 dB 

36 dB 

37 dB 

37 dB 

38 dB 

38 dB 

38 dB 

38 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

-2 dBmV  

-2 dBmV  

-1 dBmV  

-1 dBmV  

-1 dBmV  

-1 dBmV  

-2 dBmV  

-2 dBmV  

 

Upstream

Bonding Channel Value

Channel ID

Frequency

30600000 Hz 

37000000 Hz 

19400000 Hz 

24200000 Hz 

Ranging Service ID

5633 

5633 

5633 

5633 

Symbol Rate

5.120 Msym/sec 

2.560 Msym/sec 

2.560 Msym/sec 

5.120 Msym/sec 

Power Level

44 dBmV 

44 dBmV 

43 dBmV 

44 dBmV 

Upstream Modulation

[3] QPSK
[1] 16QAM
[2] 64QAM
 

[3] QPSK
[1] 16QAM
[2] 64QAM
 

[3] QPSK
[2] 16QAM
 

[3] QPSK
[1] 16QAM
[2] 64QAM
 

Ranging Status

Success 

Success 

Success 

Success 

 

Signal Stats (Codewords)

Bonding Channel Value

Channel ID

16 

15 

24 

26 

10 

12 

14 

Total Unerrored Codewords

244178532 

211098043 

211087003 

211085697 

211012705 

210993779 

210986352 

211030527 

Total Correctable Codewords

120 

185 

157 

88 

199 

177 

335 

442 

Total Uncorrectable Codewords

5755 

5533 

5606 

5580 

5426 

5575 

5257 

5289 

 

Downstream power levels will vary from -4 to 0db

 

As a side note in case it is related, I have an intermittent problem with some TV channels freezing and breaking up - those using freq 153000 & I think 105000, such as channel 6/1200. When the tech replaced the cable ends and ran the new TV cable, the errors stopped. But the last few days they have come back. Looking at my two DTAs today, the Signal-to Noise levels are stable this time but the power levels are fluctuating a lot.

 

 

 

24 REPLIES
Expert

Re: Intermittent T4 errors SB6141

do a factory reset on the modem to try to get the channels all together... It looks like there is ingress on the skipped ones and you're now on channels outside the modems designed capture range.

Ingress is from broadcast tv and is probably the outside cable.

or connectors

 

Participant

Re: Intermittent T4 errors SB6141

So I disconnect the cable so the modem unlocks then I’ll have access to the Reset All Defaults button on the configuration page? Should I do a power reset next?

What’s going to happen when I reconnect the modem? Does TWC have to download something to it and if so, how long will that take? Will I have to call them? Thank you.

Expert

Re: Intermittent T4 errors SB6141

yes, then repower it with the coax connected, It will take a minute or two to auto provision, then when the lights go blue, copy and paste the signal level page here... Let's see if there's serious issues on those channels.

 It doesn't need a call to TWC

 

 

Participant

Re: Intermittent T4 errors SB6141

Here's what I got after the reset. Downstream bonding channels look much cleaner, at least to me.

 

Downstream Bonding Channel Value
Channel ID10 11 12 13 14 15 16 
Frequency507000000 Hz 513000000 Hz 519000000 Hz 525000000 Hz 531000000 Hz 537000000 Hz 543000000 Hz 549000000 Hz 
Signal to Noise Ratio38 dB 38 dB 38 dB 38 dB 38 dB 38 dB 38 dB 38 dB 
Downstream ModulationQAM256 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
0 dBmV  0 dBmV  0 dBmV  0 dBmV  0 dBmV  0 dBmV  0 dBmV  0 dBmV  

 

Upstream Bonding Channel Value
Channel ID
Frequency30600000 Hz 37000000 Hz 19400000 Hz 24200000 Hz 
Ranging Service ID7447 7447 7447 7447 
Symbol Rate5.120 Msym/sec 2.560 Msym/sec 2.560 Msym/sec 5.120 Msym/sec 
Power Level43 dBmV 43 dBmV 43 dBmV 43 dBmV 
Upstream Modulation[3] QPSK
[1] 16QAM
[2] 64QAM
 
[3] QPSK
[1] 16QAM
[2] 64QAM
 
[3] QPSK
[2] 16QAM
 
[3] QPSK
[1] 16QAM
[2] 64QAM
 
Ranging StatusSuccess Success Success Success 

 

Signal Stats (Codewords)Bonding Channel Value
Channel ID10 11 12 13 14 15 16 
Total Unerrored Codewords8153574 7130609 7122163 7138884 7113896 7114963 7113761 7118164 
Total Correctable Codewords10 19 16 13 
Total Uncorrectable Codewords674 1490 1384 1480 1508 1442 1470 1505 
Participant

Re: Intermittent T4 errors SB6141

But I've still had two T4 timeout reboots today.

 

Participant

Re: Intermittent T4 errors SB6141

But no problems with my TV last night. Hopefully that continues.

