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  1. #1
    b4serenity@gmail.com
    Guest

    Comcast / Motorola sb5100 cable modem dropping connection...

    I have broadband cable internet service from Comcast and I've been very
    happy with it until this past week. I've been having intermitant
    service to the net and it's really bugging me! It will work fine and
    the online light will be on the external modem and then it will just be
    off and no internet for my family (and biz). Then, it will just come
    back on again after a few minutes, maybe stay on for hours then off
    again for awhile.

    I've talked to Comcast and we did a powerdown reset on the computer and
    modem and he could tell on his end what my modem was trying to do (but
    not succeeding in doing = to get online) and he said that the signal
    was good to the house and that many people on my street were on at that
    very moment w/o any complaints. He had me test the cable channels and
    they were all fine as well. A new (mega thick) line was run to our
    house just a few months back (worked fine after the cable was
    installed). So he said it must be the modem.

    We own our modem so they offered to have us signup for their rental
    service ($3?/mo) but he wasn't sure if there would be a service
    /installation fee to deliver and set it up. I told him I'd just buy
    another one myself.

    Am I smart in doing this or should I just pay their fee and have them
    do it so the servicing is all on them? I worry (and have heard about)
    about them using some cheap modems that actually don't work as reliably
    or as fast as the Moto Surfboard SB5100 that I now have. Yes, the irony
    of that last staement about my modem being reliable has hit me!

    I have some info (an error log and some specific numbers but I'm not
    sure which ones are relevent here) from a Motorola diagnostics site if
    that could help anybody help me.

    Before I fork over my money on a new modem could it be anything else?

    Thanks so much for the help!!!!


  2. #2
    Agent_C
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    On 10 May 2006 05:37:36 -0700, b4serenity@gmail.com wrote:

    >[...]many people on my street were on at that
    >very moment w/o any complaints.


    They always say that... Don't take that as a given, as the tech you're
    speaking to has no idea what other people are complaining about.

    Ask your neighbors if they're having the same problem.

    A_C

  3. #3
    Dave
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    Can you access the modem to see the levels yourself?


    <b4serenity@gmail.com> wrote in message
    news:1147264656.303593.97980@i40g2000cwc.googlegroups.com...
    >I have broadband cable internet service from Comcast and I've been very
    > happy with it until this past week. I've been having intermitant
    > service to the net and it's really bugging me! It will work fine and
    > the online light will be on the external modem and then it will just be
    > off and no internet for my family (and biz). Then, it will just come
    > back on again after a few minutes, maybe stay on for hours then off
    > again for awhile.
    >
    > I've talked to Comcast and we did a powerdown reset on the computer and
    > modem and he could tell on his end what my modem was trying to do (but
    > not succeeding in doing = to get online) and he said that the signal
    > was good to the house and that many people on my street were on at that
    > very moment w/o any complaints. He had me test the cable channels and
    > they were all fine as well. A new (mega thick) line was run to our
    > house just a few months back (worked fine after the cable was
    > installed). So he said it must be the modem.
    >
    > We own our modem so they offered to have us signup for their rental
    > service ($3?/mo) but he wasn't sure if there would be a service
    > /installation fee to deliver and set it up. I told him I'd just buy
    > another one myself.
    >
    > Am I smart in doing this or should I just pay their fee and have them
    > do it so the servicing is all on them? I worry (and have heard about)
    > about them using some cheap modems that actually don't work as reliably
    > or as fast as the Moto Surfboard SB5100 that I now have. Yes, the irony
    > of that last staement about my modem being reliable has hit me!
    >
    > I have some info (an error log and some specific numbers but I'm not
    > sure which ones are relevent here) from a Motorola diagnostics site if
    > that could help anybody help me.
    >
    > Before I fork over my money on a new modem could it be anything else?
    >
    > Thanks so much for the help!!!!
    >




  4. #4
    b4serenity@gmail.com
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    Does any of this help any?

