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SB6190 high uncorrectable errors on single channel

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New Poster

SB6190 high uncorrectable errors on single channel

I just upgraded my service from the legacy Blast Tier to Blast! Pro. As part of that, I replaced my SB6121 with a new SB6190. I used to get very consistent 120/12 speeds with the SB6121. Now that I've replaced the modem I'm getting download speeds varying from 45 to as high as 295 Mbps (tested against Comcast's speed test server in Denver). Uploads seem steady at 12 - 15 Mbps. The big issue is that the download speeds are now completely inconsistent and page loads feel substantially slower.

 

I have included the details from my modem's status and error pages below. It seems pretty clear that there is an issue with the 549 Mhz channel. We do not have tv and there are no splitters between the pole and our house. I've checked all cable connections that I can access and they are all tight.

 

Any thoughts on resolving this? Can Xfinity just not assign my modem channel 9? Would switching to a 6183 with fewer channels resolve this?

 

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked 256QAM 31 687.00 MHz -1.30 dBmV 38.98 dB 0 0
2 Not Locked ---- 1 507.00 MHz ---- ---- ---- ----
3 Not Locked ---- 2 513.00 MHz ---- ---- ---- ----
4 Not Locked ---- 3 519.00 MHz ---- ---- ---- ----
5 Not Locked ---- 4 525.00 MHz ---- ---- ---- ----
6 Not Locked ---- 5 531.00 MHz ---- ---- ---- ----
7 Not Locked ---- 6 537.00 MHz ---- ---- ---- ----
8 Not Locked ---- 7 543.00 MHz ---- ---- ---- ----
9 Locked 256QAM 8 549.00 MHz -14.10 dBmV 31.40 dB 63535814 18986611
10 Locked 256QAM 9 555.00 MHz -6.70 dBmV 37.64 dB 7 0
11 Locked 256QAM 10 561.00 MHz -5.00 dBmV 38.61 dB 16 0
12 Locked 256QAM 11 567.00 MHz -3.30 dBmV 38.98 dB 7 0
13 Locked 256QAM 12 573.00 MHz -1.70 dBmV 38.98 dB 0 0
14 Locked 256QAM 13 579.00 MHz -0.60 dBmV 38.98 dB 20 0
15 Locked 256QAM 14 585.00 MHz 0.10 dBmV 40.37 dB 0 0
16 Locked 256QAM 15 591.00 MHz 0.50 dBmV 40.37 dB 0 0
17 Locked 256QAM 16 597.00 MHz 0.50 dBmV 40.95 dB 4 0
18 Locked 256QAM 17 603.00 MHz 0.50 dBmV 40.37 dB 7 0
19 Locked 256QAM 18 609.00 MHz 0.50 dBmV 40.37 dB 4 0
20 Locked 256QAM 19 615.00 MHz 0.30 dBmV 40.37 dB 3 0
21 Locked 256QAM 20 621.00 MHz 0.00 dBmV 40.37 dB 0 0
22 Locked 256QAM 21 627.00 MHz -0.30 dBmV 38.98 dB 0 0
23 Locked 256QAM 22 633.00 MHz -0.30 dBmV 40.37 dB 5 0
24 Locked 256QAM 23 639.00 MHz -0.40 dBmV 38.98 dB 2 0
25 Locked 256QAM 24 645.00 MHz -0.50 dBmV 39.90 dB 5 0
26 Locked 256QAM 25 651.00 MHz -0.80 dBmV 39.50 dB 4 0
27 Locked 256QAM 26 657.00 MHz -0.90 dBmV 39.20 dB 0 0
28 Locked 256QAM 27 663.00 MHz -1.10 dBmV 39.50 dB 0 0
29 Locked 256QAM 28 669.00 MHz -1.40 dBmV 39.20 dB 0 0
30 Locked 256QAM 29 675.00 MHz -1.80 dBmV 38.90 dB 0 0
31 Locked 256QAM 30 681.00 MHz -1.50 dBmV 39.50 dB 0 0
 
Upstream Bonded Channels
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 17 5120 kSym/s 36.50 MHz 42.50 dBmV
2 Locked ATDMA 20 5120 kSym/s 17.30 MHz 40.75 dBmV
3 Locked ATDMA 19 5120 kSym/s 23.70 MHz 41.00 dBmV
4 Locked ATDMA 18 5120 kSym/s 30.10 MHz 41.75 dBmV
 

Current System Time: Sat Jan 13 18:11:35 2018

 

Sat Jan 13 17:39:09 2018 5 Lost MDD Timeout;CM-MAC=XX;CMTS-MAC=00:01:5c:66:04:4a;CM-QOS=1.1;CM-VER=3.0;
Sat Jan 13 17:39:20 2018 5 RCS Partial Service;CM-MAC=XX;CMTS-MAC=00:01:5c:66:04:4a;CM-QOS=1.1;CM-VER=3.0;
Sat Jan 13 17:41:54 2018 5 Lost MDD Timeout;CM-MAC=XX;CMTS-MAC=00:01:5c:66:04:4a;CM-QOS=1.1;CM-VER=3.0;
Sat Jan 13 17:41:59 2018 5 RCS Partial Service;CM-MAC=XX;CMTS-MAC=00:01:5c:66:04:4a;CM-QOS=1.1;CM-VER=3.0;

* I've blanked my modem's MAC address for privacy reasons.

