Modem keeps resetting...

[alexjohnson16]

I use Mediacom Cable Internet and my modem has been resetting quite a bit lately...

I called tech support and they sent out a guy and he said it's because I'm running my modem off a splitter that is hooked up to TV, and the power level keeps going up to >55dBmV...

I unhooked the splitter and the modem keeps resetting... The power level is still running around 54-55 dBmV...

Has this happened to anyone or does anyone know a way to fix it???

The modem is a SURFboard SB3100...

Thanks for any help...

 

[ScottMac]

Heat can cause resets - make sure the modem is clear of any obstructions that may block the airflow (and the wall wart / transformer too).

The transformer may be flakey ... if you know someone else with one, see if they'll swap you for diagnostic purposes.

A ground loop could be screwing things up. Try disconnecting the TV (at the closest connection to the modem) and see if it still resets. If it does, then disconnect it from the cable company connection too and watch to see if it still resets.

If you have access to a voltmeter, set it for "AC VOLTS" and touch one probe to the shield/screwring and the other probe to a known-good ground (water pipe or the outlet box (if you are in a recently built home)). If you see any significant voltage, call the cable company and let them track down the source.

Sometimes a broken shield will cause these symptoms (excessive noise). Try replacing the cables as possible.

Is there any chance that the power line that the modem is connected to is loaded with enough stuff that something turning on is causing a power dip?


That's all of the usual unusual stuff ... glitchy performance is usually either power, heat, or cabling.

Good Luck

Scott

 

[alexjohnson16]

Well, heat could very well be a factor... It's crammed between my monitor and my computer desk wall... I took it out to get some air, but it was still running at 55dBmV after a while...

I'm running straight to the modem now... Still running high, the guy from Mediacom said that it should run at about 52 dBmV and 55 is where it will start resetting itsself...

Is there any modem that can handle >55dBmV? I would like to run the TV and internet off the same jack... But if needed, I can unhook the TV...

 

[amdskip]

Is it a rented modem from them? If so, ask for a replacement and hope for the best. I use mediacom for my cable/internet too and the line in the house is split once when it comes to the house and then again when it goes into our computer room. Mediacom hooked it up this way when they installed it and it works pretty good.

 

[Univac]

Originally posted by: ScottMac
Heat can cause resets - make sure the modem is clear of any obstructions that may block the airflow (and the wall wart / transformer too).

The transformer may be flakey ... if you know someone else with one, see if they'll swap you for diagnostic purposes.

A ground loop could be screwing things up. Try disconnecting the TV (at the closest connection to the modem) and see if it still resets. If it does, then disconnect it from the cable company connection too and watch to see if it still resets.

If you have access to a voltmeter, set it for "AC VOLTS" and touch one probe to the shield/screwring and the other probe to a known-good ground (water pipe or the outlet box (if you are in a recently built home)). If you see any significant voltage, call the cable company and let them track down the source.

Sometimes a broken shield will cause these symptoms (excessive noise). Try replacing the cables as possible.

Is there any chance that the power line that the modem is connected to is loaded with enough stuff that something turning on is causing a power dip?


That's all of the usual unusual stuff ... glitchy performance is usually either power, heat, or cabling.

Good Luck

Scott

All good stuff. One thing that puts voltage on the cable line is an ac outlet with the hot and neutral swaped. The pc usually ends up with 50-55 volts on the case. If you are hooked up usb to the modem, it goes thru the outside sheilding of the usb cable to the cable modem, then to the cable. the cable is supposed to be grounded to your power service ground. So that finishes the circuit.

The modem will put up with it for a little while, but usually end up reporting 55db or so for the reverse,then stop working because they can't talk back anymore.

I found this out one rainy day,

 

[alexjohnson16]

Problems still happening...

I'm wondering... What causes voltage to the cable line???

I'm a stranger to all this... If I moved the cords running to the modem to where they come directly to the modem and don't contact any of the cords behind me desk if it would help...

Right now the cable cords (cat5, power, and cable line) run behind my computer and are touching all of my other cords...

Could it help to move the modem so the cords don't come in contact?