    /////////////////////////////
    Downstream Value
    Frequency 687000000 Hz Locked
    Signal to Noise Ratio 36 dB
    Power Level -10 dBmV
    The Downstream Power Level reading is a snapshot taken at the time this
    page was requested. Please Reload/Refresh this Page for a new reading

    Upstream Value
    Channel ID 3
    Frequency 31000000 Hz Ranged
    Power Level 52 dBmV
    ////////////////////////////////////

    ERROR LOG
    Time Priority Code Message
    2006-05-10 13:34:47 3-Critical R005.0 Started Unicast Maintenance
    Ranging - No Response received - T3 time-out
    2006-05-10 12:24:22 3-Critical R002.0 No Ranging Response received -
    T3 time-out
    2006-05-10 12:23:57 3-Critical T001.0 SYNC Timing Synchronization
    failure - Failed to acquire QAM/QPSK symbol timing
    2006-05-10 12:23:43 3-Critical D005.0 TFTP failed - request sent -
    No Response
    2006-05-10 12:22:33 3-Critical R007.0 Unicast Ranging Received Abort
    Response - Re- initializing MAC
    2006-05-10 12:21:54 3-Critical R002.0 No Ranging Response received -
    T3 time-out


  5. #5
    Bit Twister
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    On 10 May 2006 12:16:22 -0700, b4serenity@gmail.com wrote:
    > Does any of this help any?
    >
    > /////////////////////////////
    > Downstream Value
    > Frequency 687000000 Hz Locked
    > Signal to Noise Ratio 36 dB
    > Power Level -10 dBmV
    > The Downstream Power Level reading is a snapshot taken at the time this
    > page was requested. Please Reload/Refresh this Page for a new reading
    >
    > Upstream Value
    > Channel ID 3
    > Frequency 31000000 Hz Ranged
    > Power Level 52 dBmV


    at a glance you seem to be riding on the end of the power level specs.
    Here are suggested working ranges for solid operation. Values are from mine:

    Motorola Surboard SB5120 QAM 256 (Working range)
    Down Power -4 dBmV (-10 and +10 dBmV)
    SNR 37 dB (higher than 33dB)
    Up Power 48 dBmV (30 and 55dBmV)


    Anytime you lose the connection, get the values.

  6. #6
    b4serenity@gmail.com
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    First of all thanks so much for the help!!

    I only get these values when I'm online by connecting to a Moto site I
    saw in one of these posts. When my modem goes ofline I can't get these
    numbers

    Does it look like the modem is bad or is it saying that I'm getting a
    fairly weak (barely strong enough) signal?


    Thanks again!!


  7. #7
    b4serenity@gmail.com
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    OK, maybe we're on to something. I checked all the connections again
    but this time ran the cable to the modem directly from the wall w/o
    going through the splitter that they installed when they hooked up my
    dvr box in the same room. My down power level went up 3 dbs to -7.
    Seems a little low but not right on the bottom like it was. I'll try it
    like this for awhile and see if I get dropped. Maybe the modem is
    actually fine and they need to do something about the signal splitter.

    On the signal splitter it says 2-way splitter 5-1000mhzand on each of
    the two split connectors it says -3.5 db. Not sure what that means
    exactly but is it a coincidence that my signal rose 3 db w/o it? Can I
    just get a different value splitter?

    Thanks agin!!

    John


  8. #8
    Ed Nielsen
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    While the -10dBmV downstream is perfectly fine, I would be a little
    concerned about the +52dBmV transmit level. Two possibilities are:
    1) Temperature. It is possible that as the day progresses, the
    increase in temperature increases the attenuation of the cable
    sufficiently to push that transmit power beyond its limit, which
    typically is about 56-58dBmV.