New Poster

Re: SB6190 high uncorrectable errors on single channel

I just finished chatting with Xfinity support. He had me plug directly into the modem, which made no difference. He also re-provisioned the modem, but again no impact. I'm still seeing the same high level of uncorrectable errors as shown in my previous post. In the end the CSR scheduled a technician to come on monday to diagnose the issue "between the pole and the modem" since I'm still experiencing packet loss (his words).

 

A thought occurred to me -- should all 32 channels be locked? It seems curious that the power hovers around +/- 1dB for the higher frequency channels, but starting with 573 Mhz down to 549 Mhz, the Power drops off rapidly. Are the lower frequency channels not locked because the power is outside of the -15dB minimum? Could this be indicative of some kind of trap/filter on the line at the pole? A high pass filter of 550+ would certainly manifest as a signal drop in the lower frequencies like I'm seeing. AFAICT it's just a long coax run between the pole and the modem with two union connectors at the demarc point. I'm sure the technician will find the issue on Monday, but I'd love to be able to help point them in the right direction when they get here.

New Poster

Re: SB6190 high uncorrectable errors on single channel

The technician just left and everything looks great now. There was indeed a filter up on the pole which he removed and he decided to run a fresh cable from the pole to house as well. We're now locked to 31 channels with no uncorrectable errors.

 

Downstream Bonded Channels
Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected Uncorrectables
1 Locked 256QAM 31 687.00 MHz 4.50 dBmV 38.98 dB 6 0
2 Locked 256QAM 1 507.00 MHz 4.60 dBmV 38.98 dB 6 0
3 Locked 256QAM 2 513.00 MHz 4.90 dBmV 38.98 dB 0 0
4 Locked 256QAM 3 519.00 MHz 5.00 dBmV 38.98 dB 0 0
5 Locked 256QAM 4 525.00 MHz 5.20 dBmV 38.61 dB 0 0
6 Locked 256QAM 5 531.00 MHz 5.40 dBmV 38.98 dB 11 0
7 Locked 256QAM 6 537.00 MHz 5.60 dBmV 38.98 dB 13 0
8 Locked 256QAM 7 543.00 MHz 6.10 dBmV 40.37 dB 8 0
9 Locked 256QAM 8 549.00 MHz 6.10 dBmV 38.98 dB 0 0
10 Locked 256QAM 9 555.00 MHz 6.40 dBmV 40.37 dB 0 0
11 Locked 256QAM 10 561.00 MHz 6.50 dBmV 38.98 dB 0 0
12 Locked 256QAM 11 567.00 MHz 6.60 dBmV 40.37 dB 0 0
13 Locked 256QAM 12 573.00 MHz 6.70 dBmV 38.98 dB 0 0
14 Locked 256QAM 13 579.00 MHz 6.90 dBmV 38.98 dB 0 0
15 Locked 256QAM 14 585.00 MHz 7.10 dBmV 40.37 dB 16 0
16 Locked 256QAM 15 591.00 MHz 7.40 dBmV 40.37 dB 10 0
17 Locked 256QAM 16 597.00 MHz 7.30 dBmV 40.37 dB 15 0
18 Locked 256QAM 17 603.00 MHz 7.20 dBmV 40.37 dB 5 0
19 Locked 256QAM 18 609.00 MHz 7.30 dBmV 40.37 dB 15 0
20 Locked 256QAM 19 615.00 MHz 7.10 dBmV 40.37 dB 0 0
21 Locked 256QAM 20 621.00 MHz 6.90 dBmV 40.37 dB 0 0
22 Locked 256QAM 21 627.00 MHz 6.60 dBmV 38.98 dB 0 0
23 Locked 256QAM 22 633.00 MHz 6.40 dBmV 38.98 dB 4 0
24 Locked 256QAM 23 639.00 MHz 6.30 dBmV 38.98 dB 6 0
25 Locked 256QAM 24 645.00 MHz 6.20 dBmV 39.50 dB 0 0
26 Locked 256QAM 25 651.00 MHz 5.80 dBmV 39.20 dB 3 0
27 Locked 256QAM 26 657.00 MHz 5.60 dBmV 38.90 dB 0 0
28 Locked 256QAM 27 663.00 MHz 5.40 dBmV 38.90 dB 0 0
29 Locked 256QAM 28 669.00 MHz 5.30 dBmV 39.20 dB 0 0
30 Locked 256QAM 29 675.00 MHz 4.80 dBmV 38.60 dB 0 0
31 Locked 256QAM 30 681.00 MHz 4.40 dBmV 38.90 dB 0 0
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