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Modem keeps resetting itself

Frequent Visitor

Modem keeps resetting itself

Hello,

 

I was wondering if anyone on these forums has had a problem similar to mine. I use a Comcast-provided Motorola SB5101 SURFboard Cable Modem which in turn has a Linkysy E1000 router running off of it. Connected to the router are two devices; (1) my wired desktop computer and (2) my Xbox 360.

 

About two months ago, I started getting randomly disconnected. My modem would lose its ONLINE green light, then the SEND light, then the RECEIVE, and then finally the POWER light would go and the modem would reset itself. I bought the new E1000 wondering if it my old router might be the problem (it was fairly old). However, the problem still persists.

 

The main issue is that these disconnections are seemingly random. Some days it will not happen at all, sometimes it resets itself around every 2 hours or so, and sometimes (today namely) it resets itself almost every 20 minutes.

 

I have asked Comcast and they scheduled to send a technician out to my apartment, but the date came and passed and noone came.

 

Has anyone ever had this problem or a similar predicament?


Accepted Solutions
New Poster

Re: Modem keeps resetting itself

Thanks, Nerdburg.  I had realized that issue after my first post and had changed it consistent with what you are saying when I reorganized my lines with the 2-way splitter.  

 

A quick update: After I reorganized the lines, I got someone to write me a simple code to screen scrape from my modem status page every 45 seconds.  It scraped the upstream power which is where I suspected the problem to be and so, the program repeatedly stored that information in a computer for a 45-50 hour period.   It recorded huge swings in the upstream power: 47-54, particularly in the late evenings (sometimes one minute to the next). I would recommend anybody facing similar problem to scrape the content also.  This information proved to be quite useful when the tech guy came in.  As soon as he walked in, he measured the upstream power to be 49.3 and it looked okay to him.  When I showed him the swings, he started to methodically test for this issue related to this problem -- until then, I did not even know that such huge swings should not occur.  He thought that connection  somewhere might have got lose and he tightened everything outside my house.  He also replaced my radioshack modem.  Now, these appear to have done the trick. Keeping my fingers crossed!


All Replies
New Poster

Re: Modem keeps resetting itself

I'm having the exact same problem. It's been itermittent for the past several weeks, but has become extremely problematic within the last 10 days or so. Today it's been awful. Rebooting, resetting, ipconfig...nothing seems to help. I suspect it's Comcast's connection somehow, not the actual modem.

Gold Problem Solver

Re: Modem keeps resetting itself

Definitely not my area, but did you both read the 'sticky thread' at the top off the Forum page?

 

 

http://forums.comcast.com/t5/Connectivity-and-Modem-Help/Information-Required-for-Connection-related...



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Regular Visitor

Re: Modem keeps resetting itself

 This has been happening to me for the past 6 months. Exact same issues as you. The technicians have been out -several- times and they are still unable to figure out why it is still doing this. Changing the modem does nothing nor the cables or splitters. They've tested the modem and everything checks fine and within optimal ranges. I've given them the logs of when this happens and they said they would keep track of it but nothing has come from it. Main problem is that it works fine when they are here so they can't see what's happening within the 15 secs it's resetting.

 

I'm stuck with sub-optimal service and as soon as another provider shows up to my area, I am droppping Comcast immediately.

Frequent Visitor

Re: Modem keeps resetting itself

I'm with you on that one; chalk up a new record, my modem has reset 7 times already today.

Expert

Re: Modem keeps resetting itself


AllAboutSpeed wrote:

I'm with you on that one; chalk up a new record, my modem has reset 7 times already today.


You have yet to post the requested data from the link that CCCarole replied to you with..

Expert

Re: Modem keeps resetting itself

Please give us more information:

1) Please connect your computer directly to the modem via Ethernet ( no router, no wireless, no USB )
2) Run ShaperProbe and post your results.
3) Post your upstream and downstream signal levels (click the link.) We are interested in your power levels (dBmV) and your Signal to Noise Ratio (SNR).
4) Let us know to what speed tier you subscribe.
5) Post the make a model of your modem.
6) Please let us know to what speed tier you subscribe.

New Poster

Re: Modem keeps resetting itself

Hi Nerdburg,

 

I have similar issues as well.  I am using a Motorla Surfboard 5101.  I am in the Economy tier.

 

========================
DiffProbe beta release. October 2009. Build 1002.Shaper Detection Module.

 

Connected to server 64.9.225.166.

 

Estimating capacity:Upstream: 4217 Kbps.Downstream: 20601 Kbps.
The measurement will take upto 2.5 minutes. Please wait.

 

Checking for traffic shapers:
Upstream: Burst size: 4763-4840 KB;Shaping rate: 2128 Kbps.

Downstream: Burst size: 9938-10316 KB;Shaping rate: 12786 Kbps.

 

For more information, visit: http://www.cc.gatech.edu/~partha/diffprobe
==========================

Downstream:

 

Frequency 573000000 Hz

Signal To Noise Ratio 37.1 dB

Power Level13.6 dBmV

Channel ID 12

Frequency 23600000 Hz

Power 49.4 dBmV
==========================

 

I have been on the phone with comcast reps for many many hours now but have not got to the bottom of the problem.  One seemingly knowledgable rep mentioned that he saw in the log maintained at comcast the ip address (or something else which I don't quite correctly recall) for my modem gets renewed often.  He and other reps have given me different reasons for why my modem resets and I am not completely sure I agree:

1.  Modem is Docsis 2.0 whereas comcast apparently recently upgraded to 3.0 in our area: I would have suspected the upgrades to be backward compatible. The rep suggested that I get docsis 3.0 modem to resolve the problem.  

