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Contributor
Posts: 6
Registered: ‎08-25-2007
Accepted Solution

SB6141 Modem issue

Hello experts,

 

I installed a new Motorola SB6141 that replaced a Arris TM602G/CT, called support to provide the Mac ID to provision the modem, and then tested my connection.  With the Arris I never had issues with the connection issues and using speedtest.net always achieved ~33 Mbps downloads and ~6.5 Mbps uploads.  With the Motorola I go from not being able to open web pages, to when I can actually open speedtest.net achieving downloads anywhere from 1 Mbps to 25 Mbps.  

 

I just don't know if I am fighting a defective modem or configuration issue.  Does a bad modem behave like this?  Could it be a provisioning issues?  Any suggestions or help would be great as I don't want to return it paying a restocking fee if the modem is not the issue.

 

I can post the signal numbers if that would help

 

TerryJ

Connection Expert
EG
Posts: 43,801
Registered: ‎12-24-2003

Re: SB6141 Modem issue

[ Edited ]

road707 wrote:

 

I just don't know if I am fighting a defective modem or configuration issue.  Does a bad modem behave like this?  Could it be a provisioning issues?  

 

It could be either.

 

I can post the signal numbers if that would help

 

Can't hurt to have a look.

 


 

Contributor
Posts: 6
Registered: ‎08-25-2007

Re: SB6141 Modem issue

[ Edited ]

Thanks for the reply!

 

Here are the numbers:

 

My speedtest at the time of the post are 12.90 Mbps and 4.35 Mbps.  Still much lower than the Arris.

 

192.168.100.1cmSignal.png

Official Employee
ComcastMattV
Posts: 102
Registered: ‎10-10-2012

Re: SB6141 Modem issue

What speeds were you getting with your arris modem? Also you can private message me and I can check the bootfile for you as well.

Thank you

Comcastmattv
Connection Expert
EG
Posts: 43,801
Registered: ‎12-24-2003

Re: SB6141 Modem issue

The bootfile may be incorrect but also, the upstream power is high as is the downstream power. They are out of balance with respect to each other. This is not usual and my standard advice about excessive splitters can not be given in your particular case. It may be best to have a tech out to properly balance your line.

Contributor
Posts: 6
Registered: ‎08-25-2007

Re: SB6141 Modem issue

 

Thanks EG,

 

I checked again this last night and this morning as I noticed that the upstream power values are lower.  Not sure why.  ComcastMattV is going to look into the bootfile but with these new numbers does it sound like I should have a tech come out?  I have to look to confirm but I believe I have two splitters between where the line comes into the house and the cable modem.

 

Thanks again for the reply

 

192.168.100.1cmSignal.png

Connection Expert
EG
Posts: 43,801
Registered: ‎12-24-2003

Re: SB6141 Modem issue

45-46 dB is now good but the power levels shouldn't make greater than a 3-4 dB daily fluctuation. Perhaps there was some sort of a transient upstream / return path impairment somewhere yesterday.

Regular Contributor
Posts: 34
Registered: ‎11-17-2003

Re: SB6141 Modem issue

[ Edited ]

I have a similar issue with my brand new SB6141.  I had it provisioned, it lights up "green" according to CSRs on the phone and live chat, but my speeds are low and TCP connections time out after an initial burst of traffic.  When I switch back to my DPC3008 or an older SB6120 everything is fine.  Signal levels are reported consistently with each modem...roughly 36dB downstream SNR and 2-3dBmV power.  Upstream power is in the upper 30s.

 

At first the modem would not download a bootfile or the latest firmware at all.  It would stay with the factory fresh 1.0.6.3 firmware from August 2011 and also report two errors about downloading SW configs.  Later on, it eventually did update to 1.0.6.8, but my speeds are still slow.

 

Like the original poster, I can only assume the modem is defective, but I want to make sure it's not a configuration issue first.  The DPC3008 and SB6120 both hits 62/11mbps on speedtest.comcast.net with Extreme 50.  Could it be the fact that I have 3 modems still listed on my account equipment page causing a problem?  I can readily switch between both old modems and have connectivity.  With the SB6141 connected, speed tests just hang before getting to the download portion, but it does report a nice low ping.  Web pages of any sort load partially and very slowly.  The modem diagnostic/status page is accessible and everything looks good there...

