Rookie

Intermittent Connection Loss

 I have a self-owned TP-Link TC-7610 (TWC approved) that I purchased in June and which had been working perfectly up to about a 11/17, when the internet connection dropped and the internet modem light would not come back on after several power resets. Called TWC and tech said things looked fine on their end, suggested may be problem with the modem, and offered to send a tech out. I figured I would try getting a new modem before paying for a repair visit. Left it for a few hours, and it came back up again.

 

I was good until last night, when the same thing happened. Left it alone till this morning. It came back, then dropped, then came back, then dropped. I made a few pdf printouts of the connection status and error log at various times, which can found at this link:  https://1drv.ms/f/s!Aqfe__XlRCN9gaEv4CTrtYxrUSwN2g

I went ahead and bought a different modem, but the connection is now back. If/When the drop happens again, I’ll try swapping out the modem, but I thought in the meantime I would post here to see if anyone could diagnose from the error log. Thank you.

12 REPLIES 12
Proven Sharer

Re: Intermittent Connection Loss

Your modem receive levels are too low.  That tells us you have too many splitters in the cable line.  Your data modem must be either connected direct to the street feed cable or on the first two-way splitter if you pay for both internet and other services from TWC.  Right now your modem is SHOUTING to be heard and may be causing problems to other users in your area.

Rookie

Re: Intermittent Connection Loss

Thank you for the response. I have since swapped in a new cable modem router (TP-Link TC-W7690). So far so good.

 

I live in an apartment (4-storey bldg built 2012). There are cable jacks in the living room and both bedrooms. I pay for internet only, but presumably previous tenant had multiple services. Since I don’t how the jacks are split, sounds like you’re saying if the new modem doesn’t work out, I should try the other rooms? What would be an acceptable receive level, and on what configuration tab would I find that info?

Proven Sharer

Re: Intermittent Connection Loss

The data you want to examine appears on your 4th pdf; I think it will be found on the tab labeled CONNECTION INFO.  When you look at that page you'll see a section labeled "Downstream Bonded Channels" and a large table just below.  In that table there is a column labeled "Power' with values in dBm.  The minimum desired receive power level is -8.0 dBmV, while your levels all showed -11 or lower.  Here more is better, to a point.  For the curious, the maximum desired power level is about +10 dBmV.

The lower part of the same page has a table for "Upstream Bonded Channels" which are used for uploading data, and a column labeled "Power", also in dBmV.   Normal numbers here are +30m  to +45 or so.  The maximum level applied to the cable should never exceed 51.0 dBmV; yours was running 58.0 earlier.  That's why I said your modem was SHOUTING -  it's sending a signal strong enough to cause signal distortion in TWC's equipment.  If one of your neighbors complains and TWC identifies your connection as the source they can (and usually will) disconnect you until your problem can be fixed.

 

So YES, you do need to call TWC for service, and don't let them tell you on the phone that "Everything looks good here" or "Your modem needs to be replaced."  Make copies of those pdfs for the service tech to view when he shows up. He can probably find the splitter serving your apartment fairly quickly.  He can then reconfigure the cables to bypass the extra splitters that were needed before.  My hunch is that will change both levels by about 7 dBmV in the desired direction (DS to around -4 and US to around +47. 

A good tech will check all the cable connectors to make sure they are properly attached and tightened.  He may also determine that holes in  the plastic jacket of the cable drop from the street have allowed some water in, causing extra signal loss in both directions.  That would require replacement of the drop line (not at your expense).

 

Expert

Re: Intermittent Connection Loss

Both levels are bad and NO MODEM WILL WORK PROPERLY, There are excessive splitters inline and since it's an apartment building, no surprise.Woman Mad

Whoever you talked to on the phone NEVER LOOKED AT THE LEVELS and simply wasted your time AND MONEY on a modem or two. Robot Mad

The single channel upstream at +58 indicates the modem has defaulted to "catastrophic" recovery mode, It's concentrated every last bit of upstream power onto one channel with tx partial service.

This is going to need a tech out to find out where the loss is and remove at least1 if not 2 splitters.

As for phone support.... Cat LOLMan LOLRobot LOLSmiley LOLWoman LOL ....

Any upstream over +50 dBmv or downstream below -8 dBmv should have given them a yellow flag and maybe they'll send a tech depending o what phase the moon is in and whether you have a pleasant voice.

 And at +58 up and -11 down red flag and no question as this needs a tech sent out. It CANNOT be fixed over the phone no matter what they claim, or try to cancell the call the day before the tech is scheduled because it "sorta works"

.

 If it looks anything  like the below photo, there is NO EXCUSE to not send out a tech as well as the bucket truck guys to put in enough tap off blocks for all suites rather than excessive splitters! there are also open splitter ports with NO terminating resistors further adding to the imballance .

http://i.imgur.com/iUeEzFD.jpg

iUeEzFD

 

Expert

Re: Intermittent Connection Loss

since I think you've got 1 or 2 extra modems, stick them on those other jacks and see if the lights change state after you connect the coax.  flashings bad, steady indicates somewhat of a lock on channels.

It's possible they will load the splitter properly and get the levels at the turned on modem in range.

You can look at the level page even if the modems not activated and  without a router it will be at 192.168.0.1 not 192.168.100.1

Rookie

Re: Intermittent Connection Loss

I almost mentioned that we have been having a huge amount of rain this year. I will definitely follow your advice and request a repair visit. Thanks!

Rookie

Re: Intermittent Connection Loss

Thank you, karlbeckman and MsRaye - you guys are the bomb! I love all this detail because it makes me feel well-armed and less helpless. Cheers!

Expert

Re: Intermittent Connection Loss

print out the level page you posted here and do another before the tech get's there, especially if the modem starts working again.

This is too many splitters in line and can very well be a littlecorrosion pushing it over the threshold of not working at all. It can also be due to issues in other apartments generating noise and upsetting the splitter/tapoff you're on.  someone may have moved in or out and there's empty ports in their suite, or some sort of electrical ground loop blew out a splitter.

 The modems single channel max tx level is +58 dBmv . If the CMTS needs more to make it thru the splitters and noise, The modem will start to run slow or start resetting to try to find good channels.

The photo I posted is of a building with around 30 suites wired to only two, 8 port tap off blocks when there should have been 4..

I'll bet there's a 4 way on the line from the street and then in each suite there's another 4 way resulting in 15 dB of loss.

 Hopefully TWC can find the splitter and eliminate it.  Is there a TWC box outside you can get a photo of?

 

Rookie

Re: Intermittent Connection Loss

So the TWC (now Spectrum) tech came out this a.m. He seemed very competent (in-house, not a contractor), and it looks like he's fixed my problem.

It seems for some unknown reason there were two lines into my unit. One was run to the jack I use for internet, and the other was split among the other unused jacks. He said if I wanted to use the other jacks I would need an amp installed, but I have no plans to do that (I use Chromecast to stream to my video projector to watch stuff).

My downstream power levels are now close to zero, and upstream power is about 49. 

Thanks again for the help!