Modem randomly rebooting. VERY annoying.

Discussion in 'Networking & Security' started by Despotes, Jun 24, 2018.

  1. Despotes

    Despotes Gawd

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    I'm using an Asus N66U router with an Arris SB6190 cable modem. My modem will randomly reset itself every day. sometimes 3 or 4 times a day and others it may happen every couple of minutes. I tried unplugging both, shutting down the pc ect, but it has no affect.
    Here's a screen shot of the log when I lost internet connection. In this example, I lost my connection at 9:10-ish and at 10:55 -ish. Is there anything useful in the log?
    Are there any recomended settings in my router I can adjust if it's my router causing my modem to reset?
    Currently using Merlin's 380.61 firmware on the Asus.
    2nd pic only shows a few "Uncorrectables", but I've had thousands accumulated in just about one day. Is that normal?
     

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    Last edited: Jun 24, 2018
  2. bds1904

    bds1904 Gawd

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    Your downstream SNR is a little low but not bad. You aren’t getting an excessive amount of errors and your upstream power level is good.

    Do you have cable TV boxes too? If you don’t have tv boxes make sure that you don’t have a splitter at all, just a direct line from the drop to your modem.

    If you do have cable boxes and just have one splitter then add a 2-way splitter to the feeding coming into the house and put the leg of coax going to the modem on that and then the other output to the old splitter.

    If all this applies then the T3 timeouts likely are being caused by some kind of interference problem either inside your house or outside caused by another problem. If it’s just a low signal issue then you could ask to be upgraded to an RG-11 drop.
     
  3. Despotes

    Despotes Gawd

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    No cable TV box or splitters. So, it's likely the condition of the cable drop?
     
  4. bds1904

    bds1904 Gawd

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    Likely could be, typically an RG6 drop to the house is only good for 100-150ft. Any longer and it should be an RG11 drop.

    If your drop is already RG11 or is shorter than 150ft I would say there is a problem in the neighborhood. Edit: assuming you already did all the normal things like make sure all the connections are tight.
     
    Last edited: Jun 24, 2018
  5. Dead Parrot

    Dead Parrot [H]ard|Gawd

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    Don't overlook the possibility of power drops. A lot of wall warts suck at power filtration.

    Double check the grounds in your cable network box where their drop connects to your wiring. Might not hurt to undo and reconnect all the coax connections and check for corrosion.
     
  6. jardows

    jardows [H]ard|Gawd

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    I've seen a lot of goofy things causing modem reboots, but in the end, they are fairly simple machines, so not too much to troubleshoot.

    Your signals look good, I wouldn't worry about cable lines until you've tried other troubleshooting steps.
    Factory reset your modem. I believe this model comes with a reset button on the back. Just get a paper clip or similar, and push and hold the button for about 10-15 seconds
    If you can stand to have only one computer connected for a while, connect with just one computer and see if the modem still reboots. I've seen weird network activity cause it.
    As stated above, electrical power can cause issues. I've suspected power at the wall or the cheap AC/DC adapters used to be the cause of many issues, but never able to prove it. If you have a UPS, connect the modem to that.

    If it does seem to be on the line side, I've seen several MSO issues case it - bad connections at the CMTS, a faulty service trap, or other stuff that only the cable technician can look at.

    There's always the possibility that the modem is malfunctioning, so keep that in mind.
     
  7. Despotes

    Despotes Gawd

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    Just got home from work and checked the status. Isn't that really bad?
     

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  8. John721

    John721 [H]ard|Gawd

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    Getting thousands of uncorrectables in a 24 hour period consistently, along with the reboot issues you're having, would lead me to investigate further. I'd give your ISP a call. I had a similar issue myself a few years ago, and, once the repair work was done, I would generally see only a few dozen uncorrectables turn up in a day (which might have been an uncommonly good result).
     
  9. Shikami

    Shikami Gawd

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    Power and SNR too low (should be just a bit higher for both, optimally). Check the split if at right frequency, wiring, and their demarcation too for signal and power. You can always check at: http://www.dslreports.com/. A good place to find some information, and sometimes technical help on the provider's end.
     
    Last edited: Jul 4, 2018
  10. Ehren8879

    Ehren8879 Little Bitch 3

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    I think downstream power levels and SNR look good.

    Im wondering what his upstream SNR performance has been. But for that you gotta call your ISP
     
  11. mikepelchy

    mikepelchy n00bie

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    I was having a lot of issues with my modem rebooting every night at a certain time (give or take 10-15 minutes). Cable company was out many times checking over everything and we ended up noticing a spike on the meter when we unplugged a certain drop in the house. This drop was not actively connected to anything, just simply run from the basement up to a wall plate in a bed room. I have had the drop unplugged since and haven't had an issue since.