    2) At some point, noise is getting into the return path, which causes
    your cable modem to transmit at a higher level than it otherwise would.
    The 2 biggest types of noise that can disrupt the upstream path are
    ingress and impulse noise. Ingress is stuff leaking into the cable
    system from the outside world. The most common causes of leakage are
    loose/substandard/corroded connectors, poorly shielded cable,
    substandard passive devices (splitters, taps). These are all part of
    the drop system. Impulse noise can be electrical noise getting into the
    cable system if there is insufficient filtering at some point where the
    2 have something to do with each other, such as a cable modem plugged
    directly into a wall outlet without the benefit of a surge power strip.
    Vacuum cleaners and blow dryers (things that cause sparklies on your
    TV when turned on) are also sources of impulse noise.

    Something is causing your cable modem to shout loud enough to be heard
    by the CMTS. Sounds like sometimes it has to shout so loud that it
    can't be heard.

    I would call and have a tech come out and figure out why your transmit
    is as high as it is.


    CIAO!

    Ed N.

    b4serenity@gmail.com wrote:
    > Does any of this help any?
    >
    > /////////////////////////////
    > Downstream Value
    > Frequency 687000000 Hz Locked
    > Signal to Noise Ratio 36 dB
    > Power Level -10 dBmV
    >
    >
    > Upstream Value
    > Channel ID 3
    > Frequency 31000000 Hz Ranged
    > Power Level 52 dBmV
    > ////////////////////////////////////


  9. #9
    b4serenity@gmail.com
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    Redid some splitters/connections. So far I'm still online just fine and
    here are the newest readings:
    Downstream Value
    Frequency 687000000 Hz Locked
    Signal to Noise Ratio 38 dB
    Power Level -2 dBmV
    The Downstream Power Level reading is a snapshot taken at the time this
    page was requested. Please Reload/Refresh this Page for a new reading

    Upstream Value
    Channel ID 3
    Frequency 31000000 Hz Ranged
    Power Level 44 dBmV


  10. #10
    Ed Nielsen
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    That 44dBmV is a beautiful thing!


    CIAO!

    Ed N.

    b4serenity@gmail.com wrote:
    > Redid some splitters/connections. So far I'm still online just fine and
    > here are the newest readings:
    > Downstream Value
    > Frequency 687000000 Hz Locked
    > Signal to Noise Ratio 38 dB
    > Power Level -2 dBmV
    > The Downstream Power Level reading is a snapshot taken at the time this
    > page was requested. Please Reload/Refresh this Page for a new reading
    >
    > Upstream Value
    > Channel ID 3
    > Frequency 31000000 Hz Ranged
    > Power Level 44 dBmV
    >


  11. #11
    Dave
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    Yes, those are all good levels.


    <b4serenity@gmail.com> wrote in message
    news:1147359489.933125.120900@j73g2000cwa.googlegroups.com...
    > Redid some splitters/connections. So far I'm still online just fine and
    > here are the newest readings:
    > Downstream Value
    > Frequency 687000000 Hz Locked
    > Signal to Noise Ratio 38 dB
    > Power Level -2 dBmV
    > The Downstream Power Level reading is a snapshot taken at the time this
    > page was requested. Please Reload/Refresh this Page for a new reading
    >
    > Upstream Value
    > Channel ID 3
    > Frequency 31000000 Hz Ranged
    > Power Level 44 dBmV
    >




  12. #12
    Junior Member
    Join Date
    May 2009
    Posts
    1
    Quote Originally Posted by b4serenity@gmail.com View Post
    Does any of this help any?

