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Constant intermittent DS Partial Service Fallback: MDD Lost errors

 Cary, NC 27513. Single family home. Internet only service - 50/5.

 SB6141 with Firmware SB_KOMODO-1.0.6.14-SCM01-NOSH.  

At the time i started troubleshooting I was having to reboot modem 4-6 times a day since download speed reached 1 MB. 

 

Spent a lot of time reading in forums. Wiring check found RG6 attached to cable drop outside house went to a 2-way twc splitter: 1 line ran direct to wall port/modem and 1 with cut cable attached.

 

Here are all the attempts I have made to fix problem:

1) I removed the splitter and put in a new 1 ghz f-splice adapter. Tighted All Fconnections  (modem, splice, outside house) with 7/16 wrench

Result: Less frequent DS partial Service Fallback errors but still too many. Reboot 2-3 times per day

 

2) Bypassed wallport and attached RG6 from crawl directly to modem

Result: No different

 

3) Realized my line was not grounded to house so i took splitter from 1) above and attached it to cable drop, terminated the 2nd split with F-port terminator, connected the 10 gauge copper wire to ground of splitter (cut old end off and restripped for fresh copper). Tightened connections with 7/16 wrench and put cover back on wall service box. 

Result: Even less frequent DS partial Service Fallback errors but still present. Reboot once daily 

 

4) worked with TWC over chat yesterday and today. they did the standard resending of signal to modem, had me restart cable modem, call if errors show back up and the will send tech. Initated chat today only to go through same protocol and was disconnected from chat before getting tech scheduled. 

 

5) in effort to rule out my house wiring I removed splitter and connected my modem directly  to cable drop outside house. I am not sure if this is a valid test or not.

Result: Similar results on the signal page for DS (but higher power levels ( 5 or 6 vs.  0/-1/-2) Upstream Power was significantly lower

 

Do I need to do anything further or am I right to insist a technician be dispatched? 

 (note: removed 0's from frequency due to exceeding max characters for post)

Signals after grounding with splitter

 

Downstream

Bonding Channel Value

Channel ID

17 

19 

20 

23 

25 

28 

30 

Frequency

555 Hz 

567 Hz 

573 Hz 

591 Hz 

603 Hz 

621 Hz 

633 Hz 

Signal to Noise Ratio

38 dB 

39 dB 

39 dB 

38 dB 

38 dB 

38 dB 

38 dB 

Downstream Modulation

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

Power Level

 


 

0 dBmV  

0 dBmV  

0 dBmV  

0 dBmV  

0 dBmV  

-1 dBmV  

-2 dBmV  

 

Upstream

Bonding Channel Value

Channel ID

Frequency

370Hz 

242 Hz 

306 Hz 

194 Hz 

Ranging Service ID

3180 

3180 

3180 

3180 

Symbol Rate

2.560 Msym/sec 

5.120 Msym/sec 

5.120 Msym/sec 

2.560 Msym/sec 

Power Level

42 dBmV 

39 dBmV 

41 dBmV 

39 dBmV 

Upstream Modulation

[3] QPSK
[3] 16QAM
 

[3] QPSK
[1] 16QAM
[2] 64QAM
 

[3] QPSK
[1] 16QAM
[2] 64QAM
 

[3] QPSK
[2] 16QAM
 

Ranging Status

Suc 

Suc 

Suc 

Suc 

  

Signal Stats (Codewords)

Bonding Channel Value

Channel ID

17 

19 

20 

23 

25 

28 

30 

Total Unerrored Codewords

5724174425 

5698199701 

5698226458 

4817772573 

4921802913 

4921795115 

4248119099 

Total Correctable Codewords

163 

159 

154 

277 

442 

601 

411 

Total Uncorrectable Codewords

531 

1181 

1235 

3390 

2641 

5038 

27481 

 

Singals from modem connected directly to cable drop outside house

  

Downstream

Bonding Channel Value

Channel ID

17 

18 

19 

20 

21 

22 

23 

24 

Frequency

555 Hz 

561 Hz 

567 Hz 

573 Hz 

579 Hz 

585 Hz 

591 Hz 

597 Hz 

Signal to Noise Ratio

38 dB 

39 dB 

39 dB 

39 dB 

38 dB 

39 dB 

39 dB 

39 dB 

Downstream Modulation

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

QAM256 

Power Level

5 dBmV  

6 dBmV  

6 dBmV  

6 dBmV  

6 dBmV  

5 dBmV  

5 dBmV  

6 dBmV  

 