 

Expert

Re: Intermittent T4 errors SB6141

If it gets wind out and the DS channels drop, the outside cable is bad, connectors corroded, etc. 

 Modem has a decent log of errors compared to cable boxes.... and if DS , RCS or TCS partial service shows up in the log, usually a T4 will follow to try to reset relevel the modem or find good channels. 

On old modems, the channels must be in a narrow bankk, preferably adjacent, the first channel can be in the span of the 8 channels, it's the home one and staggered among modems.

Resetting the modem migh slightly help the cable box if there's corroded connections.. But, those ;loose/corroded connections must be repaired, they drag down everyone on the node.

 

Participant

Re: Intermittent T4 errors SB6141

MsRaye,

My signal levels & error counts look great. Issues with TV channel 6 have disappeared since I did a reset on the SB6141 and it bonded different channels. Just about every cable connector in the house has been replaced including the one at the pedestal. I have one 4-way splitter feeding 4 devices. Two of my four cable runs have been replaced – one TV and the cable modem. You mentioned wind but all cable runs in my development are underground which I guess can have its own issues.

Yet I continue to get 1 – 3 T4 timeouts a day. Is this just something I’m going to have to live with? I’m only at 70MB but would an SB6183 modem work better, as far as having less T4 problems? Here are my latest logs. Thank you.

Downstream

Bonding Channel Value

Channel ID

10 

11 

12 

13 

14 

15 

16 

Frequency

507000000 Hz 

513000000 Hz 

519000000 Hz 

525000000 Hz 

531000000 Hz 

537000000 Hz 

543000000 Hz 

549000000 Hz 

Signal to Noise Ratio

37 dB 

38 dB 

38 dB 

37 dB 

37 dB 

37 dB 

37 dB 

38 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

-1 dBmV  

-1 dBmV  

-1 dBmV  

-2 dBmV  

-2 dBmV  

-2 dBmV  

-3 dBmV  

-2 dBmV  

 

Upstream

Bonding Channel Value

Channel ID

Frequency

30600000 Hz 

37000000 Hz 

19400000 Hz 

24200000 Hz 

Ranging Service ID

Symbol Rate

5.120 Msym/sec 

2.560 Msym/sec 

2.560 Msym/sec 

5.120 Msym/sec 

Power Level

45 dBmV 

45 dBmV 

44 dBmV 

45 dBmV 

Upstream Modulation

[3] QPSK
[1] 16QAM
[2] 64QAM
 

[3] QPSK
[1] 16QAM
[2] 64QAM
 

[3] QPSK
[2] 16QAM
 

[3] QPSK
[1] 16QAM
[2] 64QAM
 

Ranging Status

Success 

Success 

Success 

Success 

 

Signal Stats (Codewords)

Bonding Channel Value

Channel ID

10 

11 

12 

13 

14 

15 

16 

Total Unerrored Codewords

244251523 

243415438 

243407167 

243398985 

243397499 

243398570 

243426247 

243397412 

Total Correctable Codewords

11 

27 

43 

10 

Total Uncorrectable Codewords

1442 

1354 

1432 

1440 

1531 

1449 

1407 

1601 

 

Time

Priority

Code

Message

Sep 22 2017 10:10:09

6-Notice

I401.0

TLV-11 - unrecognized OID;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:10:09

5-Warning

Z00.0

MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;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=20:3d:66:08:45:63;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:17

3-Critical

R06.0

Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:17

3-Critical

R03.0

Ranging Request Retries exhausted;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:17

3-Critical

R06.0

Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:17

3-Critical

R03.0

Ranging Request Retries exhausted;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:17

3-Critical

R06.0

Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:17

3-Critical

R03.0

Ranging Request Retries exhausted;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:16

3-Critical

R06.0

Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:16

3-Critical

R03.0

Ranging Request Retries exhausted;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 10:09:07

3-Critical

R02.0

No Ranging Response received - T3 time-out;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 09:59:41

5-Warning

T202.0

Lost MDD Timeout;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Sep 22 2017 09:59:41

5-Warning

N/A

DS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=20:3d:66:08:45:63;CMTS-MAC=00:17:10:8b:45:26;CM-QOS=1.1;CM-VER=3.0;

Established Sharer

Re: Intermittent T4 errors SB6141

T3 and T4 errors are caused by a loss of signal from the node.  The T3 is a brief dropout of less than three seconds, while a T4 lasts longer and requires the modem to search again for signal on its home channel. 

T3 AND T4 ERRORS ARE NOT A PROBLEM IN YOUR MODEM, despite what the people staffing the tech help phone and chat lines will tell you.  They are often caused by a loose, corroded, or broken connection somewhere along the coaxial trunk lines or fiber optic cable in your neighborhood.  It doesn't matter much if the lines are buried underground or hanging overhead, they all can develop the same types of failures over time. 

If the breaks aren't found and fixed by the home service tech checking from your home to where your drop connects to the main trunk lines, TWC-Spectrum has to schedule a line maintenance crew with a bucket truck.   These guys may be third-party contractors rather than company employees.