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[Signals] Motorola SB6141 gets stuck, requiring reboot?

Signal

Re: Motorola SB6141 gets stuck, requiring reboot?

Upstream power level too high.
+8 dBmV to +52 dBmV maximum for A-TDMA & TDMA (DOCSIS 3.0)
»Comcast High Speed Internet FAQ »What should my Signal Levels be?

I have a 5120, my neighbor has a 5100, which seems to be a lot more tolerant of signal levels out of range.

At 52dB, my 5120 will lose "online status". Within a few seconds, my Upstream can change by 6dB & go out of range.

A tech is coming tomorrow, but I found a poor connection at the dedicated modem wall jack. It was good for a year & never was touched. I re-terminated the best I could with no proper tools. Upstream is now 42dB, downstream is 4dB. Yesterday, it hit 52dB & went offline, even though online light was lit. Reboot & online light kept blinking.

Call CS, who will probably schedule a Tech for you.

A D3 modem can go up to 57dB on a single channel using 32QAM or 64QAM (58dB for 16QAM). D2's were only rated up to 54 or 55.

OP is at 256 QAM, so 52dB is the limit.

Thanks everyone for the replies. So it does sound like my upstream power levels are borderline, considering that there's two channels at 64QAM, each at 53 dBmV?

I logged my upstream power levels every 30 seconds since yesterday and it is always 53 dBmV. Haven't seen any jumps so far.

Thanks.

Re: [Signals] Motorola SB6141 gets stuck, requiring reboot?

Check and make sure it is not overheating. I have same model, had to return one to Bestbuy; overheated and quit working in less than two weeks of use. I keep my current one fan cooled. These modems are wayyyy hotter than any other I have used. Also, see reports that this modem overheats.

The last two days, there have been 2-3 incidents where the Internet gets really slow or stops working. The upstream power level hasn't changed from 53 dBmV. The modem logs show:

6-Notice      I502.0   Received REG-RSP while in REG-HOLD1 state;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.0;
5-Warning     Z00.0    MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.0;
3-Critical    R02.0    No Ranging Response received - T3 time-out;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.0;
3-Critical    R07.0    Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.0;
3-Critical    D12.2    DHCP failed - DHCP Solicit sent, No DHCP Advertise received;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.0;
 

Tech switched me from an 8-way splitter for a 4-way splitter and the upstream power level went from 53 to 49. He said that he's seen a lot of SB6141s with intermittent problems, so I returned it and got a SB6121 which now shows an upstream power level of 48. We'll see how it goes.

If possible, modem is supposed to be on the direct line from the pole or ped with no splitters. Mine enters the house, then goes through a no-loss tap (also called a directional coupler) & directly to the modem. The TAP side of the coupler goes to a 10dB amplifier, then to an 8-way splitter to feed all the rooms for TV. The coupler, amp & splitter are all Comcast supplied.

Your suggestions make sense (no-loss tap and trying to detect leaked signal) -- I don't understand why the Comcast tech didn't mention these suggestions. It seems like the tech did not consider me to have "bad" signal.

As to D3 modems not being required: I got postal mail and voicemail from Comcast saying to upgrade from a D2 modem or else service would stop working in the next few months. If not for these notifications, I would have stayed with my old modem for as long as possible.

Thanks for your replies.

Not all techs are aware of what a good signal is supposed to be or care about doing a proper job. Mine had a new piece of test equipment which tests the line from the house to the plant (head end, i.e CMTS) & sends an email to their supervisor with the results to insure the the job has been performed successfully.

The mailed notice I received in April said speeds were being increased to 25/4 at no additional cost. Don't know why you got the notice you did, unless you are paying for a higher tier than Performance. The tier you are paying for is shown on the back of the printed bill. For me, Performance is fast enough. It's about 4X faster than it was 10 years ago.

My tech did have some equipment that seemed to test from the coax to the plant. It seemed to test the entire spectrum / channels and everything was ok except for some TV mux channel that isn't related to the Internet. The tech did say that it sends some report to the company. I'm not sure if this is the same device you're describing, but it sounds like it could be it.

I tested my connection and it appears to be 30/10. The speed is not a priority to me (the only reason I have 30/10 is because of various free upgrades over the years, I've been using cable at various locations since it was 1.5/128). In addition to the notices, I had an online chat a few weeks ago with Comcast and they told me the same thing: get a new modem or else your service will stop working.

I'll see how the current setup goes... Thanks for your replies.