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CoolBreeze2's avatar
CoolBreeze2
Follower
May 03, 2019

CM500-100NAS upstream channels

I lost Internet connection several times today. I power cycled the modem. I'm able to access the Internet after the power cycle.

I had Comcast send the Reset signal. I was able to access Internet after the Reset.

I lost connection again. I called Comcast. They ran tests. All came back good.

The rep asked how old the modem was. I told him about 3 years (I purchased it in Dec 2015).

The rep suggested the electronics might be failing and suggested I buy a new modem.

I just ordered the "NETGEAR Gigabit Cable Modem (32x8) DOCSIS 3.1 | for XFINITY by Comcast, Cox. Compatible with Gig-Speed from Xfinity (CM1000-1AZNAS) "

 

Then I looked at the modem Event Logs (that's just a portion):

 

019-5-3, 11:04:08 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=40:5d:82:ee:a0:c8;CMTS-MAC=80:e0:1d:03:1d:d0;CM-QOS=1.1;CM-VER=3.0;
2019-5-3, 11:03:10 Critical (3) Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=40:5d:82:ee:a0:c8;CMTS-MAC=80:e0:1d:03:1d:d0;CM-QOS=1.0;CM-VER=3.0;
2019-5-3, 11:02:56 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=40:5d:82:ee:a0:c8;CMTS-MAC=80:e0:1d:03:1d:d0;CM-QOS=1.0;CM-VER=3.0;
2019-5-3, 11:02:50 Critical (3) SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=40:5d:82:ee:a0:c8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2019-5-3, 11:02:49 Critical (3) Unicast Ranging Received Abort Response - Re-initializing MAC;CM-MAC=40:5d:82:ee:a0:c8;CMTS-MAC=80:e0:1d:03:1d:d0;CM-QOS=1.0;CM-VER=3.0;
 
 

Any ideas?

 

Thanks, Ed

1 Reply

  • FURRYe38's avatar
    FURRYe38
    Guru - Experienced User
    May 03, 2019

    If the new modem doesn't report these critical entries like the 500 does then you can presume the CM500 is faulty. Be sure there are no splitters between the modem and ISP service box. 

     

    If the ISP has checked the signal and it's good up to the modem and the modem still causes problems, it's the modem. The new modem should be good for you.