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CM-1000 Losing Connection, Comcast says can't diagnose during help call because not a comcast modem

New Poster

CM-1000 Losing Connection, Comcast says can't diagnose during help call because not a comcast modem

Starting 12/22 in the AM, I noticed most of our wifi network intermittently going down (Security System, Video, Wifi, ect.). We have been having some heavy rain, so I figured it was a neighborhood network issue. However, I never saw anything as far as outtages on the app. I went through the normal power cycle on the modem a few times, and even hard reset the router and set it back up (GT-AC5300). After some more troubleshooting, I realized it wasn't the router but the modem. It's a fairly new CM-1000, haven't had any issues with it so far. I never noticed it going through a reboot cycle, so I didn't think anything of it. I did notice on the xfinity app that whenever I was having an issue, it wasn't connected. I called for support, but they said since they have a current connection they couldn't diagnose the issue. Basically I'd have to call when it goes down. Also stated that since it wasn't a comcast product (Netgear), that they couldn't read any diagnostic data. I went in to the modem diagnostics and noticed a lot of critical items. I'm not very knowledgable on signal strength and power, so any guidance on where to go here I'd appreciate!

 

Here is the event log of the past 24 hours:

 

2017-12-23, 08:40:56

Warning (5)

REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Notice (6)

Honoring MDD; IP provisioning mode = IPv6

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 17:53:40

Critical (3)

Resetting the cable modem due to docsDevResetNow

2017-12-22, 17:49:50

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 14:14:06

Critical (3)

Resetting the cable modem due to docsDevResetNow

2017-12-22, 14:11:15

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 14:07:01

Critical (3)

REG RSP not received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 13:23:26

Critical (3)

REG RSP not received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 07:11:59

Critical (3)

REG RSP not received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 07:08:13

Critical (3)

REG RSP not received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 07:06:49

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 07:05:34

Critical (3)

REG RSP not received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 07:04:01

Critical (3)

REG RSP not received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

DHCP failed - DHCP Solicit sent, No DHCP Advertise received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

DHCP failed - DHCP Solicit sent, No DHCP Advertise received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

DHCP failed - DHCP Solicit sent, No DHCP Advertise received;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 07:00:02

Critical (3)

Resetting the cable modem due to docsDevResetNow

2017-12-22, 06:59:58

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:58:52

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:58:03

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:57:56

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:57:53

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:57:17

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:56:52

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:56:12

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:55:59

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-22, 06:55:54

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx:10;CMTS-MAC=xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1

 

Note: I removed the MAC addresses, but the CM-MAC and CMTS-MAC do not match.

 

Latest Log after a factory reset on the modem:

 

2017-12-23, 09:01:46

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx;CMTS-MAC=00:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-23, 09:00:19

Notice (6)

CM-STATUS message sent. Event Type Code: 3; Chan ID: N/A; DSID: E; MAC Addr: N/A; OFDM/OFDMA Profile ID: N/A.;CM-MAC=xx:xx:xx:xx:xx;CMTS-MAC=00:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

2017-12-23, 09:00:19

Warning (5)

Unicast DSID PSN startup error

2017-12-23, 08:59:49

Warning (5)

REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=xx:xx:xx:xx:xx;CMTS-MAC=00:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Notice (6)

Honoring MDD; IP provisioning mode = IPv6

Time Not Established

Critical (3)

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

Time Not Established

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=xx:xx:xx:xx:xx;CMTS-MAC=00:xx:xx:xx:xx:xx;CM-QOS=1.1;CM-VER=3.1;

Time Not Established

Critical (3)

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

 

Here are my current connection stats:

 

Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Starting Frequency

<tabindex=-1>Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 729000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only

