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user_x5y7z0
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Thursday, March 20th, 2025 7:24 PM

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netgear docsis 3.1 mdem cm1000v2

Hi, I am now experiencing random (and often daily or 2-5x/day) frequent disconnects after several years of stable service with my Netgear DOCSIS 3.1 modem CM1000v2.

Sometimes, the modem reconnects itself, in a few minutes to a few hours.  When the system is not reconnecting, removing power to the modem and then booting usually connects successfully on the first attempt.

My modem hardware version is 2.02, and the firmware version is V10.01.07 (which Comcast indicates as the most recent update).  When connecting CAT 5 cable to my LAN on my PFSense router, I get up to 1.0GBPS max.  Using wifi, I get up to ~400 MBPS (max).

The event log for the Modem shows typical recurring errors:

1. UCD invalid or channel unusable;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
Another critical error: SYNC Timing Synchronization failure:
2. Failed to acquire QAM/QPSK symbol timing;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Any suggestions, or is it time to replace the modem?
Thanks, William

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1 year ago

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EG

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117.1K Messages

1 year ago

What do the modem's signal status values look like ? Please also copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

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EG

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117.1K Messages

1 year ago

@user_x5y7z0 

Try the Cable Connection button / tab.

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EG

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117.1K Messages

1 year ago

@user_x5y7z0 

Did you have a chance to try to obtain those signal values via that method ? Please respond right here in your topic on these public help forums. Thank you. 

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user_x5y7z0

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@EG​ 

Sorry to be slow...overloaded with other issues not related to networking, et al.

Here is the printout from the Cable Connection button and advanced tab:

Cable Connection
 
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</tabindex=-1>
Procedure Status Comment
Acquire Downstream Channel 469750000 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</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power SNR / MER Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked QAM256 4 469750000 Hz -0.8 dBmV 44.0 dB 775964593 15 0
2 Locked QAM256 1 451750000 Hz 0.8 dBmV 44.9 dB 775076233 18 0
3 Locked QAM256 2 457750000 Hz -0.4 dBmV 44.2 dB 775078653 22 0
4 Locked QAM256 3 463750000 Hz -0.6 dBmV 44.0 dB 775070937 9 0
5 Locked QAM256 5 475750000 Hz -2.2 dBmV 42.9 dB 775085756 9 0
6 Locked QAM256 6 481750000 Hz -4.7 dBmV 41.2 dB 775089483 19 0
7 Locked QAM256 7 487750000 Hz -5.1 dBmV 40.9 dB 775094740 16 0
8 Locked QAM256 8 493750000 Hz -3.2 dBmV 42.1 dB 775098381 27 0
9 Locked QAM256 9 499750000 Hz 0.5 dBmV 44.7 dB 775100864 12 0
10 Locked QAM256 10 505750000 Hz 1.1 dBmV 45.1 dB 775106282 10 0
11 Locked QAM256 11 511750000 Hz -1.2 dBmV 43.6 dB 775111139 10 0
12 Locked QAM256 12 517750000 Hz -5.5 dBmV 40.4 dB 775115477 8 0
13 Locked QAM256 13 523750000 Hz -6.8 dBmV 39.5 dB 775118587 19 0
14 Locked QAM256 14 529750000 Hz -5.6 dBmV 40.5 dB 775113337 17 0
15 Locked QAM256 15 535750000 Hz -4.7 dBmV 40.6 dB 775125115 18 0
16 Locked QAM256 16 541750000 Hz -7.1 dBmV 37.0 dB 775128312 25 0
17 Locked QAM256 17 547750000 Hz -7.6 dBmV 38.1 dB 775131861 12 0
18 Locked QAM256 18 553750000 Hz -4.0 dBmV 41.5 dB 775136174 11 0
19 Locked QAM256 19 559750000 Hz -2.0 dBmV 43.2 dB 775138332 5 0
20 Locked QAM256 20 565750000 Hz -2.4 dBmV 42.9 dB 775142979 6 0
21 Locked QAM256 21 571750000 Hz -0.6 dBmV 44.1 dB 775146872 8 0
22 Locked QAM256 22 577750000 Hz -0.4 dBmV 44.1 dB 775152778 8 0
23 Locked QAM256 23 583750000 Hz -0.4 dBmV 44.1 dB 775153348 13 0
24 Locked QAM256 24 589750000 Hz 1.1 dBmV 45.0 dB 775159203 10 0
25 Locked QAM256 25 595750000 Hz -2.1 dBmV 43.0 dB 775163850 14 0
26 Locked QAM256 26 601750000 Hz -2.2 dBmV 42.7 dB 775168389 12 0
27 Locked QAM256 27 607750000 Hz 0.7 dBmV 44.6 dB 775163011 3 0
28 Locked QAM256 28 613750000 Hz -0.1 dBmV 44.2 dB 775173473 5 0
29 Locked QAM256 29 619750000 Hz -0.6 dBmV 43.8 dB 775177368 3 0
30 Locked QAM256 30 625750000 Hz 1.1 dBmV 43.7 dB 775181059 5 0
31 Locked QAM256 31 631750000 Hz 1.8 dBmV 45.1 dB 775198548 3 0
32 Locked QAM256 32 637750000 Hz 1.2 dBmV 43.7 dB 775187979 10 0
<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power
1 Locked ATDMA 17 16400000 Hz 37.3 dBmV
2 Locked ATDMA 18 22800000 Hz 37.3 dBmV
3 Locked ATDMA 19 29200000 Hz 36.8 dBmV
4 Locked ATDMA 20 35600000 Hz 37.5 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</tabindex=-1>
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power SNR / MER Active Subcarrier Number Range Unerrored Codewords Correctable Codewords Uncorrectable Codewords
1 Locked 0, 1, 2, 3 193 957000000 Hz -16.2 dBmV 27.3 dB 148 ~ 3947 742129441 265839500 470514054
2 Not Locked 0 0 0 Hz -0.2 dBmV 0.0 dB 0 ~ 4095 0 0 0
<tabindex=-1>Upstream OFDMA Channels</tabindex=-1>
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 Mar 22 16:56:26 2025
System Up Time: 57:16:05
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I have not experienced any dropouts since 3/22 and the log is also free from any critical alerts that were seen on 3/20.

1 year ago

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