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bterry89

@comcast.net

[Connectivity] motorola SB6121 can't keep a connection...

HI, I bought a new modem yesterday because I wanted to upgrade to a faster better one.(right now im using the one they gave me the SB5120.)when 3 or more people use the net it slows down tons or I could be the only one on and it just slows down particularly on my xbox, to unplayable speeds. Also I bought it to save money monthly since I have had the service for over a year already. any who I called comcast to activate it which they did, and everything works fine for about 5-10 minutes then it just drops and does the whole cycling to reestablish a connection and than it just drops and restarts again. this never stops until I pull the power supply and it goes through the same said process as before:(.

Also I thought it could be my router which is a ASUS R56U which has no problem connecting to my old modem. So I updated the Firmware and source code. but I came to the conclusion that it wasn't that when I tried to just directly connect the new modem to my computer same problem as mentioned above. well at least so far I got to update my router!

I really am looking for help before I go through the process of returning this puppy got it through amazon..



bterry89

@comcast.net

N56U*


ExoticFish

join:2008-08-31
Stuarts Draft, VA

What speed package are you on ? What are your signal levels ?
--
»www.VAJeeps.com
»www.BronzedBod.com



Streetlight

join:2005-11-07
Colorado Springs, CO
reply to bterry89

Provide the information requested in the link:

»Comcast High Speed Internet FAQ »How To Get Help!

in order to get help in this forum.

Also, before you replaced your older modem, did you have any problems?

It's possible that your modem has been provisioned with a slower level of service than what you had on the older modem and as your other home network begins using the net, things bog down. For many modems the configuration file name is listed in the modem's web pages at »192.168.100.1. However, some have reported problems getting that file name from Motorola modems after they've been up and working for a while. If you have the configuration file name, report it here along with the other data requested. There have been many reports in these forums of mis-provisioning of modems for lower speed than was paid for. Eventually, it can get corrected. Sometimes it takes a message to Comcast Steve at the Comcast Direct forum to correct things:

»Comcast Direct
--
There is nothing more deceptive than an obvious fact.

Sherlock Holmes in
The Boscombe Valley Mystery
A. C. Doyle
Strand Magazine, October 1891



PeeWee
Premium
join:2001-10-21
Madera, CA
reply to bterry89

Comcast support needs to reset it again on their end. This happened tome. Otherwise leave it alone and connected and let it go through a number of restarts and it should finally settle down. This is what Comcast told me. I insisted that it wouldn't stop and they found it to be on their end.
--
Iphone. Helping computer illiteracy become popular since 2007



bterry89

@comcast.net
reply to bterry89

sorry I live in Visalia, CA. I have the performance package and I have Blast! package and I was on the phone with comcast for a fourth time And I think it might actually be my new SB6121 router.. because it holds a connection fine if its not plugged into any router or direct connect. the moment that happens it completely shuts off and it will never reestablish connection again..
So that being said I know my post is a little unorthodox and I apologize. I did make an appointment for the tech to come by monday I think he will tell me it is my new modem and there is nothing he can do about it or am I wrong?



Cable_NOT

@comcast.net

said by bterry89 :

sorry I live in Visalia, CA. I have the performance package and I have Blast! package and I was on the phone with comcast for a fourth time And I think it might actually be my new SB6121 router.. because it holds a connection fine if its not plugged into any router or direct connect. the moment that happens it completely shuts off and it will never reestablish connection again..
So that being said I know my post is a little unorthodox and I apologize. I did make an appointment for the tech to come by monday I think he will tell me it is my new modem and there is nothing he can do about it or am I wrong?

Have you tried a different Ethernet cable for the SB6121 than you used with the SB5120? The SB6121 has a gigabit Ethernet interface, and that means that it looks at pins 4-5 and 7-8 in the Ethernet cable, but the older SB5120 would ignore those pins. If there were a short circuit on those wire pairs, or if there were a bad connection on one of those wires (which could enable the other wire in that pair to act as an antenna and pick up noise), that might cause problems for the SB6121 that the SB5120 would not experience. If you bought the "retail packaged" SB6121, you should have received a new Ethernet cable with the SB6121, and I would suggest that you try using that cable if you have not already done so. It won't take long, and it might save you the hassle (and extra delay) of exchanging your current SB6121.

andyross
Premium,MVM
join:2003-05-04
Schaumburg, IL
reply to bterry89

If the modem is constantly rebooting, then it may be a signal issue. We really need those numbers.

Also, in areas with upstream bonding, the 6120/6121/6141 have a known issue where one of the channels can 'timeout' and it locks it out. With the latest firmware, it shouldn't reboot. Also, with upstream bonding, the upstream signal levels are more critical. They need to stay in the 40's for it to work properly. Single channel can go into the mid-50's.


