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internet keeps dropping. sb8200 modem all lights turn off except for the top one
Hi
My internet keeps dropping. sb8200 modem all lights turn off except for the top one. I have to unplug it, wait 10 seconds and replug it in order for the other lights to come back. What is the issue?
current status and logs below:
| Procedure | Status | Comment |
| Acquire Downstream Channel | 495000000 Hz | Locked |
| Connectivity State | OK | Operational |
| Boot State | OK | Operational |
| Configuration File | OK | |
| Security | Enabled | BPI+ |
| DOCSIS Network Access Enabled | Allowed |
| Channel ID | Lock Status | Modulation | Frequency | Power | SNR/MER | Corrected | Uncorrectables |
| 20 | Locked | QAM256 | 495000000 Hz | -1.3 dBmV | 40.7 dB | 0 | 0 |
| 12 | Locked | QAM256 | 447000000 Hz | -0.4 dBmV | 40.9 dB | 0 | 0 |
| 13 | Locked | QAM256 | 453000000 Hz | -0.5 dBmV | 40.9 dB | 0 | 0 |
| 14 | Locked | QAM256 | 459000000 Hz | -0.5 dBmV | 40.8 dB | 0 | 0 |
| 15 | Locked | QAM256 | 465000000 Hz | -0.7 dBmV | 40.8 dB | 0 | 0 |
| 16 | Locked | QAM256 | 471000000 Hz | -0.9 dBmV | 40.8 dB | 0 | 0 |
| 17 | Locked | QAM256 | 477000000 Hz | -0.9 dBmV | 40.7 dB | 0 | 0 |
| 18 | Locked | QAM256 | 483000000 Hz | -1.2 dBmV | 40.6 dB | 0 | 0 |
| 19 | Locked | QAM256 | 489000000 Hz | -1.2 dBmV | 40.8 dB | 0 | 0 |
| 21 | Locked | QAM256 | 507000000 Hz | -1.0 dBmV | 40.0 dB | 0 | 0 |
| 22 | Locked | QAM256 | 513000000 Hz | -0.8 dBmV | 40.8 dB | 0 | 0 |
| 23 | Locked | QAM256 | 519000000 Hz | -0.6 dBmV | 40.9 dB | 0 | 0 |
| 24 | Locked | QAM256 | 525000000 Hz | -0.7 dBmV | 40.7 dB | 0 | 0 |
| 25 | Locked | QAM256 | 531000000 Hz | -0.7 dBmV | 40.7 dB | 0 | 0 |
| 26 | Locked | QAM256 | 537000000 Hz | -0.8 dBmV | 40.7 dB | 0 | 0 |
| 27 | Locked | QAM256 | 543000000 Hz | -0.8 dBmV | 40.7 dB | 0 | 0 |
| 28 | Locked | QAM256 | 549000000 Hz | -1.1 dBmV | 40.6 dB | 0 | 0 |
| 29 | Locked | QAM256 | 555000000 Hz | -0.9 dBmV | 40.6 dB | 0 | 0 |
| 30 | Locked | QAM256 | 561000000 Hz | -1.0 dBmV | 40.6 dB | 0 | 0 |
| 31 | Locked | QAM256 | 567000000 Hz | -1.2 dBmV | 40.4 dB | 0 | 0 |
| 32 | Locked | QAM256 | 573000000 Hz | -0.8 dBmV | 40.6 dB | 0 | 0 |
| 33 | Locked | QAM256 | 579000000 Hz | -0.7 dBmV | 40.6 dB | 0 | 0 |
| 34 | Locked | QAM256 | 585000000 Hz | -0.5 dBmV | 40.7 dB | 0 | 0 |
| 35 | Locked | QAM256 | 591000000 Hz | -0.6 dBmV | 40.6 dB | 0 | 0 |
| 36 | Locked | QAM256 | 597000000 Hz | -0.7 dBmV | 40.5 dB | 0 | 0 |
| 37 | Locked | QAM256 | 603000000 Hz | -0.9 dBmV | 40.2 dB | 0 | 0 |
| 38 | Locked | QAM256 | 609000000 Hz | -0.8 dBmV | 40.5 dB | 0 | 0 |
| 39 | Locked | QAM256 | 615000000 Hz | -0.9 dBmV | 40.5 dB | 0 | 0 |
| 40 | Locked | QAM256 | 621000000 Hz | -0.7 dBmV | 40.4 dB | 0 | 0 |
| 41 | Locked | QAM256 | 627000000 Hz | -0.8 dBmV | 40.4 dB | 0 | 0 |
| 42 | Locked | QAM256 | 633000000 Hz | -1.1 dBmV | 40.3 dB | 0 | 0 |
| 48 | Locked | Other | 688000000 Hz | -0.6 dBmV | 38.8 dB | 181267398 |
0
|
| Channel | Channel ID | Lock Status | US Channel Type | Frequency | Width | Power |
| 1 | 1 | Locked | SC-QAM Upstream | 17300000 Hz | 6400000 Hz | 44.0 dBmV |
| 2 | 4 | Locked | SC-QAM Upstream | 36700000 Hz | 6400000 Hz | 43.0 dBmV |
| 3 | 3 | Locked | SC-QAM Upstream | 30300000 Hz | 6400000 Hz | 43.0 dBmV |
| 4 | 2 | Locked | SC-QAM Upstream | 23700000 Hz | 6400000 Hz | 43.0 dBmV |
| 5 | 5 | Locked | SC-QAM Upstream | 41200000 Hz | 1600000 Hz | 44.0 dBmV |