<tabindex=-1>Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR / MER Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked QAM256 21 729000000 Hz 6.2 dBmV 40.3 dB 48754675 0 0
2 Locked QAM256 1 609000000 Hz 8.1 dBmV 41.0 dB 47253420 0 0
3 Locked QAM256 2 615000000 Hz 7.7 dBmV 40.9 dB 47261941 0 0
4 Locked QAM256 3 621000000 Hz 7.9 dBmV 41.0 dB 47271046 0 0
5 Locked QAM256 4 627000000 Hz 7.4 dBmV 40.9 dB 47280141 0 0
6 Locked QAM256 5 633000000 Hz 7.4 dBmV 40.6 dB 47285916 0 0
7 Locked QAM256 6 639000000 Hz 7.2 dBmV 40.7 dB 47299161 0 0
8 Locked QAM256 7 645000000 Hz 7.1 dBmV 40.6 dB 47307951 0 0
9 Locked QAM256 8 651000000 Hz 6.9 dBmV 40.5 dB 47317712 0 0
10 Locked QAM256 9 657000000 Hz 6.9 dBmV 40.5 dB 47326996 0 0
11 Locked QAM256 10 663000000 Hz 6.9 dBmV 40.4 dB 47336669 0 0
12 Locked QAM256 11 669000000 Hz 7.0 dBmV 40.6 dB 47345598 0 0
13 Locked QAM256 12 675000000 Hz 7.1 dBmV 40.1 dB 47355716 0 0
14 Locked QAM256 13 681000000 Hz 6.9 dBmV 40.3 dB 47363949 0 0
15 Locked QAM256 14 687000000 Hz 7.2 dBmV 40.6 dB 47373438 0 0
16 Locked QAM256 15 693000000 Hz 6.9 dBmV 40.2 dB 47382707 0 0
17 Locked QAM256 16 699000000 Hz 6.8 dBmV 40.2 dB 47380079 0 0
18 Locked QAM256 17 705000000 Hz 6.7 dBmV 40.5 dB 47410399 0 0
19 Locked QAM256 18 711000000 Hz 6.4 dBmV 40.4 dB 47419980 0 0
20 Locked QAM256 19 717000000 Hz 6.2 dBmV 40.3 dB 47428801 0 0
21 Locked QAM256 20 723000000 Hz 5.9 dBmV 40.3 dB 47430581 0 0
22 Locked QAM256 22 735000000 Hz 5.5 dBmV 40.2 dB 47438250 0 0
23 Locked QAM256 23 741000000 Hz 5.9 dBmV 40.2 dB 47444370 0 0
24 Locked QAM256 24 747000000 Hz 5.3 dBmV 40.1 dB 47449904 0 0
25 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
26 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
27 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
28 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
29 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
30 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
31 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0 0

<tabindex=-1>Upstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 1 35800000 Hz 49.5 dBmV
2 Locked ATDMA 2 29400000 Hz 50.0 dBmV
3 Locked ATDMA 3 23000000 Hz 50.0 dBmV
4 Not Locked Unknown 0 0 Hz 0.0 dBmV
5 Not Locked Unknown 0 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Hz 0.0 dBmV

<tabindex=-1>Downstream OFDM Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier Number Range Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Not Locked Unknown 0 0 Hz 0 dBmV 0 dB 0 ~ 0 0 0 0
2 Not Locked Unknown 0 0 Hz 0 dBmV 0 dB 0 ~ 0 0 0 0

<tabindex=-1>Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked Unknown 0 0 Hz 0 dBmV
2 Not Locked Unknown 0 0 Hz 0 dBmV

Current System Time: Sat Dec 23 09:17:13 2017 
Expert

Re: CM-1000 Losing Connection, Comcast says can't diagnose during help call because not a comcast mo

The upstream power is borderline / too high and may be intermittently fluctuating even higher out of spec. That can cause random disconnects, spontaneous re-booting of the modem, and speed and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.


New Poster

Re: CM-1000 Losing Connection, Comcast says can't diagnose during help call because not a comcast mo

Thanks EG!

 

I haven't had any critical event logs since the 23rd, which makes me suspect it may have been due to the weather. I did see a couple of Xfinity trucks across the street on the 24th, so perhaps they were working on some lines. I do have one main splitter in the attic that I'll check, splitting off the main into the house - one line going to modem and 2 going to cable tv box / additional room. It's a fairly new one that was replaced by Xfinity after a lightning strike, but I'll do what you suggest to see what may be causing the high upstream power! Thank you for the help!