Our Arris S33 has worked like a champ for nearly 2 years.  Then, one evening two weeks ago, the modem suddenly dropped its connection to our ISP, Optimum.  There was no general service outage, and neither rebooting; repowering, nor factory resetting the modem helped--it remained unable to lock to an upstream channel signal, though it could lock to one downstream channel (channel 28).

I next disconnected the modem and tried reconnecting it to the cable at the point where the cable first enters our house--ahead of any other equipment or splits.  Still no joy…  The S33 gave the same result--no ability to lock to an upstream channel.

I then contacted Optimum support, and they could not remotely communicate with the modem either, which convinced me that either there was a problem in the signal somewhere between the road and our house OR that the modem had somehow failed.  An in-home Optimum service call was arranged.

The tech who showed up confirmed everything stated above.  He then swapped-in a new (Altice) rental modem, which he was able to successfully provision.  So, it appeared my S33 had indeed bitten the dust.  BUT...

Preferring to always purchase my own equipment rather than paying the ISP $15 (net of taxes and fees) every month to rent theirs, I picked-up a brand new Arris S33.  And, guess what… It too refuses to lock and cannot be provisioned by Optimum!  The Altice rental unit still works fine though.

What’s going on here?!  Any ideas how I can troubleshoot this most frustrating issue?  (I’m not big on conspiracies, but it is odd that our S33 just suddenly died after 2-years of exceptional service, and that a brand new S33 replacement won’t connect either.  Nevertheless, an Optimum-supplied rental unit connects readily.)

Any advice/guidance will be most appreciated!