Upstream

Bonding Channel Value

Channel ID

Frequency

37 Hz 

242 Hz 

306 Hz 

194 Hz 

Ranging Service ID

1285 

1285 

1285 

1285 

Symbol Rate

2.560 Msym/sec 

5.120 Msym/sec 

5.120 Msym/sec 

2.560 Msym/sec 

Power Level

39 dBmV 

36 dBmV 

37 dBmV 

35 dBmV 

Upstream Modulation

[3] QPSK
[3] 16QAM
 

[3] QPSK
[1] 16QAM
[2] 64QAM
 

[3] QPSK
[1] 16QAM
[2] 64QAM
 

[3] QPSK
[2] 16QAM
 

Ranging Status

Suc 

Suc 

Suc 

Suc 

  

Signal Stats (Codewords)

Bonding Channel Value

Channel ID

17 

18 

19 

20 

21 

22 

23 

24 

Total Unerrored Codewords

22141390 

21141542 

21149616 

21156946 

21131000 

21132961 

21131839 

21134573 

Total Correctable Codewords

28 

13 

13 

15 

16 

Total Uncorrectable Codewords

1369 

486 

570 

1450 

1542 

749 

661 

656 

 

Signals after reconnecting modem back inside after outside test:

DownstreamBonding Channel Value
Channel ID17 18 19 20 21 22 23 24 
Frequency555 Hz 561 Hz 567 Hz 573 Hz 579 Hz 585 Hz 591 Hz 597 Hz 
Signal to Noise Ratio38 dB 39 dB 39 dB 39 dB 38 dB 38 dB 38 dB 39 dB 
Downstream ModulationQAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 QAM256 
Power Level0 dBmV  0 dBmV  0 dBmV  0 dBmV  0 dBmV  0 dBmV  0 dBmV  0 dBmV  

 

UpstreamBonding Channel Value
Channel ID
Frequency370Hz 242 Hz 306 Hz 194 Hz 
Ranging Service ID1397 1397 1397 1397 
Symbol Rate2.560 Msym/sec 5.120 Msym/sec 5.120 Msym/sec 2.560 Msym/sec 
Power Level42 dBmV 40 dBmV 41 dBmV 39 dBmV 
Upstream Modulation[3] QPSK
[3] 16QAM
 
[3] QPSK
[1] 16QAM
[2] 64QAM
 
[3] QPSK
[1] 16QAM
[2] 64QAM
 
[3] QPSK
[2] 16QAM
 
Ranging StatusSuc Suc Suc Suc 

 

Signal Stats (Codewords)Bonding Channel Value
Channel ID17 18 19 20 21 22 23 24 
Total Unerrored Codewords146160432 145144737 145152925 145161110 145135709 145139803 145170015 145142227 
Total Correctable Codewords112 232 147 165 
Total Uncorrectable Codewords557 519 514 506 1762 2298 1499 1498
34 REPLIES 34
Spectrum Employee

Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

I'm disappointed to hear about what happened with chat support in # 4. Please, if you can spare a moment , PM any of the forum moderators with your account # and zipcode and they can get the feedback to the appropriate supervisor, or the person who manages the contractor group.

 

from what I can tell, your with and without the splitter is a "balanced 3-way splitter", as evidenced by the approx 5.5 dBmV loss in signal strength when passing through it (good guess?)  Frankly though, 5 to 6 dBmV is not actually better than 0 to 1 dBmV, as the "perfect" balance point would be exactly 0 dBmV which is referencing 1 mV exactly.  But while math is exact, real-world engineering is always "close enough" or "within acceptable tolerances".

