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Philadelphia, PA
reply to trent

Re: [Signals] SB6121 new firmware messed up my upstream!

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US bonding is back!
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error log
I think mb See Profile was right about the overlap of firmware update and signal problems. The firmware might not be the source of my problems after all, maybe!

I returned home tonight, and found upstream power to have dropped to 54dBmV, but no channel bonding on upstream.
But after a reset and restart upstream channel bonding returned (3 channels like before) and upstream power is now 51dBmV on all channels. This is just within the recommended levels according to the FAQ, and higher than what I used to have (47-49dBmV).

I haven't had the chance to call Comcast yet. Should I still call regarding my upstream power? or is it OK now?

What does the warning message mean? I don't recall seeing a "MIMO Event" related message before with the old firmware.


Folsom, CA
i dont know what the mimo means. also the tlv-11 who knows

Schaumburg, IL
reply to trent
For 3-stream bonding, the max for 32 and 64QAM is 51dB. For 16QAM, it's 52dB.

So, you are still at the limit since all 3 of your channels support 64QAM.

In the pipe 5 by 5

Mount Laurel, NJ
reply to trent
said by trent:

I haven't had the chance to call Comcast yet. Should I still call regarding my upstream power? or is it OK now?

If everything is working for now, I would wait to call (I know how you feel trying to deal with them sometimes -lol). I've had times where the upstream power mysteriously jumped lile +5 for a few days, then went down to a better level than I had before the jump up. So it could be a coincidence since your firmware update that they just happen to be replacing something down the line that will clear up the level soon.

As for the error log, it's just normal operation, apparently. I see the same entries often enough too.


reply to trent
Hi Trent,
I too have been having issues since purchasing the SB6121 and called comcast about the issue. They sent out a tech and he thought my incident was due to a faulty network adapter (onboard nVidia 10/100/1000).

He tried the modem with his laptop and the network was stable and was able to connect to the internet. I also have a netbook but the adapter is 10/100 and it has held a stable internet connection since his departure until the evening when i powered it down (have not been home since this morning so unsure about during the day today).

It might not be your issue but it something to look into 1) try a different computer/laptop/netbook to see if you get a stable signal 2) look at your network adapter and try a 10/100 adapter if you have one to see if it is related to 1000 speed adapters.

I am not a expert in any way/shape/or form but these are things that I have thought might be the problem.