Xfinity/SB6190 Connection Diagnosis

  • 16 March 2024
  • 7 replies

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I am suffering repeated, intermittent loss of internet service, running an SB6190 on Comcast/Xfinity service.  I believe the problem is on the Comcast side, but would like to know how to confirm this.  I am very reluctant to call Comcast, given past customer service experiences.  Also, at this point, I am unable to log into my Surfboard simply because I don’t know the UserID or password.  So my questions are:


Was there a default password?

Are there symptoms or diagnostics that I could run to confirm that the modem is functioning correctly?

If I do a hard reset on the Surfboard will I be able to establish a new user ID/password?  Any advice on how to configure the device if that proves necessary?


Best answer by SURFboard Moderator 17 March 2024, 02:24

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7 replies


There is a small RESET button hole on the back of the modem.   A short hold reboots the modem.

A long hold, and I think its at least 30 seconds, will return the modem to factory.   You might have

to wait a while before the modem works again.     I would do a little research on the RESET button

for the SB6190.   It might clear up any bugs your having.   The default username is admin

and the default password is password.


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Any advice on reading the logs or other info to confirm that the Surfboard is operating as intended or see that the incoming signal is to blame?  (I am nearly totally ignorant on these things.)





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Here are some screenshots from a time when modem shows downstream good and upstream not.  (sometimes neither is good, I just didn’t capture it in time.


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As I checked the cable signal levels, under downstream channels, all the signals are in range.

But for the upstream channels, the power level should be greater than 45dbmv. Currently it is less than 45dbmv. I suggest you to contact your internet service provider and ask them to reprovision the modem with internet service provider to adjust the signals within a range.

Also to know the information about the event log, please contact internet service provider for further assistance.