Regular Visitor
splunk88
Posts: 3
Registered: ‎12-09-2012

Re: SB6141 Modem issue

[ Edited ]

I had the exact same problem with a new SB6141 I tried installing this week as the other two posters described.

 

Installed a brand new SB6141 I purchased to replace a leased WBM760A, then called Comcast to get it registered. Upon completion of set-up I could barely load pages. When various speed tests did not simply time out I would get download between .8 - 3 Mbps, upload speeds ~6 Mbps (!) and latency ~35ms.

 

After going through reboots and cache flushes with the phone tech that did not help, she scheduled a truck to roll which came the next afternoon (yay Comcast!). The tech checked out the set-up and finally declared the modem as bad so he hooked up the old Arris WBM760A and in a minute I was back to speeds of 36Mbps down and 6Mbps up.

 

I would still like to purchase my own modem to save the $7 monthly rental fee but I'm leary that another modem may do the same thing, especially the same model. I'm considering trying a Zoom 5314J but I still wonder it the problem was Comcast's provisioning as opposed to a bad modem. I'm interested to hear the other posters outcomes.

 

Thanks!

 

 

Regular Contributor
Posts: 34
Registered: ‎11-17-2003

Re: SB6141 Modem issue

[ Edited ]

I haven't really had anything bad to say about the Cisco DPC3008 so far.  It's an 8x4 modem based on the same Broadcom chipset in the Zoom 5341J.  The only minor complaints I have is 1) it's a little bit wobblier when standing vertically than the Motorola modems and 2) the status page does't have a reboot option or logs.  The Zoom 5341J is even less stable when vertical, and it comes with a fairly useless optional 'stand.'

 

I did notice my downstream power is higher on the DPC3008 than the Motorola hardware, but everyone says modem hardware isn't necessarily calibrated.  As long as it works...

Connection Expert
EG
Posts: 43,801
Registered: ‎12-24-2003

Re: SB6141 Modem issue

[ Edited ]

Anon286186 wrote:

 

the status page does't have a reboot option or logs.

 


Yes it does have a error log page. I have found that you have to log in two times consecutively, then the tab to it gets displayed. Also, look under the "Security" tab for the reboot option.

Regular Contributor
Posts: 34
Registered: ‎11-17-2003

Re: SB6141 Modem issue


EG wrote:
Yes it does have a error log page. I have found that you have to log in two times consecutively, then the tab to it gets displayed. Also, look under the "Security" tab for the reboot option.

Must be disabled with the firmware version I'm on.  There's no tabs at all after logging in with null user/password.

Connection Expert
EG
Posts: 43,801
Registered: ‎12-24-2003

Re: SB6141 Modem issue

What's the version number ?

Regular Contributor
Posts: 34
Registered: ‎11-17-2003

Re: SB6141 Modem issue

[ Edited ]

EG wrote:

What's the version number ?


d3000-v302r125532-120517a-L2VPN-CMCST.bin

 

Is it because I have the DPC3008-CC "Comcast Certified" version?  

Contributor
Posts: 6
Registered: ‎08-25-2007

Re: SB6141 Modem issue


Anon286186 wrote:

With the SB6141 connected, speed tests just hang before getting to the download portion, but it does report a nice low ping.  Web pages of any sort load partially and very slowly.  The modem diagnostic/status page is accessible and everything looks good there...


This is exactly how my SB6141 behaves when connected .  I had to go back to the Arris because I needed a working internet over the weekend.  Once I get a chance to work with ComcastMattV with the modem attached I will post the results.  With this many people having the same issue I am starting to believe it is a configuration issue not this many defective modems.

Connection Expert
EG
Posts: 43,801
Registered: ‎12-24-2003

Re: SB6141 Modem issue

[ Edited ]

Anon286186 wrote:

EG wrote:

What's the version number ?


d3000-v302r125532-120517a-L2VPN-CMCST.bin

 

Is it because I have the DPC3008-CC "Comcast Certified" version?  


Disregard. Sorry for the misunderstanding. I thought that you were referring to the Zoom 5341J not having an error log page. It is indeed known that the DPC 3008 had this disabled in the firmware.

Regular Visitor
splunk88
Posts: 3
Registered: ‎12-09-2012

Re: SB6141 Modem issue

Wondering how the two OPs problems with their SB6141s were resolved? Did you ever get the 6141s working, or did you try another brand?