    /////////////////////////////
    Downstream Value
    Frequency 687000000 Hz Locked
    Signal to Noise Ratio 36 dB
    Power Level -10 dBmV
    The Downstream Power Level reading is a snapshot taken at the time this
    page was requested. Please Reload/Refresh this Page for a new reading

    Upstream Value
    Channel ID 3
    Frequency 31000000 Hz Ranged
    Power Level 52 dBmV
    ////////////////////////////////////

    ERROR LOG
    Time Priority Code Message
    2006-05-10 13:34:47 3-Critical R005.0 Started Unicast Maintenance
    Ranging - No Response received - T3 time-out
    2006-05-10 12:24:22 3-Critical R002.0 No Ranging Response received -
    T3 time-out
    2006-05-10 12:23:57 3-Critical T001.0 SYNC Timing Synchronization
    failure - Failed to acquire QAM/QPSK symbol timing
    2006-05-10 12:23:43 3-Critical D005.0 TFTP failed - request sent -
    No Response
    2006-05-10 12:22:33 3-Critical R007.0 Unicast Ranging Received Abort
    Response - Re- initializing MAC
    2006-05-10 12:21:54 3-Critical R002.0 No Ranging Response received -
    T3 time-out
    How do you get this?

  13. #13
    Andrew Rossmann
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    [This followup was posted to comp.dcom.modems.cable and a copy was sent
    to the cited author.]

    In article <1147264656.303593.97980@i40g2000cwc.googlegroups.com>,
    b4serenity@gmail.com says...
    > I have broadband cable internet service from Comcast and I've been very
    > happy with it until this past week. I've been having intermitant
    > service to the net and it's really bugging me! It will work fine and
    > the online light will be on the external modem and then it will just be
    > off and no internet for my family (and biz). Then, it will just come
    > back on again after a few minutes, maybe stay on for hours then off
    > again for awhile.


    When the modem is offline, what lights are blinking? If the receive
    light just blinks continuously, it is trying to find the downlink signal
    (receive signal strength or too much noise.) If the receive light is
    solid, but the send light is blinking, it is trying to establish the
    uplink (same potential problems as downlink.)

    For a weak incoming signal, you can use a broadband compatible RF
    amplifier. These allow the upstream signal to pass with minimal loss. It
    should be placed as close to where the cable comes into your house as
    possible. I would avoid the Radio Shack crap amps and get the Motorola
    484095-001-00 amp if you can find it. A Google search will find alot of
    sites. It's also commonly available at Circuit City, but at full price.

    --
    If there is a no_junk in my address, please REMOVE it before replying!
    All junk mail senders will be prosecuted to the fullest extent of the
    law!!
    http://home.att.net/~andyross

  14. #14
    b4serenity@gmail.com
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    Andrew, and everyone else, thanks for all thew responses!

    When the modem is offline (no online light) the recieve light sometimes
    blinks first then usually turns solid and the send light blincks about
    once per second. The PC/activity light blincks at a faster rate and
    sometimes I've seen it solid. Obviously, the power light is on. Then
    for seemingly no rhyme or reason the online light will come on and
    everything is fine.

    I thought the problem was fixed yesterday when was mainly on
    especially after removing the 2 way splitter from the wall connection
    (moden on one end and TV on the other). That bumped my signal about
    3dbs and I stayed online longer than anytime in the last week. Then
    right b4 an ebay auctiuon was about to end (!!!) the modem went offline
    for the rest of the night. Then , this morning it's back on. I'm going
    to rework a splitter connection at the street/house connection and get
    another 3dbs. That should get my modem signal to about -4 or -5.
    Does it have anything to do with people coming back from work and using
    Comcast and lowering the signal (although I have lost the connection in
    the day time as well)? Are the numbers I posted too low and it's a
    Comcast signal problem? What's the minimum signal requirements for a
    reliable signal?

    Thanks again for the help!!!

    John


  15. #15
    b4serenity@gmail.com
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    I just saw a manual on the 5100 that states it's operating range as -15
    > +15db. So, maybe the signal from comcast is OK and it's the modem afterall?? This is not fun! What do you think?


    I may just buy the newer Moto 5120 at Wal-mart for under $60 and then
    if I still have problems get Comcast out here to increase the signal.
    Is it normal in some cases where the computer is not getting a strong
    enough signal for them to just run a seperate line to the house or is
    that always treated as more money either for the installation and/or
    monthly charges?


