Equipment (Modems,Gateways)
Modems, Gateways, and Networking Devices
Male IT Specialist Holds Laptop and Discusses Work with Female Server Technician. They're Standing in Data Center, Rack Server Cabinet is Open.
KtecTim
Occasional Visitor

Netgear CG3000DCR getting too hot taking out internet and phone?

UPDATE: Appears to be a wiring fault to or in the building or other issue. The modem wasn't the problem just a symptom.

 

Until the modem is power cycled. Then it will work for ~1hr and crash again. It seems if room temperature goes above 85* the downstream power on the modem starts to nose dive until it drops the connection. Odd behavior but I've tried and tested everything else in the office.

 

Tried to get comcast tech to replace modem and he wouldn't/couldn't do it?

 

Has anyone else had this odd issue with this modem before. all the other network gear in the same room can take the heat...and it isn't excessively hot.

 

I should mention the phone EMTA is a separate arris device that is taken out when the netgear fails. It is odd behavior but I wonder if the netgear isn't introducing noise into the line, they are attached to the same splitter in the room. Comcast Tech Donahue spent a good deal of time re-running a cable to the outlet and really tried to nail down the issue for us, but it was at the end of the day and by that point the problem had subsided because of cooling room temperatures.

 

@Comcast_John - We've worked together before on some issues, any thoughts here?

 

Thanks,

 

Tim

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8 REPLIES 8
Forum Contributor

Re: Netgear CG3000DCR getting too hot taking out internet and phone

I have one of these modems in a cabinet that definitely gets above 85 at times and have no problem with it

 

This is going to sound strange but I would suspect your power adapter.  These "wall wart" AC adapters are just garbage.  I have replaced many of them in the past on network gear that was misbehaving.  The only way to test them is with a very accurate DMM that is wired in parallel with the load on, followed by an oscilloscope to check for ripple.   I know it sounds heat related but give it a try.  Check voltage and polarity on the existing adapter and find one to swap it with.

KtecTim
Occasional Visitor

Re: Netgear CG3000DCR getting too hot taking out internet and phone

I will give it a try. As this is comcast owned equipment I'll leave it to them to change the adapter. I should mention that aiming a fan at it seems to have solved 98% of the problem. Could be the power adapter over heating as well though, I'll stick an IR thermometer on it when I get a chance.

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KtecTim
Occasional Visitor

Re: Netgear CG3000DCR getting too hot taking out internet and phone

it seems if the phone is used it will also cause the modem to stop responding to pings. I'm wondering if there isn't an issue w/ the EMTA? This is an odd issue. Perhaps the EMTA is taking the downstream signal outside of what the netgear likes. There are a large number of taps between the modems. Downstream power is ~-2.0 - -6.0dba which seems on the lower end.

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KtecTim
Occasional Visitor

Re: Netgear CG3000DCR getting too hot taking out internet and phone


@tmittelstaedt wrote:

I have one of these modems in a cabinet that definitely gets above 85 at times and have no problem with it

 

This is going to sound strange but I would suspect your power adapter.  These "wall wart" AC adapters are just garbage.  I have replaced many of them in the past on network gear that was misbehaving.  The only way to test them is with a very accurate DMM that is wired in parallel with the load on, followed by an oscilloscope to check for ripple.   I know it sounds heat related but give it a try.  Check voltage and polarity on the existing adapter and find one to swap it with.


bought a better power brick. The old one was HOT.

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KtecTim
Occasional Visitor

Re: Netgear CG3000DCR getting too hot taking out internet and phone

still rebooting and dropping connections every once in a while, once or twice a day. no where near what it was doing and not taking out the internet requiring a power cycle of the modem, however from time to time it seems that the 3 out of 4 of the upstream channels aren't locked. Probably will have the equipment swapped.

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Forum Contributor

Re: Netgear CG3000DCR getting too hot taking out internet and phone

Make sure when a tech comes out to replace the gear that they -throughly- check out signal levels.

KtecTim
Occasional Visitor

Re: Netgear CG3000DCR getting too hot taking out internet and phone

Comcast tech came out and replaced the modem. Turns out, isn't the modem...They've also replaced the line to the modem and EMTA and while things have improved I am still getting abysmal signal quality to the Internet modem and on days over 93 degrees F the modem will drop connections (I notice it when I am connected to our VPN that the VPN connection will die and I won't be able to reconnect for a few minutes or sometimes the modem needs to be power cycled before I am able to regain a connection.

 

It seems that the phones have quit dropping calls in the office tho so that is a big plus. I'm thinking there is a bad cable splitter perhaps that is somewhat heat sensitive at the moment causing the issue.

 

I should mention that even though it isn't very warm today I am still getting a poor upstream connection according to the modem gateway summary -> cable modem page.

 

 

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Forum Contributor

Re: Netgear CG3000DCR getting too hot taking out internet and phone

Keep calling and complaining.  If you have bad signal levels at the modem on hot days then have it escalated.  Obviously a tech will have to be there on a hot day to find whatever it is in the street that has broken down but just complain until you get a smart one.

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