 

An update... after returning the SB6141 I purchased that wouldn't work, I tried a new Zoom 5314J. Got it up and running with no problems. I'd recommend this modem to anyone wanting to own their own.

 

Fortunately I was able to get a refund on the 6141. Hopefully Comcast won't nick me for the truck roll.

 

Contributor
Posts: 6
Registered: ‎08-25-2007

Re: SB6141 Modem issue


splunk88 wrote:

Wondering how the two OPs problems with their SB6141s were resolved? Did you ever get the 6141s working, or did you try another brand?

 

An update... after returning the SB6141 I purchased that wouldn't work, I tried a new Zoom 5314J. Got it up and running with no problems. I'd recommend this modem to anyone wanting to own their own.

 

Fortunately I was able to get a refund on the 6141. Hopefully Comcast won't nick me for the truck roll.

 


I returned the SB6141 as I could not achieve acceptable results with it.  It was verified that I had the correct bootfile but the best I could get is less than 1Mbps download.  Strangely both the ping and upload speeds were as good or better than my existing Arris modem.  I will try a different model/brand but have not decided which one yet.  

Bronze Problem Solver
Jim721
Posts: 2,960
Registered: ‎12-05-2010

Re: SB6141 Modem issue

Zoom 5341J cant really go wrong. :smileycool:

Regular Contributor
Posts: 34
Registered: ‎11-17-2003

Re: SB6141 Modem issue

[ Edited ]

Yep, my DPC3008 works great.  It's just that I was used to having the Motorola status page, logs and the restart button.  The DPC3008 doesn't have logs with the Comcast firmware, and it only has a restart button from the web interface when it is in the process of ranging through the channels. 

Regular Visitor
splunk88
Posts: 3
Registered: ‎12-09-2012

Re: SB6141 Modem issue

[ Edited ]


I returned the SB6141 as I could not achieve acceptable results with it.  It was verified that I had the correct bootfile but the best I could get is less than 1Mbps download.  Strangely both the ping and upload speeds were as good or better than my existing Arris modem.  I will try a different model/brand but have not decided which one yet.  

 

 

Same here. While using the 6141, loading pages was so slow I'd get timed out, upload speeds were 6Mbps and latency normal. Sounds like either Motorola made a batch of bad modems, or Comcast has problems with provisioning 6141s correctly. Hmmmm...

 

Let us know what modem you end up getting next road707, and your results installing it. Again, the 5314J is one I could recommend from experience. Another modem I would have liked to have got is the Arris CM820A, but the sources were either shady or too expensive.

 

 

Contributor
Posts: 6
Registered: ‎08-25-2007

Re: SB6141 Modem issue


splunk88 wrote:


I returned the SB6141 as I could not achieve acceptable results with it.  It was verified that I had the correct bootfile but the best I could get is less than 1Mbps download.  Strangely both the ping and upload speeds were as good or better than my existing Arris modem.  I will try a different model/brand but have not decided which one yet.  

 

 

Same here. While using the 6141, loading pages was so slow I'd get timed out, upload speeds were 6Mbps and latency normal. Sounds like either Motorola made a batch of bad modems, or Comcast has problems with provisioning 6141s correctly. Hmmmm...

 

Let us know what modem you end up getting next road707, and your results installing it. Again, the 5314J is one I could recommend from experience. Another modem I would have liked to have got is the Arris CM820A, but the sources were either shady or too expensive.

 

 


I ended up with the 5341J and after 15 minutes with comcast it was up and running.  The numbers look good.  They are not any faster than what I had before but it will be nice to end the rental fee.

New Visitor
givemeliberte
Posts: 7
Registered: ‎01-05-2013

Re: SB6141 Modem issue

I'm running into the same issue and what I've found is that the modem needs to be manually provisioned using the SB6121 bootfile and most people in tech support aren't able to do this.  There's a thread on it here: 

 

http://forums.comcast.com/t5/Basic-Internet-Connectivity-And/Any-idea-when-the-Motorola-SB6141-will-...

 

 

If you get the right folks on the line you should be able to get it up and running but might take some doing.

 

Cheers and good luck.

Connection Expert
EG
Posts: 43,801
Registered: ‎12-24-2003

Re: SB6141 Modem issue

Solved thread closed.