Question NETGEAR Nighthawk AC3200 won't connect. Please help!

[ktrainhurricane]

Hi, I have a NETGEAR Nighthawk AC3200 Wi-Fi Router with DOCSIS 3.1 Cable Modem (Model C7800). I purchased this new a little over a year ago, and had it connected in my house with Xfinity. I've since sold that house and moved. Now, when trying to connect this in the new house (also with Xfinity), it's not working.

Spoke with Xfinity on the phone in an attempt to troubleshoot the issue(s), and they ended up saying that the modem is bad; however, I find this hard to believe because I had been using it with no issues at all just recently. And all I've done since moving was unplug it, place it back into the box, and then took it out and plugged it back in.

I did notice that on the modem itself not all of the appropriate indicator lights are lit. I have attached a photo below. Any and all help is greatly appreciated! Thank you.

 

[kanewolf]

Hi, I have a NETGEAR Nighthawk AC3200 Wi-Fi Router with DOCSIS 3.1 Cable Modem (Model C7800). I purchased this new a little over a year ago, and had it connected in my house with Xfinity. I've since sold that house and moved. Now, when trying to connect this in the new house (also with Xfinity), it's not working.

Spoke with Xfinity on the phone in an attempt to troubleshoot the issue(s), and they ended up saying that the modem is bad; however, I find this hard to believe because I had been using it with no issues at all just recently. And all I've done since moving was unplug it, place it back into the box, and then took it out and plugged it back in.

I did notice that on the modem itself not all of the appropriate indicator lights are lit. I have attached a photo below. Any and all help is greatly appreciated! Thank you.

What does the modem status show ??? Page 23 in the user manual -- https://www.downloads.netgear.com/files/GDC/C7800/C7800_UM_EN.pdf

I would also factory reset the unit -- see page 111 in the above manual.

 

[drivinfast247]

Are you sure the coaxial cable that is connected to modem is receiving a signal from Comcast?

 

[ktrainhurricane]

What does the modem status show ??? Page 23 in the user manual -- https://www.downloads.netgear.com/files/GDC/C7800/C7800_UM_EN.pdf

I would also factory reset the unit -- see page 111 in the above manual.

Did the factory reset prior to calling Xfinity but it did not help.

To do the things on the router s login screen (page 23) I need to activate the modem with Xfinity, but that is not possible…or at least not something I’ve been able to do, despite trying.

 

[ktrainhurricane]

Are you sure the coaxial cable that is connected to modem is receiving a signal from Comcast?

How can I check / be sure?

(Sorry if that is a dumb question!)

 

[kanewolf]

How can I check / be sure?

(Sorry if that is a dumb question!)

I think the LEDs would be the place to look. See page 9 in the manual I linked. You need to have upstream and downstream channels locked.

Have you physically traced the coax with an ohm meter? Short the center conductor to the shield with a jumper wire and go to the Xfinitiy point-of-presence outside. Verify you have a short with a multi-meter. Also take a short coax and an extension cord. Connect the modem/router up outside near the Xfinity point-of-presence.

 

[ktrainhurricane]

Are you sure the coaxial cable that is connected to modem is receiving a signal from Comcast?

Yes. Xfinity tested the connection to the modem and said it is ok. I put back my old modem and it’s working.