70stang's profile

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5 Messages

Tuesday, January 31st, 2023 3:53 PM

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New Motorola MB8611 Modem will not connect to Xfinity

New Motorola MB8611 Modem.

Spent 2 hours on the phone with Xfinity tech support trying to get this new modem to connect.

I currently have the $15 monthly rental modem/router unit. I have the router turned off and I am using a TP LINK AX1800 router which has a lot better WIFI coverage and better signal strength.

Anyway, after 2 hours, cycle power and factory reset, Xfinity gave up, and I had to reinstall the rental modem. All lights on modem cycle during power up and appear normal after a few minutes, the "Online" globe symbol is solid blue. the upstream/downstream arrows are solid blue.

NOTE:

I am using the same coax cable and same Ethernet cable. This is a simple swap, one coax, one Ethernet and power. Rental unit reconnected and I was back online.

Also, Xfinity wants user to use web application from Cell phone to setup modem. Without a working modem I have no WIFI. Want engineer thought this one through!!!, Takes about 30 minutes to get past the automated Xfinity answering service to get a real person. Not good, this should be a simple phone call change mac address and connect.

Log files in MB8611 modem show:

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=XX:XX:XX:XX:XX:XX;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

CM-MAC was correct I just put XX in place of numbers. CMTS-MAC is always 00. Which indicates to me something not correct on Xfinity side.

Problem Solver

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948 Messages

2 years ago

I had the same thing happen, tech couldn’t see my modem etc, I had just removed a xb8, finally he had me reboot my modem and magically he could see it…

New Poster

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5 Messages

2 years ago

We rebooted the MB8611 twice, and did factory reset once, I can get the Xfinity screen on Computer and put in my phone number and the passcode they texted me but that is it. Some data is being passed but I cannot get on the internet with it. 

Expert

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110K Messages

2 years ago

@70stang 

CMTS-MAC is always 00. Which indicates to me something not correct on Xfinity side.

FWIW here. It could be either side. It's 00 because the modem is not talking to the CMTS for whatever the reason may be, so it can't see / indicate the CMTS's MAC addy.

New Poster

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5 Messages

2 years ago

I called Motorola support and they told me this happens all the time with Xfinity when activating via a phone call to tech support.  Motorola told me to call back and ask for a supervisor and explain the situation and have the modem properly activated. I did this it took me 20 minutes to get a person on the phone and 10 minutes later my MB8611 was working. 

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