I am trying to replace an older Arris cable modem with a new Arris SB6190. After numerous attempts, the "online" led continues to flash, and does not turn solid, even after 45 minutea or so. Connections are correct, the modem is supported at my Blast level (150 mbs), and I've upgraded modems previously with no issues. The problem persists even after a factory reset. Am I missing something, or should I return the modem? Is is possible that I need to call and register with Comcast BEFORE installing? Instructions don't say to, but only thing I haven't tried. Thanks for any help,
If your US/DS light is continuously flashing it means the modem isn't getting a sold connection with the headend server. The most common cause of this is that there is poor or no signal to that outlet. It is possible that your old modem is more tolerant of poor signal than your new one.
Hook up your old modem and check the signal levels. If they look okay, then your new modem should probably be replaced.