Cable Modem Troubleshooting: Motorola SB5100

Light patterns, images, manuals and more helpful info for the Motorola SB5100 cable modem –

Manufacturer: Motorola Model: SB5100
Modem Light Indicators

Flashing – Startup diagnostics in progress.
On – Cable modem is powered on.


Flashing – Scanning for a downstream channel.

On – Downstream channel is connected.

Send Flashing – Scanning for an upstream channel.
On – Upstream channel is connected.

Flashing – Scanning for a network connection.
On – Startup process complete. Modem aqcuired.


Flashing or On – Transmitting or receiving data.


This light turns on when the standby button is pressed and standby
mode is activated. If this light is on, all other lights will be off.

Notes and Useful Information:

Installation and User Manual
(Requires Adobe Acrobat)

Motorola Product Website

34 thoughts on “Cable Modem Troubleshooting: Motorola SB5100”

  1. Pingback: Simplehelp » Cable Modem Index

  2. Hi, my modem is motorola SB5100 cable modem, I can’t connect to internet, lights not on, only power and receiver flashing, I try to install modem again but still nothing happening.

  3. Hi, my modem is motorola SB5100 cable modem, I can’t connect to internet, lights not on, only power and receiver flashing, I try to install modem again but still nothing happening.

  4. hello just woundering i have got that modem and when i go to install it , its checks all my connections and says it can not detect an ethernet card and i do not no what it is going on about could you please help me thanks .

  5. i have a very important question what is the ssid of motorola sb5100 its killing me i need it to conect mi wii to internet

    pleae respond

  6. I’m currently using my motorola sb5100 on my PC using windows XP, I’ve just bought a MAcbook pro and I can’t seem to install the modem onto it. Is it even compatable with MAC OS X?

  7. I’m currently using my motorola sb5100 on my PC using windows XP, I’ve just bought a MAcbook pro and I can’t seem to install the modem onto it. Is it even compatable with MAC OS X? and if so, how can I get it working?

  8. Perhaps a bit late, but for Ben: You need to unplug the power on the modem for about 10 seconds to make it work with a new computer unless you’re using a router

  9. zeeshan hussain

    Hi I got a very important question to ask, I got a motrola sb5100 cable modem currently using it on USB but I recently decided to change it, put an ethernet cable on because I need to, to be able to connect it to my router, everytime I try to install blueyonder driver it just says usb cable not found it can work with any but I did everything still it says, but about 4 years ago it worked with ethernet now I desperately need help from a professional please can you get back to me thank you, this is really urgent
    Yours sincerily
    zeeshan hussain.

  10. Hello-
    I have the SB5100 -when I restarted,only power led on and the “send” led is flashing.No other led’s on.Will not respond to restart.Any suggestions?? Thanks!


      My modem 5100 just went out like that. Now, when I try to power on it gaves me a flashing lights for maybe a second and goes off back. Try it again and again and get the same results. What to do next?

  11. evelyn what you should do is unplug the modem from the wall wait 30 seconds then plug it back in. that should help with your problem and if it does call you local internet provider.

  12. Im a Canadian user whose ISP issues these modems out with the service. I went ahead and bought a modem off ebay so I wouldnt have to keep renting it from my ISP but the American made modem won’t work on my PC with my ISP. Any ideas? Is it possible there is a lock of some type that prevents this modem from being used outside of the USA?

  13. je n’arrive pas à trouver le SSID pour configurer ma ds , j’utilise le connecteur wifi usb nintendo et j’ai un modem motorola SBV5121E, pouvez-vous m’aider

  14. Oiii eu tenhu um moudem SB5100 mas esta blokeado, teria como eu desblokear o sinal dele, como ? i teria como eu usar o moudem sem o ligar o cabo coax?
    Eu qeria saber se esse moudem ainda presta i tem como uzar, ou pode ir para o lixo.Vlw!

  15. Hello, i have an issue with this model, it seems that when i turn on the modem this loads the lights normaly, but after 3 flashes of the ‘PC\ACTIVITY’ light, only the Power light is on and the RECIVE and SEND lights start flashing both at same time, i dont recive any kind of signal from the router, i had it off for 4 days thinking may be overheating, do you know a solution or any kind of help that may solve my issue?

  16. Hi, I have a question about this SB5100. Can I connect 2 computer to internet at the same time using both of the connection (USB & ethernet)? I tried before but only 1 computer that can connect to the internet. The manual said that I can do it, does it need any other settings?