2. Device problem: I earlier had an Arris cable modem (docsis 1.0 device) connected and it encountered similar issues.  I have tried different routers (Linksys versus Apple) as well but even then the problems continue.

3. Splitter problem: I have the line from comcast going to an amplifier, split into three: one of which goes to the cable-modem and the other to two different TVs.  Since I have had no problem with the TVs, I interchanged outputs -- the cable-modem now connects to the output which was earlier feeding the TV.  Even then, the problem continues.

 

I am left to wits end and would appreciate any help.

 

Thanks in advance

 

Frequent Visitor

Re: Modem keeps resetting itself

@ I-am-a-cc-user

 

I got Comcast to replace my 5101 with a Cisco 2100. I have had no problems since.

New Poster

Re: Modem keeps resetting itself

Thanks, Allaboutspeed.  Cisco 2100 is also a DOCSIS 2.0 modem.  I suspect I have a problem on my line or devices outside my house.  I saw my upstream power requirement to swing up to 54 dBmV more than once.  Since then, I have reorganized my line coming in.  Now, outside line > 2 way splitter (a gold plated one I got from Radioshack yesterday) >one output to cable modem > another output to the TVs.  I thought I had a slight improvement - the Internet did not drop during the daytime.  But, it started dropping in late evening.  Again, the upstream power was in the 54 dBmV range.

Expert

Re: Modem keeps resetting itself


i-am-a-cc-user wrote:

 2 way splitter (a gold plated one I got from Radioshack yesterday) >


 You'll want to replace that with something else. (Like this: http://www.techtoolsupply.com/ProductDetails.asp?ProductCode=GHS-2FC)

Expert

Re: Modem keeps resetting itself


i-am-a-cc-user wrote:

3. Splitter problem: I have the line from comcast going to an amplifier



You'll want to get the modem off the amp. Ideally you want a 2-way splitter off the main line. One leg should feed the modem while the other feeds everything else.

New Poster

Re: Modem keeps resetting itself

Thanks, Nerdburg.  I had realized that issue after my first post and had changed it consistent with what you are saying when I reorganized my lines with the 2-way splitter.  

 

A quick update: After I reorganized the lines, I got someone to write me a simple code to screen scrape from my modem status page every 45 seconds.  It scraped the upstream power which is where I suspected the problem to be and so, the program repeatedly stored that information in a computer for a 45-50 hour period.   It recorded huge swings in the upstream power: 47-54, particularly in the late evenings (sometimes one minute to the next). I would recommend anybody facing similar problem to scrape the content also.  This information proved to be quite useful when the tech guy came in.  As soon as he walked in, he measured the upstream power to be 49.3 and it looked okay to him.  When I showed him the swings, he started to methodically test for this issue related to this problem -- until then, I did not even know that such huge swings should not occur.  He thought that connection  somewhere might have got lose and he tightened everything outside my house.  He also replaced my radioshack modem.  Now, these appear to have done the trick. Keeping my fingers crossed!

Expert

Re: Modem keeps resetting itself

That's good news Smiley Happy

New Poster

Re: Modem keeps resetting itself

3 to 4 times a day i have to reboot my router(motorola sbg900 surf board--i own) not only do i loose internet acces but the modem for the phone also goes down, then i have no phone service. can someone look at the below information to see if there is a problem. or can anyone tell me what i need to do to prevent this from happening over and over again, very frustraing when you in the middle of trying to do something.

 

 

DiffProbe release. January 2012. Build 1008.
Shaper Detection Module.

Connected to server 80.239.168.233.

Estimating capacity:
Upstream: 4292 Kbps.
Downstream: 21137 Kbps.

The measurement will take upto 2.5 minutes. Please wait.

Checking for traffic shapers:

Upstream: Burst size: 4466-4546 KB;
Shaping rate: 2128 Kbps.

Downstream: Burst size: 7591-7878 KB;
Shaping rate: 15829 Kbps.

For more information, visit: http://www.cc.gatech.edu/~partha/diffprobe

New Poster

Re: Modem keeps resetting itself

still need help to prevent rebooting modem many time per day

 

2nd test, not sure if it is any different

New Poster

Re: Modem keeps resetting itself

DiffProbe release. January 2012. Build 1008.
Shaper Detection Module.

Connected to server 74.63.50.21.

Estimating capacity:
Upstream: 4390 Kbps.
Downstream: 20350 Kbps.

The measurement will take upto 2.5 minutes. Please wait.

Checking for traffic shapers:

Upstream: Burst size: 4722-4805 KB;
Shaping rate: 2128 Kbps.

Downstream: Measurement aborted due to high packet loss rate.

For more information, visit: http://www.cc.gatech.edu/~partha/diffprobe

New Poster

Re: Modem keeps resetting itself

I was having this exact same issue and the solution was very simple: the power cord for the modem was powering the router and vice versa. This is an issue because each device has different voltage and current needs. So, check to make sure that the right cord is going to each hardware. If they aren't labeled you can check that the voltage and current (amps) output are matched, which should be listed each each device and each power adapter

New Poster

Re: Modem keeps resetting itself

I believe the problem is in the wiring to the home from the outside. You should check if all outer cable are properly insulated and not damage. If so, time to replace the cabling.
Expert

Re: Modem keeps resetting itself

10 month old thread now locked, the OP has not returned.