 

To know more about this issue, kind of would need the error log.  Just because signal power levels are fine, doesn't mean there aren't other issues (ingress, egress, backfeed, etc etc etc...).  I'll try to check back on this topic tomorrow (not when on the clock of course)

 

My postings on this site are my own, off-the-clock, and don’t necessarily represent TWC’s/Charter's strategies or opinions.
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Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

Thanks for your help. Here is current log:

 

TimePriorityCodeMessage
Aug 25 2016 21:01:556-NoticeI401.0TLV-11 - unrecognized OID;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 21:01:555-WarningZ00.0MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:156-NoticeN/ACable Modem Reboot due to power reset ;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 20:42:236-NoticeI401.0TLV-11 - unrecognized OID;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 20:42:235-WarningZ00.0MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:156-NoticeN/ACable Modem Reboot due to power reset ;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 20:28:145-WarningT202.0Lost MDD Timeout;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 20:28:145-WarningN/ADS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 17:12:356-NoticeI401.0TLV-11 - unrecognized OID;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 17:12:355-WarningZ00.0MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:156-NoticeN/ACable Modem Reboot due to IP loss ;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 16:59:326-NoticeI401.0TLV-11 - unrecognized OID;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 25 2016 16:59:325-WarningZ00.0MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:156-NoticeN/ACable Modem Reboot from GUI/Configuration page ;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.0;
Aug 24 2016 20:55:565-WarningT202.0Lost MDD Timeout;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 24 2016 20:55:565-WarningN/ADS Partial Service Fallback: MDD Lost-> CM in DOCSIS 3.0 Recovery Mode ;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 24 2016 17:41:576-NoticeI401.0TLV-11 - unrecognized OID;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 24 2016 17:41:575-WarningZ00.0MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Jan 01 1970 00:00:156-NoticeN/ACable Modem Reboot due to power reset ;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;
Aug 24 2016 16:54:496-NoticeI401.0TLV-11 - unrecognized OID;CM-MAC=b0:77:ac:2c:aa:26;CMTS-MAC=00:17:10:8b:6b:12;CM-QOS=1.1;CM-VER=3.0;

 

 

Expert

Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

You are having some broadcast tv ingress from several local tv stations ch 40,42, 36,38,39. Probably a bad cable/connection out to the street if everything inside is good. . TWC needs to  come out repair that as well as install a proper grounding block bonded to your houses electric common ground point.

 It also looks like that splitter is bad if it's a 3.5 dB loss one as it has 5+ dB of loss . might be water in it or the line

 

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3de2cb6d1ccd8d99

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Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

@MsRayeThx it is a 3.5 DB splitter.  While researching I have read many of your responses in several threads with similar symptoms and i appreciate the help. The only other thing I could do on my end besides a new splitter would be to run new coax. I did buy 50 ft of quad shield but I didn't want to waste the money all in the cause of troubleshooting. Also, it is all the coax which TWC installed just a few years back. I will push to get a tech out here. Thx

Expert

Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

splitters go bad and using one as a grounding block even more suspect. If the line is overhead and run thru trees, the tree rodents have chewed it up and water gets in. Look at the center wire... is it still shiny copper or is it oxidised?

THe US seems to see the 3.5 dB loss but DS has 1.5 dB too much, are you sure the 75 ohm terminator is good?

 I'd also try the other cable temporarily,  see if it makes a difference.

 Main issue is too see if you get more DS partial service errors and skipped channels or high uncorrectables , especially on or next to local broadcast channels, you need to look at the TV fool report I linked and use a conversion table to convert the TV crf ch #'s to actual freq's in Mhz, like the table at WIKI

 

Browser

Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

cable is buried (goes under my driveway) and the pedestal is in my neighbors front yard . The terminator i used was brand new. No oxidation on any of the wires. The only reason i put the splitter in was to have it connected to what I thought was the home's grounding block. There are several other grounding wires there as well and i just reused the wire that was already there and most likely attached to the old cable drop (there are at least 3 drops to my house that I am aware of  - first two were bad resulting in the third).  

 

I will try the new cable and remove the splitter to just eliminate that from the equation. I have brand new 1 Ghz splicer to connect the new Quad RG6 to cable drop. Besides the obvious dangers of not having a ground (has been like that for years) , is it necessary to have it grounded for me to get to root cause on my issue? in other words, could this be my "last" test? 

Expert

Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

If that doesn't solve the problem, call TWC...  3 UG cable failures are unusual. and yes, there must be a grounding block correctly bonded per the NEC

 

Spectrum Employee

Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

It would appear you have ingress on the line, both the upstream and downstream are encountering intermittent packet loss.  The 19.4 MHz upstream in particular has a rather severe 0.2918% correcteds for the total and when I polled it just now it was reading currently at 12.3352% correcteds.