  17. For you Hans Malik, maybe it means you to have a router in order to conect more than 1 pc with the modem, i try as well but everyone told me that it can only hold 1 IP so i had to buy a router for more computers in a network, i assume you have to buy one.

  18. j’ai un moderm, a chaque fois que j’essaie de l’utilisser pour avoir l’acces a l’internet je ne peut pas et on me demande de voir un technicien .pouvez-vous m’aider a resoudre ce probleme

  19. I am using a Motorla SB5100 modem with a splitter (TV & internet) to connect to Comcast. Using Windows XP. I keep losing connection. How can I tell if it is the cable or my modem? TV on the splitter is fine. Thanks for any help.

  20. About two weeks ago, my four year old Motorola SB5100 cable modem started losing connection (required reboot) more frequently. Now, if I turn the computer off (wireless router remains on) I NEVER have an internet connection when I reboot the computer, and several times I have lost connectivity during a session. Rebooting (unplug SB5100 power, wait 10 sec., plug power in again) always restores the internet connection. In the past, need to reboot was infrequent. Cable connection is shared with TV (splitter) and TV signal is fine. Any thoughts, or should I just trash the thing and buy a new cable modem? Any recommendations on brand or model?

  21. P.S.: When Internet Explorer reports it cannot open a web page (connection has been lost) I check SB5100 and proper lights are on as though everything is fine.

  22. chuck, I have same issues and what I have been doing is cutting coaxial 1 inch back @ connector that goes into modem and the silver wires need to get pulled back (away from modem), make sure you peel back silver insulation also, and dont let any silver tiny wires get exposed outside of connector. This ongoing issue I have hasnt been corrected by my provider (cablevision). They have no clue. They really suck balls. But anyway, try to carefully put connector back on properly. I might have a drop off of electricity, which might crash it, but I also notice that internet explorer is always trying to send report and thats when I crash.

  23. Hola tengo una duda con mi modem Motorola SB5100 en PC/Activity siempre esta parpadeando pero el color no es verde, es naranja a que se debe esto y como lo puedo arreglar? Gracias por sus respuestas :)

  24. hi my SB4100 cable modem internet is moving really slow when i first brought the modem the internet was fine but a few days ago i started to experience really slow internet can any one help me resolve my problem please thank you

  25. Hola tengo un problema con mi modem SB5100 lo que pasa es que quiero que este funcione con 2 equipos pero al parecer mi USB no funciona, tengo que activar algo? o tengo que contatarme con mi suministrador de red y/o del equipo modem?

    espero respuesta

    Daniel Ruiz
    Pto. Vallarta; Jal.

  26. hola amigos tengo un cable modem sb5100, pero mi sistema operativo es w7 quisiera saber si son compatibles o existen los controladores para ello ?

    de antemano gracias espero una contestacion pronto.

  27. As a general rule everyone:
    If you DO NOT have 4 solid green lights, it’s a signal issue:
    Check connections, bypass splitters(if you can), power cycle modem.
    You should call your cable/DSL company for this one.
    Standby light on:
    Press standby button (on top of modem)
    Power light NOT solid green.
    Plug it in.
    Before doing anything below, turn OFF your firewall. If you accidentally blocked, say, IE, then you won’t get online no matter what you do. If you turn off your firewall and you can get online, then check firewall settings. Specifically, blocked programs.

    The lights look exactly like the picture above, but you can’t get online:
    Is a router connected?
    Yes – bypass it and power cycle modem
    No – run a ping test in the command prompt to see where the connection is failing
    4 reply from’s – Network card ok.
    4 of anything else – check network card and driver
    Ping This is the modem
    4 replies means your computer is talking to the modem
    4 of anything else – connection from computer to modem failed
    Check/swap ethernet cable
    Blow out NIC driver
    Ping Testing connection to Yahoo
    4 replies means your computer is online
    Check browser settings
    Clear cache/cookies
    Try another browser if you have one installed
    If the previous ping tests were good, but this one fails, ping to yahoo’s IP address –
    If this is good, problem is on the computer – Not my area of expertise.
    If this fails, then problem is the modem not talking to the internet.
    Check standby button: light pattern should match above.
    Reset everything: if still fails, modem may need to be replaced.

    Troubleshooting and diagnosing internet problems can be very lengthy. Most of the time a simple power cycle of your modem/router will fix the connection so always try that first. If you don’t understand any of the steps above, then call your cable/DSL company. To be honest, most follow a script that will cover most basic troubleshooting including most of the steps above.

    Good luck! Hope this helps.

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