Time Warner Cable - Legacy → SB6141 Bonding Channel question(s)

I am not an expert but I can give you my recent experience. I have spent the last 3 weeks with 2 techs out to my house, numerous calls to TWC, twitter chats with TWC_help and finally today my problem was solved.

The first tech barely checked anything in the house, went outside for a little bit and came back in and called in a low digital power problem. Supposedly TWC did some adjustments on the node and I did see an increase in my SNR from 29db to the 31-33 range (on 3 of my 8 channels...my good channels were all at 38db). However, I was still having the same issues as you. My speed would drop from 100mb to less than 3, then recover, sometimes after the modem rebooted itself. Occassionally instead of 8x4 bonding I would get 5x4 with all the bad channels gone and it would work perfect.

2 techs came out today and finally narrowed down my problem to a poorly crimped connector at the wall plate near my modem that was lazily installed by the builder when the house was built. They changed out the connector and boom I was getting 38 db SNR across all 8 channels.

Keep hounding them. I was actually contacting them so much and so often that a manager called me and gave me her direct line so that we could be in contact until this was resolved.

Looking at those receive signal levels, it looks as though there is a high pass filter in the line that starts rolling off below about 525 MHz. Could be a corroded center conductor at one of the connection points, or a bad splitter.

There's not many connections between house and modem. Two main lines into splitter/one line from outdoor box to wiring closet that has one coupling to modem. I'll go out and change the outdoor splitter to see if that helps. Just seems like it's more likely at their street junction, since nothing has changed or moved within the house.

Same problem last night, lost connection, rebooted, connected at .8mbps. Lost connection overnight, rebooted this AM and is now 22mbps. Same "bad" channel 3 appeared when running slow. Do they have a way of turning off channel 3 if I call them?

I would just call them to come out and check. They have a signal meter that measures ingress on the line. They hook it up and get a readout to narrow down the issue.

I have very few connections as well...main line comes in to panel in the closet, from there a barrel connector connects the main line to the line that runs thru the house to the wall plate where my modem is placed. Then a jumper to the modem. With the signal meter they were able to narrow down the problem between the modem and the closet. They took the wall plate off at the modem and switched out the connector and it solved the entire problem.

I am the only owner of this house since it was built 7 years ago. I have never taken that wall plate off or messed with that connection. Whoever did the initial installation during construction did a poor job with that connector and it just now started causing the issues.

My problem is, almost 2 days and things were "perfect". Today channel 3 pops back up and slows to .5mbps today. It is humid and wet out, but why would the extra channel 3 show up because of that? If I could block channel 3 all issues would go away. Modem page looks like picture #1 today, #2 past 2 days.

I'm guessing if I call them out, it will be dry out and have no issues, so they'll just say I'm nuts. All my connectors (2) from outdoor box to modem look good. Will call again today and try to get someone than knows about channels.

edit: Long chat with TWC. After 30 minutes of "diagnosing".... I got a case#. He had me hook PC to modem and disconnect my firewall for a bit... speedtest went from .5mbps to 22mbps with FW turned off. Back to .5 after turned back on. Then he had me run a Tracert to Google:

Tracing route to google.com [2607:f8b0:4000:801::1006]
over a maximum of 30 hops:

1 * * * Request timed out.
2 * 12 ms 11 ms 2605:6000:0:4::e:20c3
3 15 ms * 13 ms 2605:6000:0:4::3:280
4 17 ms 27 ms 20 ms 2605:6000:0:4::22
5 21 ms 19 ms 37 ms ae-4-0.cr0.dfw10.tbone.rr.com [2001:1998:0:8::6]
6 22 ms 14 ms 17 ms 2001:1998:0:4::1a3
7 29 ms 26 ms 14 ms 2610:18:12e:4040::3d
8 55 ms 47 ms *

He said something looked off and gave me a case#. Hooked my router back in and I'm back to 22mbps for now. Very strange. Will call the secret number when it slows down again...

Do you have TV service?

If not, then more then likely you have a filter on the line (likely at the tap) that is blocking/degrading channels below 525 mhz and it needs to be replaced or removed by a TWC tech.

The modem channels are picked by the CMTS as it balances load. Phone support can't change them. As signal levels change normally a few dB due to weather and temperature, that poorly working channel may not be able to connect at all, which actually seems to improve your connection at the cost of less bandwidth capacity.

Here's a very similar issue:
»Total (Un)correctable Codewords for one channel on SB6141 is high

That sounds most likely. I will call next time it's slow and get them to send someone out. No TV, just internet. Odd, I checked speed 10 minutes ago and it was .5, checked it 1 minute ago and it was 22, no reboots between. Definitely something not coming through reliably.

Well, I've had >22mbps for a day! One thing that "may" have been an issue that I changed:

1. Added OpenDNS servers to PC and router (from TWC)
2. My router had # IP addresses set at "50" 100-149. I have a device (Ooma) that I had set a static IP on as .150 Maybe a conflict?

If I slow in the next day or two I'll call again.... definitely paying to much for this crappy service! $67.22 for Turbo and that's with a $4.84 promo credit. Think I'll switch to Earthlink (same cable at much less$$)

I had a similar issue, had a 6141 that worked fine until the additional bonding channels were added, the signals looked like yours. In my case my modem was rebooting constantly. TW dispatched a tech and he replaced an old filter and replaced the cable drop from the outside and also the inside wring.

