My SB8200 had been working fine for more than a year and a half, but this morning, it went catatonic. Front panel lights were all still good, but the (separate) router could no longer see it. The router itself seemed fine. Rebooting the router made no difference. Rebooting the modem re-established the connection and everything was fine.
About an hour later, the modem went catatonic again. Another reboot, and everything was fine. This time I tried to log into the modem to see if there was any useful information in the event log. It told me my username or password was incorrect, which is highly unlikely since I use a password manager. After multiple attempts to log in, I had to use the last 8 characters of the serial number as the password. That worked, and I’ve reset the password.
The event log had no useful information, but I noticed the time of the most recent event was more than an hour earlier--before the most recent reboot! I checked the status page, and it says the system time is about 62 minutes earlier than all of my other internet-connected devices (including my router). If it were exactly 60 minutes off, I’d assume that it just didn’t acknowledge daylight saving time. Nothing in the web interface seems to allow me to set the time, time zone, DST, or NTP server.
About an hour later, the modem was unreachable for the third time. (And again, there was no indication of a problem on the front panel lights.) Another reboot brought it back to life again. But the system time is still 62 minutes early, which feels like a suspicious coincidence given the approximately hourly failures.
I have an even newer Arris modem, but I haven’t switched to it yet since activation/provisioning with Comcast/Xfinity is always a multi-day cascade of fail that I haven’t yet mustered the will to take the plunge again..