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CM1200 upstream led blinking continuosly.
3 of 4 upstream channels not working. Reset to factory default no help. Seems to be common issue with this model.
Please post a copy and paste of the modems connection status page.
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.
Be sure to power OFF the modem for 1 minute them back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Modems/m-p/1530376#M12853
requency 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 Startup Procedure
Procedure Status Comment Acquire Downstream Channel 765000000 Hz Locked Connectivity State OK Operational Boot State OK Operational Security Enabled BPI+ IP Provisioning Mode Honor MDD honorMdd(4) Downstream Bonded Channels (Partial Service)
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables 1 Locked QAM256 32 765000000 Hz 3.6 dBmV 43.3 dB 0 0 2 Locked QAM256 1 579000000 Hz 4.6 dBmV 43.7 dB 0 0 3 Locked QAM256 2 585000000 Hz 4.5 dBmV 43.7 dB 0 0 4 Locked QAM256 3 591000000 Hz 4.9 dBmV 43.8 dB 0 0 5 Locked QAM256 4 597000000 Hz 4.3 dBmV 43.5 dB 0 0 6 Locked QAM256 5 603000000 Hz 4.5 dBmV 43.6 dB 0 0 7 Locked QAM256 6 609000000 Hz 4.5 dBmV 43.6 dB 0 0 8 Locked QAM256 7 615000000 Hz 4.1 dBmV 43.4 dB 0 0 9 Locked QAM256 8 621000000 Hz 4.5 dBmV 43.6 dB 0 0 10 Locked QAM256 9 627000000 Hz 3.9 dBmV 43.4 dB 0 0 11 Locked QAM256 10 633000000 Hz 4 dBmV 43.5 dB 0 0 12 Locked QAM256 11 639000000 Hz 3.9 dBmV 43.4 dB 0 0 13 Locked QAM256 12 645000000 Hz 3.7 dBmV 43.3 dB 0 0 14 Locked QAM256 13 651000000 Hz 4.1 dBmV 43.5 dB 0 0 15 Locked QAM256 14 657000000 Hz 3.6 dBmV 43.3 dB 0 0 16 Locked QAM256 15 663000000 Hz 3.9 dBmV 43.4 dB 0 0 17 Locked QAM256 16 669000000 Hz 3.8 dBmV 43.4 dB 0 0 18 Locked QAM256 17 675000000 Hz 3.6 dBmV 42.5 dB 0 0 19 Locked QAM256 18 681000000 Hz 3.7 dBmV 43.3 dB 0 0 20 Locked QAM256 19 687000000 Hz 3.5 dBmV 43.2 dB 0 0 21 Locked QAM256 20 693000000 Hz 3.6 dBmV 43.3 dB 0 0 22 Locked QAM256 21 699000000 Hz 3.4 dBmV 43.3 dB 0 0 23 Locked QAM256 22 705000000 Hz 3.7 dBmV 43.3 dB 0 0 24 Locked QAM256 23 711000000 Hz 3.4 dBmV 43.1 dB 0 0 25 Locked QAM256 24 717000000 Hz 3.4 dBmV 43.2 dB 0 0 26 Locked QAM256 25 723000000 Hz 3.5 dBmV 43.3 dB 0 0 27 Locked QAM256 26 729000000 Hz 3.2 dBmV 43 dB 0 0 28 Locked QAM256 27 735000000 Hz 3.9 dBmV 43.4 dB 0 0 29 Locked QAM256 28 741000000 Hz 3 dBmV 42.9 dB 0 0 30 Locked QAM256 29 747000000 Hz 3.4 dBmV 43.1 dB 0 0 31 Locked QAM256 30 753000000 Hz 3.2 dBmV 43.1 dB 0 0 32 Locked QAM256 31 759000000 Hz 3.1 dBmV 43 dB 0 0 Upstream Bonded Channels (Partial Service)
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 1 Locked ATDMA 1 5120 Ksym/sec 17600000 Hz 46.5 dBmV 2 Not Locked Unknown 2 0 Ksym/sec 17600000 Hz 0.0 dBmV 3 Not Locked Unknown 3 0 Ksym/sec 30400000 Hz 0.0 dBmV 4 Not Locked Unknown 4 0 Ksym/sec 36800000 Hz 0.0 dBmV 5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV Downstream OFDM Channels
Channel Lock
StatusModulation /
Profile IDChannel
IDFrequency Power SNR /
MERActive Subcarrier
Number RangeUnerrored
CodewordsCorrectable
CodewordsUncorrectable
Codewords1 Locked 0 ,1 ,2 159 300000000 Hz 5.0 dBmV 43.9 dB 1108 ~ 2987 214435541 12816736 0 2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0 Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power 1 Not Locked 0 0 0 Hz 0 dBmV 2 Not Locked 0 0 0 Hz 0 dBmV Extended Upstream Transmit Power Enable Extended Upstream Transmit Power
Current System Time:Thu May 27 14:39:46 2021System Up Time:01:53:04
New cable to house, modem is located where cable inters the house.
Spectrum Tech pointed out the blocked upstreem channels.
numerous dropoffs throughout the day.
Has the modem been factory reset since installation.
What is the ISP speed package up and down you pay for.
Ya your upstream channels are not being locked in, for me on a 1Gb/50Mbps service I have 4 upstream channels locked in i believe.
If yours isn't locking in, i'd get the ISP to send out a tech on site and have them take a closer look. Any splitters on the line? Bad cabling or terminatior or splitters can cause this as well.
Be aware that Spectrum is notorious for not doing anything with user owned modems. There very hard to work with. So you may not get any great help. They probably won't update the modems FW. Which FW version is on currently on the modem?
If you seem to get no help with spectrum, you may want to rent one of there modems for short period of time, see if there modems do the same thing or not. If they do they they would have to correct the issue. Then you could probably put the CM modem back online.