Customer Review

1,721 of 1,795 people found the following review helpful
4.0 out of 5 stars Modem NOT defective - Comcast conspiracy?, February 4, 2012
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This review is from: ARRIS / Motorola SurfBoard SB6121 DOCSIS 3.0 Cable Modem - Retail Packaging - Black (Personal Computers)
I felt compelled to write this to help those who will encounter the problems I faced (and mentioned here). I'm one of the many people who wanted to avoid renting a modem from Comcast and bought this modem based on the stellar reviews, only to find that on the day of installation/activation that it "didn't work". Didn't work meant experiencing the same symptoms that's been mentioned here several times - "modem connects but then resets/power cycles/disconnects itself within a few minutes." This happened to me on the day I activated my Comcast internet. The technician spent 1.5 hours trying to figure it out and ended up loaning me a Comcast modem (Motorola SB5120 DOCSIS2), which came up almost instantly and activated just as fast (go figure). He suggested I return this modem as it was defective, in his opinion. I didn't like this since the probability of this was very small. But I saw what I saw and could not get past the first page of Comcast self activation screen with this modem. Before the web page for self activation could proceed, after typing my account info and phone number, the modem would conveniently lose connection. At one point I did get to the next screen where it was scanning for devices, but the modem cut out thereby hanging the process. The modem was packed up in the box for return to Amazon when I couldn't shake how much this bothered me and by my bad luck. So I came back here and read pretty much every review. What I found was there's several people who experienced the EXACT same symptoms while trying several of the same modem. There were two reviews that stood out. One was from a person who mentioned the Comcast technician moaned when he saw it was this modem, indicating that the technician was aware of difficulties using this modem. The person mentioned that after 70 minutes of trying to get the modem to connect the technician advised him to leave the modem powered on and hooked up for awhile and to try activating later. The person did this and was successful in activating the modem. The other review was from a person who was admirably persistent. His review talks of several attempts to connect and refusal to accept that the modem was defective. He ended up leaving the modem power on and connected overnight so the modem could "download firmware". The next day he was able to activate after two attempts with Comcast self activation process. Lastly, I noticed for me that if I left the modem power on and connected but make no attempt to activate it via Comcast web site, the modem retains connection (via indicator lights) for prolonged periods of time. It only seems to lose connection when I try to activate. Based on this I felt something was broken with Comcast activation process specifically for this modem or perhaps Comcast was intentionally making it difficult to activate this modem to convince customers to rent a "reliable" modem from them. To be honest, it almost worked for me. After sitting there watching the technician agonize trying to get the modem to work, I was tempted to rent the modem and move on with life. So as one last hail Mary attempt, this is what I did:
1. Took the modem back out of the box and left the Motorola SB6121 power on and connected to cable outlet overnight just to entertain the possibility that some firmware or info needed to be downloaded to the modem and that for some reason it took a long time to do so.
2. The next morning I tried Comcast's self activation process.
3. Every time Win7's network icon in the lower right corner of my screen indicated that a internet connection was established (vs. exclamation mark) I immediately opened a IE windows and started the activation process with my account and phone #. The modem still lost connection when I did this but I kept on trying.
4. It took me about 4 tries to SUCCEED. Each time I tried, I started back on the account and phone # page. But each time it got further and further in the activation process.

Attempt #1: Account/phone # screen -> Retrieving Device Information -> Modem lost connection.
Attempt #2: Account/phone # screen -> Retrieving Device Information -> List of devices detected (screen showed my MOTR SB6121 modem and a DTV box both shown as "inactive" -> Modem lost connection. (A thing to note here is that Comcast's activation system could specifically identify this modem. This meant it was in their system and their system was able to communicate with it)
Attempt #3: Account/phone # screen -> Retrieving Device Information -> Listing devices detected -> Clicked "Rescan" device (modem)-> Hit "Next" to activate then got to screen where it said "Activating Device - This may take 10 minutes" -> Modem lost connection
Attempt #4: This isn't a real attempt because all I did is leave the web browser in the previous "Activating Device" screen and waited for the modem to re-establish connection again. I stepped away for a few minutes and when I came back I got a screen that stated "Device Activate" (and some other instructions that didn't matter) Hallelujah! Also note, NO phone calls had to be made to Comcast to activate this modem.

At this point, this modem which was losing connection all the time before, now had a seemingly rock solid connection!!! I'm using the connection now with this modem as I type this. I've did some basic testing, streamed video, surf the net,etc. NO LOSS OF CONNECTION! I did a speed test and I'm getting 25Mbps down and 3.8Mbps up.

Based on my experience so far, it is in my opinion that this modem works and is as good as what the majority of the reviewers here have stated. The problem lies in Comcast's self activation process which is suspicious. What doesn't make sense to me is the fact that modem can hold a solid connection if you didn't attempt to activate and after it's successfully activated. It was only when I tried to go through the self activate process that I saw problems. I can't say much about whether step #1 helped but it can't hurt to try. I mentioned it only to inform people of what exactly I did.

I truly hope this helps people. Amazon is top notch. This modem is now doing what it's suppose to do with no issues. I'll come back and update this review in about a month to report if it still holds true. I think it will but we'll see. And lastly, thanks for the people who shared their experiences here. If it weren't for them I would have returned the modem back to Amazon and go through the hassle of finding another modem or giving in and renting one from Comcast. I'm trying to pay it forward with this review.
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Tracked by 9 customers

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Showing 1-10 of 31 posts in this discussion
Initial post: Apr 15, 2012 7:41:28 PM PDT
Thanks for the post. With a bit of persistence I was able to follow your lead and get connected. I noticed the speed increase immediately. So far this modem has been worth the hassle.

