Skip to main content

    Support

    Offers

T
thx_1138
1st Topic
1st Reply
1st Like

Visitor

 • 

19 Messages

Wednesday, June 16th, 2021 6:01 PM

Closed

Nighthawk CM2000 - no 1.2Gbs speed.. barely 900Mbit speed and Cable Modems keep burning out

Hi,

I have upgraded to a Netgear Nighthawk CM2000 router from an Arris SB8200. I have run into multiple problems over the last few months and I need help..

- No speeds above 900Mbp/s are available, regardless of how I connect to the cable modem

- Both the SB8200 and the CM2000 stay in "scanning" mode for a downstream channel. 

- I have frequent drops in my internet access

- I have had THREE modems in the last 6 months burn out and stop working.. They refuse to boot on a power cycle, and tech support for the modems has me ship them back for replacement - this has happened regardless of make/model (1 Arris and two different models of Netgear.. 2 CM2000's have burned out and 1 CM1000 has).

- Talking to tech support has been useless... they will not get a repair ticket opened to have Xfinity come here to check my cable or service.

- Trying to ask for someone in a US call center gets me hung up on by your outsourced call center in the philippines... 

I need to get this resolved.. what is it going to take...?

Question

 • 

Updated 

4 years ago

1.5K

2

0

thx_1138

Visitor

 • 

19 Messages

4 years ago

I have pulled the cable connection stats off the modem. Here is the stats for 4 days of update.  The correctable and uncorrectable error rates seem way too high for channels 28 thru 31...  I really need someone to respond from Comcast tech support. The modem is the ONLY connection going out to the cable outside.

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 37 651000000 Hz -6.6 dBmV 34.6 dB 35 0
2 Locked QAM256 13 495000000 Hz -5.1 dBmV 35.0 dB 0 0
3 Locked QAM256 14 507000000 Hz -5.7 dBmV 35.0 dB 0 0
4 Locked QAM256 15 513000000 Hz -6.3 dBmV 35.0 dB 0 0
5 Locked QAM256 16 519000000 Hz -6.5 dBmV 35.0 dB 1 0
6 Locked QAM256 17 525000000 Hz -6.5 dBmV 34.9 dB 0 0
7 Locked QAM256 18 531000000 Hz -6.6 dBmV 34.8 dB 0 0
8 Locked QAM256 19 543000000 Hz -6.5 dBmV 34.9 dB 1 0
9 Locked QAM256 20 549000000 Hz -6.7 dBmV 34.8 dB 2 0
10 Locked QAM256 21 555000000 Hz -7.0 dBmV 34.7 dB 2 0
11 Locked QAM256 22 561000000 Hz -7.0 dBmV 34.8 dB 1 0
12 Locked QAM256 23 567000000 Hz -6.6 dBmV 34.9 dB 2 0
13 Locked QAM256 24 573000000 Hz -7.0 dBmV 34.8 dB 1 0
14 Locked QAM256 25 579000000 Hz -6.7 dBmV 34.9 dB 6 0
15 Locked QAM256 26 585000000 Hz -6.7 dBmV 34.7 dB 3 0
16 Locked QAM256 27 591000000 Hz -7.1 dBmV 34.8 dB 3 0
17 Locked QAM256 28 597000000 Hz -7.5 dBmV 34.7 dB 2 0
18 Locked QAM256 29 603000000 Hz -7.7 dBmV 34.6 dB 0 0
19 Locked QAM256 30 609000000 Hz -7.6 dBmV 34.6 dB 1 0
20 Locked QAM256 31 615000000 Hz -7.4 dBmV 34.7 dB 2 0
21 Locked QAM256 32 621000000 Hz -6.9 dBmV 34.5 dB 2 0
22 Locked QAM256 33 627000000 Hz -6.8 dBmV 34.1 dB 15 0
23 Locked QAM256 34 633000000 Hz -7.0 dBmV 34.0 dB 35 0
24 Locked QAM256 35 639000000 Hz -6.5 dBmV 34.0 dB 958 0
25 Locked QAM256 36 645000000 Hz -6.7 dBmV 34.6 dB 19 0
26 Locked QAM256 38 657000000 Hz -6.2 dBmV 34.8 dB 28 0
27 Locked QAM256 39 663000000 Hz -6.2 dBmV 34.6 dB 11 0
28 Locked QAM256 40 669000000 Hz -6.6 dBmV 34.6 dB 482318 996336
29 Locked QAM256 41 675000000 Hz -6.8 dBmV 34.4 dB 809393 2372329
30 Locked QAM256 42 681000000 Hz -6.9 dBmV 34.6 dB 1064610 3746604
31 Locked QAM256 43 687000000 Hz -6.8 dBmV 34.7 dB 153019 286373
32 Locked QAM256 44 693000000 Hz -6.4 dBmV 34.7 dB 12 0

