U

Visitor

 • 

21 Messages

Thursday, October 14th, 2021 3:37 PM

Closed

Modem Randomly goes offline for a few minutes.

Hi, I have been having some issues with my modem. I have talked to comcast tech support twice. They did something they called provisioning  and asked me if I was connected and called it a day.. but the issue isn't like that. My modem will go offline, comcast cannot see it when it is like this and then a few minutes later it's back. This happens at least once a day. I thought my modem was going out, so I bought a new one. Same thing happens. I've gone through all troubleshooting and nothing seems to fix it. I have tried every cable input in the house and I even replaced one of the coax cables. Tried multiple splitters. Currently it's a 2-way splitter supplied by comcast, only one cable going out and it's hooked up to the modem. Same thing happens every time. I don't really want to deal with a tech visit right now because of covid. Is there anything else I can try or is that pretty much my only option?

Expert

 • 

107.2K Messages

3 years ago

What do the modem's signal stats look like ? Try getting them here; http://192.168.100.1 or here http://10.0.0.1 


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

What is the exact make and model number of the modem ?

(edited)

Visitor

 • 

21 Messages

@EG The model of the new modem that is currently hooked up is Motorola MB7420. 

Downstream Bonded Channels  
  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
1 Locked QAM256 1 483.0 0.0 39.5 0 0
2 Locked QAM256 2 489.0 -0.7 39.0 27 0
3 Locked QAM256 5 507.0 6.6 38.9 966 2049
4 Locked QAM256 7 519.0 3.1 39.6 198 66
5 Locked QAM256 8 525.0 -2.1 37.4 32 0
6 Locked QAM256 9 531.0 -4.6 35.4 31 0
7 Locked QAM256 10 537.0 -5.8 34.5 6 27
8 Locked QAM256 11 543.0 -5.8 34.5 31 0
9 Locked QAM256 12 549.0 -4.5 35.4 32 0
10 Locked QAM256 13 555.0 -2.2 37.0 31 0
11 Locked QAM256 14 561.0 1.8 39.6 32 0
12 Locked QAM256 15 567.0 5.8 41.5 71 43
13 Locked QAM256 16 573.0 4.3 40.3 37 42
14 Locked QAM256 17 579.0 0.8 39.2 32 0
15 Locked QAM256 18 585.0 -1.4 37.7 36 0
16 Locked QAM256 21 603.0 -3.1 36.5 11 27
Total             1573 2254

 Upstream Bonded Channels  
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
1 Locked ATDMA 2 5120 29.2 49.5
2 Locked ATDMA 1 5120 35.6 49.8
3 Locked ATDMA 3 5120 22.8 49.3
4 Locked ATDMA 4 5120 16.4 49.0

These numbers seem to fluctuate, but this is what they are after rebooting my modem after going offline about an hour or so ago.

(edited)

Problem Solver

 • 

948 Messages

3 years ago

So, why even use a splitter if only one connection comes off it to your modem? I have had splitters do odd things, I personally would take that variable out of the equation….

Visitor

 • 

21 Messages

@jlavaseur the main line isn't running directly into the house. It's outside. The splitter is there for the 2 lines coming into the house. Would a coax cable connector be a better choice?

(edited)

Problem Solver

 • 

948 Messages

I guess I didn’t understand, I thought you said you had only one connection coming off the splitter, sorry my mistake

Visitor

 • 

21 Messages

@jlavaseur I went back and read over it, my post wasn't quite as clear. Sorry about that!

Expert

 • 

107.2K Messages

3 years ago

@user_e8f6cd 

The upstream power is high and it may be intermittently fluctuating even higher to out of spec levels. And some of the downstream channels are borked (SNR's are too low). And there is some cable *tilt* / *slope* going on. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.

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.


Good luck with it !

Visitor

 • 

21 Messages

@EG Thanks, I appreciate the help! I've replaced the splitter with a coax cable connector and I'm going to watch it over the weekend. Went ahead and set up a tech visit for next week just in case.

Expert

 • 

107.2K Messages

Quite welcome ! Please post back with how things turn out.

I am not a Comcast Employee.
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? Please mark an Accepted Answer!tick

Expert

 • 

107.2K Messages

3 years ago

@user_e8f6cd wrote: "Would a coax cable connector be a better choice?

If you are only using one of the indoor lines / outlets, then yes it would be a better choice. If both are being, used then you need the splitter.

Visitor

 • 

21 Messages

3 years ago

It's been about 17 hours since I removed the splitter and added the cable connector. There haven't been any disconnects so far, and my upload speeds more than doubled. However, my Downstream power levels are widely varying from -1.9 to 7.8 dBmV. I'm thinking that the real issue is definitely in the line coming from the pole to my house. I noticed this morning it looks like it's hanging loose in a section. Keeping my tech appointment just to have them check it out.

Expert

 • 

107.2K Messages

3 years ago

O/k. 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 !

(edited)

Visitor

 • 

21 Messages

3 years ago

Tech came out this morning, the line coming to my house was loose. They tightened it up at the pole and gave me a number to call if I continue to have problems, but they said what I was experiencing could definitely be causing the intermittent loss of connection.

Official Employee

 • 

3.8K Messages

@user_e8f6cd, thanks for getting back to us and providing this update! I am very happy to hear the tech was able to narrow down what could be causing the intermittent connectivity. We definitely want to ensure that was the problem and that the issue is no longer present on your end. Would you like us to follow up with you in a couple of days, or would you prefer to just reach back out at your convenience if you run into any further issues?  

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

Expert

 • 

107.2K Messages

@user_e8f6cd

Hope things hold up for you ! Good luck ! 

I am not a Comcast Employee.
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? Please mark an Accepted Answer!tick

Visitor

 • 

21 Messages

@XfinityAmira I can reach back out if there are any more issues, but so far things are going well. Thanks!

forum icon

New to the Community?

Start Here