Arris Surfboard SB8200 DOCSIS 3.1 Modem - SYNC timing synchronization failures

I’ve lived for years at 160Mbps without resetting my modem, an Arris Surfboard SB8200.

I needed 10Mbps up so upgraded to 300Mbps plan but ever since I’m finding myself having to reboot the modem every couple of days as I see the below error in the event logs. And my internet drops to just 15/8 or so which is a tell-tell that the error happened. A reboot brings me back to 300 service level.

This modem is the only thing plugged into coax lines, nothing else. I’ll post signal levels shortly but they seem within norms.

HELP!!! I hate paying more for worse service.


Date Time Event ID Event Level Description
11/26/2020 08:22 84000500 3 "SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=90:9d:7d:2e:34:39;CMTS-MAC=00:87:31:90:d9:60;CM-QOS=1.1;CM-VER=3.1;"
11/26/2020 08:10 2436694061 5 "Dynamic Range Window violation"
11/26/2020 08:10 82001100 5 "RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=90:9d:7d:2e:34:39;CMTS-MAC=00:87:31:90:d9:60;CM-QOS=1.1;CM-VER=3.1;"
11/26/2020 08:10 2436694061 5 "Dynamic Range Window violation"
11/26/2020 08:10 82001100 5 "RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=90:9d:7d:2e:34:39;CMTS-MAC=00:87:31:90:d9:60;CM-QOS=1.1;CM-VER=3.1;"
11/26/2020 08:10 2436694061 5 "Dynamic Range Window violation"
11/26/2020 08:10 82001100 5 "RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW;CM-MAC=90:9d:7d:2e:34:39;CMTS-MAC=00:87:31:90:d9:60;CM-QOS=1.1;CM-VER=3.1;"