  16. #16
    Dave
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    I don't think the 5120 is any newer than the 5100. They just justed two
    different chipsets and gave them different model numbers.


    <b4serenity@gmail.com> wrote in message
    news:1147350284.753553.160650@g10g2000cwb.googlegroups.com...
    >I just saw a manual on the 5100 that states it's operating range as -15
    >> +15db. So, maybe the signal from comcast is OK and it's the modem
    >> afterall?? This is not fun! What do you think?

    >
    > I may just buy the newer Moto 5120 at Wal-mart for under $60 and then
    > if I still have problems get Comcast out here to increase the signal.
    > Is it normal in some cases where the computer is not getting a strong
    > enough signal for them to just run a seperate line to the house or is
    > that always treated as more money either for the installation and/or
    > monthly charges?
    >




  17. #17
    Chuck Reti
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connection...

    In article <1147264656.303593.97980@i40g2000cwc.googlegroups.com>,
    b4serenity@gmail.com wrote:

    > I have broadband cable internet service from Comcast and I've been very
    > happy with it until this past week. I've been having intermitant
    > service to the net and it's really bugging me!
    >---- snip ----<


    I posted a very similar problem to this group a few weeks ago, received
    a number of useful responses. Broadbandreports.com FAQs and forums are
    full of reports from others with similar problems, and good
    troubleshooting tips.
    Since I own my modem (Moto SB5100) I decided to contact Motorola tech
    support just to see what their story might be. When I read off values
    from the modem signal and log pages (which were somewhat better than
    yours), they said "those levels are terrible." Called Comcast, they sent
    a tech out, who put his signal meter on the line, claimed all was
    "within spec," and snugged up connections (no splitter in line, have a
    direct drop from the pole to the modem, separate from the video
    service). I showed him the modem's configuration pages with signal
    levels and logs with "3-critical" errors of every kind. He was curious
    how I was able to get that information on screen; he'd never seen _that_
    before, how did I do that? So, I knew I was sunk. Trying to convince
    Comcast something should be bumped up on their end, even just a bit,
    looks like a hopeless effort.
    --
    Chuck Reti
    Detroit MI

  18. #18
    Ron W
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connectio

    Sorry I can't help -- I started having similar problems a couple of
    days ago with my Motorola SB 5120 -- occasionally "Send
    Channel" light flashes. I suspect I can improve my situation
    with a little reduction in cable losses.
    My question: How do you access the cable signal levels? Is it
    available via a URL?
    Thanks.


  19. #19
    Bit Twister
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connectio

    On Tue, 30 May 2006 13:59:50 GMT, Ron W wrote:
    > Sorry I can't help -- I started having similar problems a couple of
    > days ago with my Motorola SB 5120 -- occasionally "Send
    > Channel" light flashes. I suspect I can improve my situation
    > with a little reduction in cable losses.
    > My question: How do you access the cable signal levels? Is it
    > available via a URL?


    http://192.168.100.1

    Values from mine:
    Motorola Surboard SB5120 QAM 256 (Working range)
    Down Power -3 dBmV (-10 and +10 dBmV)
    SNR 37 dB (higher than 33dB)
    Up Power 47 dBmV (30 and 55dBmV)

  20. #20
    Roy
    Guest

    Re: Comcast / Motorola sb5100 cable modem dropping connectio

    On Tue, 30 May 2006 13:59:50 GMT, no@spam.invalid (Ron W) wrote:

    >Sorry I can't help -- I started having similar problems a couple of
    >days ago with my Motorola SB 5120 -- occasionally "Send
    >Channel" light flashes. I suspect I can improve my situation
    >with a little reduction in cable losses.
    >My question: How do you access the cable signal levels? Is it
    >available via a URL?
    >Thanks.



    go to 192.168.100.1 from your browser, you should get the modem
    configuration manager. You cah look at signal and other things there.

    Roy

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