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CM1200 - Lot of correctables and uncorrectables

New Poster

CM1200 - Lot of correctables and uncorrectables

I am connected to Internet using Netgear CM1200.

 

Info about Modem:

https://mydeviceinfo.xfinity.com/device/netgear-cm1200-702

 

I do get decent speed (But I feel that I don't get same level of speed as I need). If you see screenshot below - there is plenty of line noise. 

This was fixed initially (not sure how Comcast did it) - but now it is back.

 

 

 

 

comcast.png

I spoke to a customer service agent over phone and she suggested me to talk to netgear first.  

what is the best way to get this resolved?

Expert

Re: CM1200 - Lot of correctables and uncorrectables

Can't see your pic. Since you are a new poster, it needs to be approved by a Forum Admin. That could take some time. In the interim you could try hosting it at one of those free third-party pic hosting sites like Imgur or Photobucket and post the link to it here.



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New Poster

Re: CM1200 - Lot of correctables and uncorrectables

Here is the link to image of modem screen showing correctables. 

https://imgur.com/a/Z9rbHzS

New Poster

Re: CM1200 - Lot of correctables and uncorrectables

Thanks. Posted now.

Expert

Re: CM1200 - Lot of correctables and uncorrectables

O/k you didn't post the upstream power level figures. That being said, the downstream power is weak and it may be intermittently fluctuating even lower to out of spec levels. And the SNR is too low / out of spec on some of the channels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.



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New Poster

Re: CM1200 - Lot of correctables and uncorrectables

Okay - will go thru it again.

This was working fine for almost a year - no change to wiring since then.

 

Expert

Re: CM1200 - Lot of correctables and uncorrectables

Wiring / hardware conditions, connection quality can change all by itself. Good luck !



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New Poster

Re: CM1200 - Lot of correctables and uncorrectables

Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 34 441000000 Hz -6.3 dBmV 39.2 dB 42694 15487
2 Locked QAM256 1 471000000 Hz -5.3 dBmV 39.4 dB 24935 11999
3 Not Locked Unknown 2 477000000 Hz 0.0 dBmV 0.0 dB 0 0
4 Locked QAM256 3 483000000 Hz -6.7 dBmV 30 dB 1436475860 6084771
5 Locked QAM256 4 489000000 Hz -7.3 dBmV 38.6 dB 22978 7368
6 Locked QAM256 5 495000000 Hz -7.9 dBmV 31.7 dB 10203479 356245
7 Locked QAM256 6 507000000 Hz -8.3 dBmV 31.2 dB 306082321 21139146
8 Locked QAM256 7 513000000 Hz -7.3 dBmV 32.6 dB 1758750 16108
9 Locked QAM256 8 519000000 Hz -7.9 dBmV 36.4 dB 32848 8507
10 Locked QAM256 9 525000000 Hz -7.1 dBmV 33 dB 24163 7292
11 Locked QAM256 10 531000000 Hz -7.2 dBmV 35.7 dB 27761 7303
12 Locked QAM256 11 537000000 Hz -6.7 dBmV 31.4 dB 1591702 44046
13 Locked QAM256 12 543000000 Hz -7.1 dBmV 36.4 dB 22799 5426
14 Locked QAM256 13 555000000 Hz -6.9 dBmV 35.3 dB 20764 4390
15 Locked QAM256 14 561000000 Hz -8.1 dBmV 38.3 dB 22407 5506
16 Locked QAM256 15 567000000 Hz -7.3 dBmV 38.6 dB 17495 4320
17 Locked QAM256 16 573000000 Hz -7.8 dBmV 38.5 dB 22779 4200
18 Locked QAM256 17 579000000 Hz -7.1 dBmV 38.1 dB 15807 3577
19 Locked QAM256 18 585000000 Hz -7.5 dBmV 38.3 dB 20668 4030
20 Locked QAM256 19 591000000 Hz -7.1 dBmV 38.3 dB 15660 3559
21 Locked QAM256 20 597000000 Hz -7.3 dBmV 38.6 dB 17184 3851
22 Locked QAM256 21 603000000 Hz -7.8 dBmV 38.8 dB 17922 5109
23 Locked QAM256 22 609000000 Hz -7.9 dBmV 38.6 dB 18810 4764
24 Locked QAM256 23 615000000 Hz -9 dBmV 37.7 dB 22450 6575
25 Locked QAM256 24 621000000 Hz -8.5 dBmV 38 dB 91987248 17709891
26 Locked QAM256 25 627000000 Hz -9.5 dBmV 37.5 dB 39944 6653
27 Locked QAM256 26 633000000 Hz -9.4 dBmV 37.8 dB 20606 6635
28 Locked QAM256 27 639000000 Hz -9.3 dBmV 37.5 dB 25156 5321
29 Locked QAM256 35 453000000 Hz -5.8 dBmV 39.4 dB 41265 16609
30 Locked QAM256 36 459000000 Hz -4.7 dBmV 40.2 dB 37446 22896
31 Locked QAM256 37 465000000 Hz -5.2 dBmV 39.7 dB 29983 10985
32 Not Locked Unknown 0 0 Hz 0.0 dBmV 0.0 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 1 5120 Ksym/sec 35800000 Hz 52.5 dBmV
2 Locked ATDMA 2 5120 Ksym/sec 29400000 Hz 56.3 dBmV
3 Locked ATDMA 3 5120 Ksym/sec 23000000 Hz 53.5 dBmV
4 Locked ATDMA 4 5120 Ksym/sec 16600000 Hz 51.8 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
New Poster

Re: CM1200 - Lot of correctables and uncorrectables

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 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 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
 
Expert

Re: CM1200 - Lot of correctables and uncorrectables

O/k the upstream power is no good either.


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Official Employee

Re: CM1200 - Lot of correctables and uncorrectables

Hi there, chirag884. Sorry to see/hear about the trouble you're experiencing. We would like to look further into this for you. Please send us a private message with your name and we can continue from there. 

 

To send a private message, please click my name "Comcast Support" then select "Send a Message" on the right side.

 

Thank you!


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