 

The facts support a strong suspicion that there's leak somewhere (in fact what MsRaye is mentioning about broadcast air wave signals shouldn't even come into play if the cable plant is properly shielded), and we thus need to find it.  If I'm right, it will be causing issues for you and your neighbors that one your street's run of your neighborhood's HFC node.  Cleaning up leaks is essential to cable plant health.  So. please call us and ask about setting up an appointment for "suspected ingress leakage, intermittent services out issue" for a proper investigation, scheduling when available that will work with your schedule.  Basically, it isn't a dBmV signal power level issue, it's probably a leak.

 

If you don't mind updating the topic later on what was the cause, I'm sure we'd would be interested to know (or at least I'm always interested in knowing).  One such case I had just today was from one of those cheap RadioShack white coax cables with the cheap gold fittings that was being pulled apart because the customer had decided the coax line would be good to use as a clothes hanger.  And another was caused by a lazy/inept installer who for reasons I can't fathom seems to have jammed/smashed an RG-59 fitting onto RJ-6 coaxial wiring, and left the metal braids sticking out the back (basically acting like a dipole antenna).  Moral of the story is there's lots of things that can cause a leak, but it always needs to get fixed ASAP as it affects both you and your neighbors on your street.

 


@MsRaye wrote:

If that doesn't solve the problem, call TWC...  3 UG cable failures are unusual. and yes, there must be a grounding block correctly bonded per the NEC



I've seen more unusual stuff. Smiley Wink Such as today when I got stung by 53.2 V (not mV, full-sized AC volts) from a brand-new home that contractor group that did the electrical wiring decided it would be a grand idea to use hammer-in staples and smash the coax wiring underneath that AC power wiring, clipping through the power wiring's ground in some places too because they put the staples on at an angle in some parts instead of perpendicular.  They basically have a possible fire-hazard in their home, made worse by the fact the customer use oxygen for medical stuff.  The world of electronics troubleshooting is full of suprises, I tell you...

 

My postings on this site are my own, off-the-clock, and don’t necessarily represent TWC’s/Charter's strategies or opinions.
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Re: Constant intermittent DS Partial Service Fallback: MDD Lost errors

Thanks for the follow-up. I really appreciate you digging back into this. I will call and get someone out.

Tonight I did replace the cable going to the modem with a new 50 ft RG6 Quad shield. I took out the splitter due to the comment on it losing more than the 3.5 is was supposed to and put 1 GHz splicer in its place. . So it is currently not grounded, but I wanted to ensure everything was new from the modem to the cable drop outside the house. The tech can address the lack of ground.

 

Thanks for everyone's time and input. I will come back with an update after the tech visit. Here is my current signal page after a reboot. 

 

DownstreamBonding Channel Value
Channel ID17 18 19 21 22 23 24 25 
Frequency555000000 Hz 561000000 Hz 567000000 Hz 579000000 Hz 585000000 Hz 591000000 Hz 597000000 Hz 603000000 Hz 
Signal to Noise Ratio38 dB 38 dB 39 dB 39 dB 39 dB 39 dB 39 dB 40 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
2 dBmV  3 dBmV  3 dBmV  3 dBmV  2 dBmV  3 dBmV  3 dBmV  3 dBmV  

 

UpstreamBonding Channel Value
Channel ID
Frequency37000000 Hz 24200000 Hz 30600000 Hz 19400000 Hz 
Ranging Service ID6380 6380 6380 6380 
Symbol Rate2.560 Msym/sec 5.120 Msym/sec 5.120 Msym/sec 2.560 Msym/sec 
Power Level39 dBmV 36 dBmV 37 dBmV 36 dBmV 
Upstream Modulation[3] QPSK
[3] 16QAM
 
[3] QPSK
[1] 16QAM
[2] 64QAM
 
[3] QPSK
[1] 16QAM
[2] 64QAM
 
[3] QPSK
[2] 16QAM
 
Ranging StatusSuccess Success Success Success 

 

Signal Stats (Codewords)Bonding Channel Value
Channel ID17 18 19 21 22 23 24 25 
Total Unerrored Codewords28304056 27288549 27297634 24612583 24582002 24585834 24586859 24617530 
Total Correctable Codewords32 78 14 16 27 30 58 38 
Total Uncorrectable Codewords731 2278 1431 2888 3027 1253 2264 2145