Well, had Comcast a few years ago, but refused to pay the money for the modem rental, so purchased an SB6120. Which worked absolutely brilliantly for a week or so, then suddenly would NOT stay connected reliably for more than a few hours. Comcast came to my house 2-3 times, rewired everything in the house, but could not get it working. I ditched the modem, replaced it with a different brand and model, and it worked brilliantly. For a few days, then the same thing started happening. Was told it was the modem, replaced it AGAIN, and same issue.
Basically, the entire process, over the course of 6-7 weeks, felt like an absolute scam by the company to force me into renting one of their modems. Which I did - an SB6120, ironically - and the problem magically went away. I refused to endorse such practices, so ended up cancelling my acocunt, and switching to DSL. Which was much slower, but it was usable.
Usable until a couple of months ago, when my DSL provider (Sonic.net in Northern California) started requiring customers to use their own rental modems. About a month after that announcement, lo and behold, my internet access kept going down. Guess what they blamed it on?
I simply refuse to be forced to "rent" a modem so with reluctance, contacted Comcast. Had Performance with Blast installed, told them not to bother with the self install kit since I'd be purchasing my own modem, and the cable from the original install was still intact. Rep at the local office told me I HAD to take a self install kit, but to just return the equipment the next day (Assumedly so they could charge me the $15 fee). Picked up a Motorola SB6121, and it was working brilliantly for the past 3-4 days.
Until this morning.
Internet is down, dead, smashed to the four winds. Modem is connected to a latest gen Apple Airport Extreme wireless router. Disconnected the modem for 60 seconds to perform a hard reset, didn't work. Disconnected the Airport Extreme and connected my laptop directly to the modem, didn't work. Hard reset the modem, still didn't work. Directly connected the modem to my desktop, reset, didn't work.
Contacted Comcast, did an automated reset, didn't work. Spoke to a CSR, she manually reset it on her end, and said everything looked fine to her, but the problem persisted. Suggested it was the router, but mentioned I had directly connected the modem to two different computers, and the problem remained.
The odd thing in all of this is that I have a VOIP phone in my office (I work from home) that is currently functioning without issue. So I clearly have a connection of SOME sort.
Disconnected and reconnected my old DSL modem (thankfully hadn't contacted Sonic to disconnect yet) and everything is working swimmingly (at least for now) so I know the issue isn't my router or computer(s). Either something's wrong with Comcast, or something is wrong with the 4-day-old SB6121.
To make this worse, Comcast are saying a tech won't be available to come out and look at this until Wednesday, which isn't acceptable. So was hoping I could reach out here to see if anyone has any suggestions, beyond returning the modem and getting a replacement?
(And apologies for the long winded, somewhat venting post!)