| 05/26/2020 00:59 | 67061600 | 6 | "DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 2436694066 | 6 | "Honoring MDD; IP provisioning mode = IPv6" |
| 01/01/1970 00:00 | 84000100 | 3 | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 82000200 | 3 | "No Ranging Response received - T3 time-out;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 84000100 | 3 | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 82000200 | 3 | "No Ranging Response received - T3 time-out;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 84000100 | 3 | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 05/25/2020 08:44 | 82000200 | 3 | "No Ranging Response received - T3 time-out;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 05/25/2020 08:44 | 84000500 | 3 | "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 82000200 | 3 | "No Ranging Response received - T3 time-out;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 84000100 | 3 | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 82000200 | 3 | "No Ranging Response received - T3 time-out;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 84000100 | 3 | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 05/25/2020 06:44 | 82000200 | 3 | "No Ranging Response received - T3 time-out;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 05/25/2020 06:44 | 84000500 | 3 | "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 82000200 | 3 | "No Ranging Response received - T3 time-out;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
| 01/01/1970 00:00 | 84000100 | 3 | "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;" |
| 05/16/2020 06:36 | 82000500 | 3 | "Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=14:c0:3e:01:cc:f1;CMTS-MAC=00:01:5c:65:14:7f;CM-QOS=1.1;CM-VER=3.1;" |
Accepted Solution
EG
Expert
•
111.5K Messages
5 years ago
Even though the signal stats looked o/k at that snapshot in time, the error log entries confirm that something is going on. Perhaps there is intermittent noise ingressing into the line(s) somewhere.
There are other signal stat figures that can't be read by the modem. They are the "Upstream Rx Power" (Upstream Receive Power Level), the "Upstream SNR Ch." (Upstream Signal To Noise Ratio), and the "Upstream ICFR" (In Channel Frequency Response). These are as equally important in diagnosing connectivity issues as are the modem's stats.
I'm going to escalate your issue to the Comcast corporate employees that are available to these boards. They can check the CMTS (Cable Modem Termination System) for any real time degradation and / or error reports, see your node / cable plant and modem health, and see whether or not everything is in the green zone. They can also see a history plot for the modem and poll for those upstream receive signal stats.
You should get a reply here in your topic. Good luck !
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XfinityAmira
Official Employee
•
4.2K Messages
5 years ago
Hello @acf1, thanks for reaching out to our Digital Care Team through our Forums page. I'm sorry to hear about the connection issues you have been experiencing. I can definitely see how inconvenient and frustrating that must be especially during these troubling times. I would love to assist you and further look into this on my end. Can you please send me a private message including your first and last name as it appears on the account?
To send me a Private Message, please click my name “ComcastAmira” and click “send a message".
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