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Forum Discussion
CM500 - Upstream light is Amber
Hi there - my modem is a CM500 and just recently the upstream light has turned to solid amber which is causing me some connection issues. Below are my cable connections and event logs.Thank you in advance!
| nel | Lock Status | Modulation | Channel ID | Frequency | Power | SNR | Correctables | Uncorrectables |
| 1 | Locked | QAM256 | 14 | 243000000 Hz | 4.2 dBmV | 41.6 dB | 0 | 0 |
| 2 | Locked | QAM256 | 1 | 165000000 Hz | 4 dBmV | 41.9 dB | 0 | 0 |
| 3 | Locked | QAM256 | 2 | 171000000 Hz | 4.5 dBmV | 42.3 dB | 0 | 0 |
| 4 | Locked | QAM256 | 3 | 177000000 Hz | 4.6 dBmV | 41.9 dB | 0 | 0 |
| 5 | Locked | QAM256 | 4 | 183000000 Hz | 4.8 dBmV | 41.5 dB | 0 | 0 |
| 6 | Locked | QAM256 | 5 | 189000000 Hz | 4.9 dBmV | 42.3 dB | 0 | 0 |
| 7 | Locked | QAM256 | 6 | 195000000 Hz | 5.1 dBmV | 42.5 dB | 0 | 0 |
| 8 | Locked | QAM256 | 7 | 201000000 Hz | 5.1 dBmV | 42.2 dB | 0 | 0 |
| 9 | Locked | QAM256 | 8 | 207000000 Hz | 5.2 dBmV | 42.4 dB | 0 | 0 |
| 10 | Locked | QAM256 | 9 | 213000000 Hz | 5.1 dBmV | 41.7 dB | 0 | 0 |
| 11 | Locked | QAM256 | 10 | 219000000 Hz | 5.1 dBmV | 42.3 dB | 0 | 0 |
| 12 | Locked | QAM256 | 11 | 225000000 Hz | 5.1 dBmV | 42.2 dB | 0 | 0 |
| 13 | Locked | QAM256 | 12 | 231000000 Hz | 4.9 dBmV | 41.8 dB | 0 | 0 |
| 14 | Locked | QAM256 | 13 | 237000000 Hz | 4.6 dBmV | 41.7 dB | 0 | 0 |
| 15 | Locked | QAM256 | 15 | 249000000 Hz | 4.4 dBmV | 41.4 dB | 0 | 0 |
| 16 | Locked | QAM256 | 16 | 255000000 Hz | 4.5 dBmV | 41.2 dB | 0 | 0 |
| Channel | Lock Status | US Channel Type | Channel ID | Symbol Rate | Frequency | Power |
| 1 | Locked | ATDMA | 1 | 5120 Ksym/sec | 36800000 Hz | 43.8 dBmV |
| 2 | Not Locked | Unknown | 0 | 0 Ksym/sec | 0 Hz | 0.0 dBmV |
| 3 | Not Locked | Unknown | 0 | 0 Ksym/sec | 0 Hz | 0.0 dBmV |
| 4 | Not Locked | Unknown | 0 | 0 Ksym/sec | 0 Hz | 0.0 dBmV |
| Time | Priority | Description |
| 1970-1-1, 00:00:36 | Warning (5) | DHCP WARNING - Non-critical field invalid in response ;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.0;CM-VER=3.0; |
| 1970-1-1, 00:00:34 | Notice (6) | Honoring MDD; IP provisioning mode = IPv4 |
| 2024-11-20, 00:47:06 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:47:05 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:47:02 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:47:01 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:47:00 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:46:58 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:46:56 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:46:54 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:46:53 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:46:52 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:46:51 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:46:50 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:52 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:52 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:50 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:50 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:45 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:45 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:44 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:43 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:41 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:41 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:39 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:39 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-20, 00:45:38 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 2024-11-20, 00:45:37 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 2024-11-20, 00:45:21 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 2024-11-20, 00:45:16 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 1970-1-1, 00:00:21 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-11, 10:20:51 | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-11, 10:20:44 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 2024-11-11, 10:20:22 | Critical (3) | SYNC Timing Synchronization failure - Failed to receive MAC SYNC frame within time-out period;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 2024-11-11, 05:08:03 | Critical (3) | DHCP FAILED - Discover sent, no offer received;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-11, 05:07:53 | Critical (3) | No Ranging Response received - T3 time-out;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.0;CM-VER=3.0; |
| 2024-11-11, 05:07:26 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 2024-10-16, 10:28:08 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 2024-10-16, 10:28:04 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
| 2024-10-7, 08:41:10 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=28:80:88:c5:6e:88;CMTS-MAC=94:d4:69:55:9e:ad;CM-QOS=1.1;CM-VER=3.0; |
3 Replies
I forgot to add, I just tried a new coax cable this evening and it did not fix it.
Any Criticals, Errors or Warnings seen in the event logs needs to be reviewed and resolved by the ISP. Indicates a signal issue on the ISP line up to the modem.
Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box.
Be sure your using good quality RG6 coax cable up to the modem.
Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
Be sure to power OFF the modem for 1 minute then back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Modems/m-p/1530376#M12853
https://kb.netgear.com/24311/Power-level-guidelines-for-a-NETGEAR-cable-modem-router
https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html
https://highspeed.tips/docsis-events/Your logs indicate a line issue back to the ISP.
Follow the advise from above and see if it helps.
I recommend directly connecting the modem to the line that first comes into the house. That rules out things in the house causing issues such as the wiring in the walls/jacks/etc.
If that doesn't help, time to call the isp
