I'm using an Motorola SB6121 modem. http://mydeviceinfo.comcast.net/device.php?devid=365 I have had it for several months. I have been on the 50mbs tier since last fall. My speed tests have been consistently in the 30 down 20 up range from a wired PC. I'm in Norcross near Harbins and Singleton area. My internal wiring is all RG6u 75 ohm cable.
A couple of weeks ago, my Internet went down. My modem's receive button was flashing "RECEIVEFLASHING - Scanning for a downstream (receive) channel connection". This means that I cannot find the Comcast server.
Knowing that nothing about inside wiring had changed in months, I knew this meant there was a problem somewhere outside of my home. I turned everything off for 10 seconds, unplugged the cable, etc, and still nothing. I have not had any outages that lasted longer than 30 minutes or were not known issues (comast issues only) in many months. In other words, things had been pretty stable for months. I had not had a service visit to my home in a few years, and that was because a tree limb took out my cable line from the pole and this was quickly resolved with a replacement cable.
So I call Comcast (on my cell phone since I use an IP phone) and they tell me to reboot, etc. The rep must have been new because she couldn't tell me anything about what she was doing and had to put me on hold multiple times. At the end of our conversation, she had to set up a service visit, which was days out.
The day before the visit, internet was still out! I rechecked my internal wires. I went outside where a few years back a Comcast rep had installed some sort of booster that has a 75 ohm cable coming into a transformer which connects to a regular 120v power outlet. There is only one cable connector. It does NOT go in and then out, just in, and from who knows where. So I unplug this "booster" outside, turn off my modem, and then plug the booster back in, then plug in the modem, and still nothing has changed with the modem.
About 30 minutes later, I reboot the modem again and viola! I run the speed test at http://speedtest.comcast.net/ and I am now getting 110 mbs down! Wow, I hadn't been getting anything over like 30mbs for some time even though I was on the 50mbs tier. Did the booster reboot have anything to do with the issue being resolved? I don't know. I cancelled the appointment 24 hours later as speeds were still around or near 100mbs.
Fast forward to today. Everything was fine earlier today. NO changes made on my end. And then late this morning, I am back to no connectivity again. I try the reboot of the modem, no luck there. I wait an hour, retry the modem reboot, and viola, 110mbs download again. Then 5 minutes later the connection was lost again.
After being out for a few hours, I came back and still no connection to the modem. So I try the unplug of the "booster" again. And low and behold, I have connectivity again, with the Receive and Send lights both being SOLID BLUE. This color means high speed. I check the speed test again, and now I am at 12mbs down and 13 mbs up, a far cry from the 100 down and 26 up that I had been getting the last couple of weeks. But at least I have some Internet connectivity!
So my question is, is the "booster" going bad? Is this thing interfering with the signal? Should it be replaced or removed? If a Comcast technician came over here, can they figure this out without wanting to re-wire my house inside? How do I contact Comcast support and not waste 25 minutes on the phone with them trying to explain what the issue is so that they will get someone over here to fix the issue?