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zunka's avatar
zunka
Guide
Dec 08, 2024
Solved

Please Help CM1200 Modem Speed Slowdown require constant rebooting

For the last three weeks, my internet speed drops drastically from over 950 Mbps to 30 MBps.  Rebooting the modem restores the speed but lasts only for a day or two. 

 

There are many threads on similar topic, but I could not find one with a definitive solution. 

 

I have not changed anything for the last 2 years (i.e. cable, modem, PC, Netgear MR60 router, etc.). For the past couple of years, I did not have this issue and was consistently getting 900+ MBps speed.

 

My PC is connected via Ethernet cable to router.  Don't use WiFi.

 

I dread calling my ISP (Optimum in New Jersey). Dealing with them is my last resort as it is a really frustrating wild goose chase.

 

I have attached my logs. Hoping someone can help me.

 

Thank you in advance.

 

  • Ok, next time please post the cable connections and event logs from the CM modem so we can help check and ensure problems seen on a modem may not be modem related, may ISP signal related. All things needs to be check upstream first before claiming the modem is the problem.

     

    Enjoy. 

15 Replies

  • plemans's avatar
    plemans
    Guru - Experienced User

    You have a ton of errors in your line. A ton. 

    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.
    If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

    Try that first and if it doesn't help, then you do need to contact the isp

    • Kitsap's avatar
      Kitsap
      Master

      plemans wrote:

      You have a ton of errors in your line. A ton. 

      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.
      If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

      Try that first and if it doesn't help, then you do need to contact the isp


      Below is a good reference site to supplement plemans recommendations.  Duckware is technically very competent.

       

      https://www.duckware.com/tech/solving-intermittent-cable-modem-issues.html

       

       

      • zunka's avatar
        zunka
        Guide

        Pelman & Kitsap

         

        Thank you for your suggestions and the link to the website. 

         

        It looks like the connector for the cable from the pole to the house has some sort of water damage. It matches, at least to me, the pictures posted on the duckware website.

         

        Cable inside the house seems to be fine. I don't have any amplifiers. Only one splitter for a cable to my TV and Modem. Removing that didn't seem to have made any difference. 

         

        I need to call my ISP to check it out.   Optimum service is not good (that is an understatement). Will keep you guys posted after couple of days.

         

        Thank you.