ExoticFish

join:2008-08-31
Stuarts Draft, VA
reply to bterry89

Which is it, Performance or Blast ?

And we need signal levels.
--
»www.VAJeeps.com
»www.BronzedBod.com



bterry89

@comcast.net
reply to bterry89

downloadScreen Shot ···.pxm.zip 82,793 bytes
there is what I pay for
thank you so much for the help and guidance!

I will be sending you the motorola modem stats asap!

but here is what comcast says I pay for I dunno if I'm getting screwed now or what. and I'm sorry I can't remember what mbps I pay for


bterry89

@comcast.net
reply to bterry89

Click for full size
Signal
Click for full size
Log
ok here is the signal and also the logs cause this happens every Time I plug in the SB6121. also I am using the ethernet cable the SB6121 came with.

Bterry89

join:2013-01-06


heres what I pay for
sorry I forgot to change it to jpg my.. noob mistake. ~.~ but I cannot recall what I get from having that maybe somewhere around 30-40 mbps.


Streetlight

join:2005-11-07
Colorado Springs, CO
reply to bterry89

Your downstream signals look fine, but the upstream power levels a high. Some folks will say they are within spec, but my experience (different modem) is that when upstream power gets to or above 51 dBmv, I would lose internet. The fix was for Comcast to replace the buried drop from the pedestal to the ground block on the side of the house as a tech found ingress from that damaged, 30 year old line. Different modem models may have different sensitivity to high upstream power levels. Modems are not always perfectly accurate in their measurements, so your actual power level might be a bit higher than shown. Also, temperature has an affect on these values. Upstream power levels go up if outside temperature goes up, so when temperature goes up during the day, you could end up with a problem if the upstream power levels sneak up above their tolerable max. Finally, check the cable F connector at the modem to make sure it's not loose or broken. The cable should not slip in the fitting and it should be at screwed to the modem at least finger tight or with a slight, snug tightening using a wrench.

The notices indicate a couple of reboots due to power reset. I assume you severed the electric connection to the modem to reboot it. If not, then you might check the electrical connection.

I'm not sure what the other Notices and Warnings mean, so others in this thread should comment about what they mean and if they're important.
--
There is nothing more deceptive than an obvious fact.

Sherlock Holmes in
The Boscombe Valley Mystery
A. C. Doyle
Strand Magazine, October 1891


Bterry89

join:2013-01-06
reply to bterry89

thank you for the info! I'll be sure to tell the tech that comes out tomorrow morning about this hopefully I can get it sorted out. I appreciate all of the insight and help from this community/forum!


n_w95482
Premium
join:2005-08-03
Ukiah, CA
reply to Streetlight

said by Streetlight:

I'm not sure what the other Notices and Warnings mean, so others in this thread should comment about what they mean and if they're important.

From what others have said, they can be ignored. The only anomaly in those logs would be the power resets. Hopefully those were from the OP and not a failing power supply.
--
KI6RIT

Bterry89

join:2013-01-06
reply to bterry89

Well the I told the tech what I had and he knew all to well about the SB6121 saying how he has had countless complaints about it and the reasoning being is that this modem will not dl the firmware. that comcast is sending out I guess.. and I asked him how long this has been going on and he said between 6-8 months. I dunno if this is only in certain areas or everywhere cause the reviews differ from it works great with comcast to it doesn't work at all.

so I asked him if he could suggest any other modems but he wasn't at liberty to say. SO needless to say I returned the modem already Glad its finally over!

Now I was wondering if anyone here could point me in the right direction for a new modem that will work with comcast?


ExoticFish

join:2008-08-31
Stuarts Draft, VA
reply to bterry89

Zoom 5341J


Bterry89

join:2013-01-06

great! thanks I'll look into also I wanted to know if anyone had thoughts on uBee DDM3513 Docsis 3.0 Cable Modem or Motorola SurfBoard SB6141 DOCSIS 3.0 Cable Modem or Motorola SURFboard Gateway SBG6580 DOCSIS 3.0 Wireless Cable Modem?



DrDrew
That others may surf
Premium
join:2009-01-28
SoCal
kudos:15
reply to bterry89

Are you using the power pack that came with the 6121? Can you post the DC power output on the power pack?


Bterry89

join:2013-01-06

it was 12V 750mA


andyross
Premium,MVM
join:2003-05-04
Schaumburg, IL
reply to bterry89

The upstream levels are at or near max for 3-channel bonded. The limit is 51dB for 64QAM, and 52dB for 16QAM. The one upstream is at the limit, and the other is very close.

Ideally, with bonded upstream, you want levels in the mid-40's.