7

0

user_Kaitlan

Contributor

 • 

317 Messages

Hello, @thx_1138! I'm sorry to hear about any delays in getting assistance with this connection issue. The SB8200 is actually not compatible with our firmware after our increase from 1.0 to 1.2 Gbps; we are aware that this is a popular model, though, and I assure you that we're looking into it to see what we need to adjust so this model can continue to be used. We do know that it's capable of handling those speeds, this is more about the actual firmware than anything.

 

As for the other model, I do want to run a few tests and see what's going on to also check that connection. May I please have you send me a Message with the full name of the Account Owner and yourself, if different, as well as the full address on file?

 

To send a Message:
1. Click on the Chat Bubble icon in the upper right corner to access our new Peer 2 Peer feature!
2. Search for "Xfinity Support" and select "Xfinity Support" from the drop down list.
3. Type your message in the text area.
4. Press Enter to send!

4 years ago

0

EG

Expert

 • 

111.1K Messages

@thx_1138

The downstream power is low / weak and the SNR's are also low / out of spec. Please also post the upstream power level figures. 

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

4 years ago

0

thx_1138

Visitor

 • 

19 Messages

@ComcastKaitlan  "The SB8200 is actually not compatible with our firmware after our increase from 1.0 to 1.2 Gbps; we are aware that this is a popular model,"

Right which is why I upgraded to the CM2000...

(edited)

4 years ago

0

thx_1138

Visitor

 • 

19 Messages

@EG  Here's the latest upstream power level figures... What do I need to do, whom do I call to get this looked into?

Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 16400000 Hz 44.5 dBmV
2 Locked ATDMA 2 5120 22800000 Hz 44.5 dBmV
3 Locked ATDMA 3 5120 29200000 Hz 45.0 dBmV
4 Locked ATDMA 4 5120 35600000 Hz 45.0 dBmV
5 Locked ATDMA 5 2560 40400000 Hz 46.5 dBmV
6 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 0 Hz 0.0 dBmV

4 years ago

0

thx_1138

Visitor

 • 

19 Messages

@ComcastKaitlan  Message sent as per you instructions to Xfinity support with a link back to this thread. Hopefully I hear something soon. Thanks.

4 years ago

0

thx_1138

Visitor

 • 

19 Messages

4 years ago

@ComcastKaitlan - Tech came to my residence today. Found that everything up to the port for the cable modem for signal blocks and connectors (with the exception of the coax) needed replacement. Those were all from when Cable internet was first put on the house by Comcast/XFinity Once that was done everything is working much better... correctable errors on downstream channels have dropped to zero... and the signal levels look better too.. Thank you @EG for your assistance and insights as well.

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 423000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
 
Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 1 423000000 Hz -5.4 dBmV 36.9 dB 0 0
2 Locked QAM256 2 429000000 Hz -5.3 dBmV 37.0 dB 0 0
3 Locked QAM256 3 435000000 Hz -5.2 dBmV 36.9 dB 0 0
4 Locked QAM256 4 441000000 Hz -5.1 dBmV 36.9 dB 0 0
5 Locked QAM256 5 447000000 Hz -4.9 dBmV 36.9 dB 0 0
6 Locked QAM256 6 453000000 Hz -4.9 dBmV 37.0 dB 0 0
7 Locked QAM256 7 459000000 Hz -5.3 dBmV 36.9 dB 0 0
8 Locked QAM256 8 465000000 Hz -5.6 dBmV 36.9 dB 0 0
9 Locked QAM256 9 471000000 Hz -5.7 dBmV 36.8 dB 0 0
10 Locked QAM256 10 477000000 Hz -5.6 dBmV 36.8 dB 0 0
11 Locked QAM256 11 483000000 Hz -5.5 dBmV 36.8 dB 0 0
12 Locked QAM256 12 489000000 Hz -5.4 dBmV 36.8 dB 0 0
13 Locked QAM256 13 495000000 Hz -5.5 dBmV 36.7 dB 0 0
14 Locked QAM256 14 507000000 Hz -6.2 dBmV 36.5 dB 0 0
15 Locked QAM256 15 513000000 Hz -6.7 dBmV 36.5 dB 0 0
16 Locked QAM256 16 519000000 Hz -6.9 dBmV 36.5 dB 0 0
17 Locked QAM256 17 525000000 Hz -6.9 dBmV 36.4 dB 0 0
18 Locked QAM256 18 531000000 Hz -6.9 dBmV 36.3 dB 0 0
19 Locked QAM256 19 543000000 Hz -7.0 dBmV 36.4 dB 0 0
20 Locked QAM256 20 549000000 Hz -7.2 dBmV 36.3 dB 0 0
21 Locked QAM256 21 555000000 Hz -7.4 dBmV 36.2 dB 0 0
22 Locked QAM256 22 561000000 Hz -7.4 dBmV 36.2 dB 0 0
23 Locked QAM256 23 567000000 Hz -7.1 dBmV 36.3 dB 0 0
24 Locked QAM256 24 573000000 Hz -7.2 dBmV 36.3 dB 0 0
25 Locked QAM256 25 579000000 Hz -7.1 dBmV 36.3 dB 0 0
26 Locked QAM256 26 585000000 Hz -7.3 dBmV 36.1 dB 0 0
27 Locked QAM256 27 591000000 Hz -7.5 dBmV 36.2 dB 0 0
28 Locked QAM256 28 597000000 Hz -8.0 dBmV 36.1 dB 0 0
29 Locked QAM256 29 603000000 Hz -8.1 dBmV 36.0 dB 0 0
30 Locked QAM256 30 609000000 Hz -7.9 dBmV 36.0 dB 0 0
31 Locked QAM256 31 615000000 Hz -7.7 dBmV 36.1 dB 0 0
32 Locked QAM256 32 621000000 Hz -7.5 dBmV 35.9 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 16400000 Hz 45.5 dBmV
2 Locked ATDMA 2 5120 22800000 Hz 46.0 dBmV
3 Locked ATDMA 3 5120 29200000 Hz 46.0 dBmV
4 Locked ATDMA 4 5120 35600000 Hz 46.5 dBmV
5 Locked ATDMA 5 2560 40400000 Hz 48.0 dBmV
6 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 0 Hz 0.0 dBmV
 
Downstream OFDM Channels
Channel Lock
Status		 Modulation /
Profile ID		 Channel
ID		 Frequency Power SNR /
MER		 Active Subcarrier
Number Range		 Unerrored
Codewords		 Correctable
Codewords		 Uncorrectable
Codewords
1 Locked 0 159 722000000 Hz -6.5 dBmV 36.2 dB 1246 ~ 2849 127434979 693810 0
2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0
 
Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV

6

XfinityRyanE

Official Employee

 • 

1.1K Messages

Thank you for the update @thx_1138. We want to thank you for reaching out to the Community Forum for support with your connection issue. We are glad we were able to resolve your issue. Never hesitate to create another public post for any of your future account and service needs! 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

4 years ago

0

EG

Expert

 • 

111.1K Messages

@thx_1138

The downstream power is still on the weak side... The SNR is a tad better. More work needs to be done.. The hotter that the temperatures get this Summer, the worse the signals become ! If the problem returns, get the techs involved again. Hope things hold up for you. Good Luck !! 

(edited)

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

4 years ago

EG

Expert

 • 

111.1K Messages

Perhaps we shouldn't celebrate quite yet. 

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

4 years ago

0

thx_1138

Visitor

 • 

19 Messages

@EG thanks for the tidbit.. I'll see how things go and how overall signal strength looks over the next couple of weeks.  

4 years ago

EG

Expert

 • 

111.1K Messages

My pleasure ! Please post back with an update.

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

4 years ago

0

forum icon

New to the Community?

Start Here