I haven't had an issue ever since, my suggestion for you is to request a technician to check your wiring and replaced the filter.

ditto to your situation... Austin, same modem.

channels bonded always less than 8. typically 5.
(3 digit numbers are mhz). 507 seems to never bond, 513 and 519 always error prone. (uncorrectable codewords are 3 orders of magnitude worse than 'good' channels). channel 525 is marginal, not as bad as 513 and 519 but high error rates compared to good channels. channels 531 and higher always good. errors occur even if power level is 33 db on problem channel.

performance is good most of of the time but goes really bad when any of the bad channels are bonded.

I do have a filter in my line, installed by twc. i suspect it is causing the problem. I have a tech coming next week but I may cancel as things are running good now and I don't want a tech visit without a problem to investigate.

Other symptoms included random modem restarts, initiated by modem itself, t4 timeout, plus a log full of "Lost MDD Timeouts", DS partial service fallback, and "MDD recovery following MDD Loss". Log entry rate varies also; poor performance yields more log entries.

my other modem, docsis 2, bonds at 531 and is rock solid. according to other sources when austin upgraded in June they added new QAM channels in the range of 500 to 540.

I have the exact same modem and had line issues as well. Your power levels are out of the "acceptable" range. My SB6141 had downstream power levels of -16dBmV to -11dBmV and I had high latency, odd speed ranges, packet loss, and intermittent disconnects. I also got dropped to one upstream channel. After the tech came I had 4 downstream and 4 upstream channels. Power levels went to 0dBmV across the board for downstream and upstream dropped from 58dBmV on a single channel to 4 channels at 44dBmV. What changed: 5Mhz - 2000Mhz splitters were used to replace older ones, both the business and residential connections directly came off of the first 3-way splitter with the largest gauge coaxial cables. The third line is what was used to run to another splitter for multiple TV's. The point: My bandwidth increased both up and down, latency went down, connection stopped dropping, packet loss stopped, speeds and latency are stable now. Call and have a tech come out immediately.

Will they come out even if there is no "immediate" issue? Lately it seems to lose connection each night, but when I reboot it normally comes back with normal speeds (and channel 3 not bonded).

One other question. In the outdoor box, there are 2 coax lines coming from the street into a combiner (splitter), into the one line going to the modem. I only have internet, are both lines necessary? The more hardware I can eliminate the better.

Yes they will come out as soon as possible if you explain the reason. They will be able to see that your connection is dropping and that the signals aren't technically that great. The closer to 0dBmV the better.

For the second question, it sounds like a diplexer is being used for whatever reason. I would disconnect the two lines and then test each one directly connected.

OK, I removed the splitter. At first channel 3 didn't show up and all was good, but now it is showing 27dB, -13dbmv. As soon as channel 3 showed up, speed dropped from 22 to 1.6. Splitter is/was 5-1000mhz. Will be getting them out here!

I had similar problems to you. I had 5 to 6 bonded channels, random modem reboots, random poor speeds, high error rates on certain downstream channels, etc.
So the new news:
I have a power surge protector with cable connectors on it. I had my cable routed through this strip on the way to the modem. I have no TV or phone service on cable and no splitters. I just bypassed the surge protector and now my signals look great with 8 channels bonded and all of the bad stuff above is gone. I had no idea the surge protector would have been the problem, but now I see it has been for others.

I had no issues when I went to 8/4 bonding in Austin several months ago, however my signals suddenly went bad about 3 weeks ago. At the time, I thought I could have the same filter issue others had mentioned and I was about to call Time Warner. However, I first checked the cable from the wall to the cable modem. I believe someone in the house had pushed my daughter's doll house too close to where the cable was coming out of the wall. I believe my signal issues were a direct result of the cable being forced into too sharp a turn. I'm not sure whether a sharp turn in the cable can cause such a signal degradation or whether it caused a problem with the connection in the outlet.

I pulled the doll house away a few inches and moved the cable a little and saw that my signals returned to normal. I had been getting billions of uncorrectable errors on two of the eight channels over a period of about a week. The modem had been rebooting pretty often with timeouts and slow download speeds. Since making this slight adjustment to the cable last week, everything is back to normal with only a few thousand correctable errors on each channel. I'm getting about 108 Mbit down and close to 11 Mbit up.

So it is definitely a splitter? If it is then you will see an improvement if you get a 5MHz - 2000MHz splitter (Which should have been used in the first place). I swapped the incoming splitter to a 5MHz - 2000MHz and used the largest gauge coaxial cable straight to the modem. My latency went down, the SB6141 stopped dropping, and I recieved more bonded channels. Also, my downstream power levels went from -15dBmV to 0dBmV across all channels and the upstream power level dropped from 58dBmV to 44dBmV. My connection is solid now. I haven't had any sort of hiccup since doing this. I would still request a technician to come over and then try to get a credit/discount for the months that you were having a lot of issues. I got credited for the month that my connection was clunky/dropping.

The issue is on their end then. You have a new house with new lines. You should have no problems getting credited for the poor service you have been paying for.

I just took it out and put a coupling. No improvement, so I put it back like it was for when they come out. It is a splitter, I was looking at it backward the first time. Two lines go into the house, but only one is used to the modem. One connected, the other did not. Worked for an hour then went back to slow.

Made appt., not coming out until next Tuesday, they must have a LOT of service calls. Should be able to keep it limping along until then.

Wow! Compare the Signal in first post to the one I just got after tech's left. They replaced an old filter at the street, and added a missing ground block. Hopefully things will be more reliable!

hi gang, i figured i'd revive an old thread rather than start a new.

now that i have 20/2 maxed to 100/100, take a look at my numbers
and let me know if anything seems not kosher to you;