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sb6121 losing partial connection


I have a pretty new sb6121 and it worked fine for about a month before it started having problems. Now, every day it has been losing partial connection to the internet. At about ~8 pm it will lose ability to connect to websites that I haven't accessed before it loses partial connection. For example, if I don't go to yahoo before it loses partial connection, I won't be able to get to yahoo. The websites I've already visited behave normally with unchanged speeds, but any new connections will just behave like I don't have internet. The only way to fix it is to power off the modem and power it back on. Soft reboot from the IP doesn't seem to do anything.

If it matters, I turn the modem off with a power switch when I don't use it.

ISP: Wave broadband

Model Info:
Model Name: SB6121
Vendor Name: Motorola
Firmware Name: SB_KOMODO-
Boot Version: PSPU-Boot(25CLK) 1.0.12.
Hardware Version: 5.0
Firmware Build Time: Apr 17 2012 15:09:37

Signal Info after power cycling:
Channel ID 153  154  163  164 
Frequency 783000000 Hz 789000000 Hz 795000000 Hz 801000000 Hz 
Signal to Noise Ratio 35 dB 35 dB 35 dB 35 dB 
Downstream Modulation QAM256 QAM256 QAM256 QAM256 
Power Level
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
4 dBmV  4 dBmV  3 dBmV  4 dBmV  
Upstream Bonding Channel Value
Channel ID 3 
Frequency 31296000 Hz 
Ranging Service ID 5408 
Symbol Rate 2.560 Msym/sec 
Power Level 47 dBmV 
Upstream Modulation [3] QPSK
[2] 16QAM
[3] 64QAM
Ranging Status Success 
Signal Stats (Codewords) Bonding Channel Value
Channel ID 153  154  163  164 
Total Unerrored Codewords 107876847 107173496 107173314 107173569 
Total Correctable Codewords 15 4 11 22 
Total Uncorrectable Codewords 648 482 586 623 

If any one can help that would be great



Your downstream SNR is at the lower end of "satisfactory" but it should not be problematic as long as it's stable. Your downstream signal levels are fine. Your upstream power level is also satisfactory and your correctable/uncorrectable error counts are also fine.

Are you accumulating errors in your modem log? Also, have you tried using an alternate DNS? It could simply be an issue with your cable company's default DNS getting overwhelmed at that time of day.

Good luck!
"The dog days are over... The dog days are done..."


Thank you for helping.

I don't think my modem error logs are accumulating. Although, I am not certain.

If you would like to see it, here is a partial log from yesterday (6/13/2013) about the time it usually goes down (~8pm). I have some entries from the year 1970 scattered around the log, which I find strange, so I excluded those.

Jun 13 2013 19:50:09 5-Warning Z00.0 MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1;CM-MAC=38:6b:bb:17:c5:28;CMTS-MAC=00:13:5f:05:ee:9c;CM-QOS=1.1;CM-VER=3.0;
Jun 13 2013 19:46:33 6-Notice E112.0 SW download Successful - Via Config file
Jun 13 2013 19:44:52 6-Notice E102.0 SW Download INIT - Via Config file ^1/709A9924/HS15/RES/D3
Jun 13 2013 19:44:46 4-Error E109.0 Disruption during SW download - Power Failure
Jun 13 2013 19:44:01 3-Critical R04.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=38:6b:bb:17:c5:28;CMTS-MAC=00:13:5f:05:ee:9c;CM-QOS=1.1;CM-VER=3.0;
Jun 13 2013 19:43:35 6-Notice E102.0 SW Download INIT - Via Config file ^1/DC4AF977/HS15/RES/D3

Also, I'll try the alternative/dynamic DNS.

Thank you


reply to redteabag
The Motorola cable modems will timestamp an entry with a 1970's date during a reboot sequence, then after it synchs up it goes out and fetches the correct date. Maybe one of the programmers was fond of that decade? Another common Motorola issue is that at some point the log may begin to truncate and simply overwrite the last entry rather than adding a new entry to the list. Kind of annoying when you are troubleshooting something.

If you suspect that the modem is spontaneously rebooting it may be due to a loss of synch with your ISP's CMTS. Look for T-3 timeouts in the log and more of those 1970's dates. Your connection may be suffering from intermittent noise/ingress which would require a tech visit from your ISP to diagnose. I would expect to see a high error count in your log but note that your error count is respectably low in your first screenshot. However, if it's spontaneously rebooting, the error count gets reset to zero with each restart, so perhaps that's the explanation.

Hope you get it resolved!
"The dog days are over... The dog days are done..."