In reply to an earlier post on May 23, 2012 12:37:23 PM PDT
david reese says:
I had the same experience, but with the SB6120, which unfortunately I sent back. It did seem to connect fine (eg the lights lit up) until I tried to activate it, so I tend to believe it's a Comcast issue.

Thanks for the detailed write-up

Posted on May 23, 2012 1:51:26 PM PDT
Kendoso says:
*** UPDATE ***
Glad I could help a few people. I just wanted to say that since I got my modem up and running, it's been working solidly with no connection drops or degradation in speed. This modem WORKS!! I just don't know why Comcast service has such a problem with this just getting it enabled initially. It's quite ridiculous and suspiciously discouraging. Good luck to all!

In reply to an earlier post on Jun 7, 2012 11:18:51 PM PDT
weezer1201 says:
When mine didn't come up immediately, I called comcast and their rep couldn't help either-the modem would reset and I would always end up back at the activation page. This worked for me, but I didn't even have to wait overnight. I left it on for about an hour and then just kept trying to get through the activation. Once you get through the activation steps, it works great.

As for the modem, the download increase isn't noticeable compared to my old sb5101 but I did get a 30% increase in upload and my latency/packet loss is around zero now(that could be the router which I updated at the same time). I would rather have gotten a sb6120 because I think they look much better, but I didn't want to pay twice as much.

Posted on Jul 31, 2012 1:28:52 PM PDT
August Luna says:
What jerks. Comcast sucks beyond all measure. They're totally jacking this thing on purpose. They have all these crazy policies and a terrible user interface and service reps with NO training and NO resources. But I have no choice. I'm not using satellite, so Comcrap it is. Thanks for all the advice and heads up!

Posted on Aug 23, 2012 7:04:35 AM PDT
J. Santiago says:
I would like to add to this comment. When I bought my own SB6120, I had to call comcast and insist that they connect me to a level 3 technician so they can provision my modem. They will need the mac address of the modem so their system would recognize it. When you activate a new modem, you need to do this. It took me about 1 hour for them to provision the modem. When it was up and running, i was clocking my speed at 80 mbps. Then comcast clock down my speed. Hope this helps to other comcast customers.

My knowledge base is level 2 network support in my company.

Posted on Oct 28, 2012 5:53:41 PM PDT
Thank you for your detailed report !

I have just substituted Comcast's Arris (brand name) modem that they leased to me, by this SB6121. However, I am not able to connect to anything (no activation page either but I would suppose it is because the previous modem was already activated).
Instead, my modem is blinking a red light. Here is the order:
- I plug it in
- power green
- (purple life signal)
- red life signal
- green down arrow and blinking blue up arrow
- blinking red globe
- red life signal blinks randomly throughout the above order and goes on to blink forever.
I wanted to know if any of you had had this symptom. And what color was your life signal icon.

Thank you !

In reply to an earlier post on Nov 9, 2012 2:04:12 PM PST
Awesome review man! I just had this problem with Comcast as well. I swear they try to screw me at every turn. They are constantly adding fees onto my bill and of course they are the only internet provider in my area, so I have to use them.

Posted on Feb 3, 2013 8:48:50 PM PST
Der Stang says:
I do believe the problem lied within the activation. When a purchased modem is added to an acct there are codes to put onto your acct that list it is purchased, then the device needs to have the MAC address applied to get the device working and activated. If it doesn't do this automatically due to all the cards falling into place perfectly, then a Comcast activation's rep has to help. The problem at that point is activation team is overseas and doesn't always have the proper knowledge with adding equipment to the right places in the correct tools, they just have the ability to send signals. The best trick is to say you have already talked to activation and they needed help with adding equipment and talk to the Internet Technical support (which is located in Huston, TX) if you get one of those reps, they will know what they are doing and have all the proper tools needed for help with activating your "owned" modem. I am sorry you had issues getting the device activated, and I understand the frustration. I am a former employee in their billing (quit to stay home with kids), so I promise you the information I am providing is the most accurate. I am looking forward to purchasing this same modem to help save money vs the modem rental too, since the employee discount has ended. However, as big as a company as Comcast is, they are still a great company to work for, and they provide great services, it's just the more customers a business has, the more people they need to hire to help customers, and sometimes that means reaching out to outsources who have a limited knowledge, and the job itself is tough dealing with angry customers, so they have a high turnover which means new hires often. If people were nicer to each other, people would enjoy working with customers, but customers feel they are entitled, and feel being rude and vicious will get their way. It's sad really. But no one is perfect, and no machine is either. So again I am glad to see you're patience was a success and it seems this is a good working modem, so thank you for your feedback.

Posted on Feb 18, 2013 12:00:27 PM PST
J. Duran says:
I wish I read this earlier. I just returned my Arris WBM760a Modem. It was used from Amazon. Replacing the same exact Arris Model that Comcast gave me. Everything started fine, went through the Comcast initial web page. It recognized my modem, went through 10 minutes, said everything was fine. Then it started dropping connection and resetting. It did that a couple of times, until it only got the Power LED to work!
Comcast tried to help me over the phone, but couldn't explain why and said it was the modem.
I will buy the Motorola SB6121, and will be ready for the BS. Thanks guys!!
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