Cable Modem High Error Status

[Danbar]

I have a Arris SB6190, with the following version: HW=3: SW =9.1.103AA65L. I have been intermittant very slow data downloads using Xfinity Speed Test. After resetting the modem (power-off) and  logging into the modems web view, there are no uncorrectable errors and the signal levels are between 4.9dBmv and 9.1dBmv and the download speed is as predicted (about 300-325mbps). After about a few hours, the speed deteriorates, there is about 35,000-72,000 uncorrfectable errors for each of 32 channels and the signal levels or some of the channels are -1.42dBmv. Is this a faulty modem or line or other?

Thanks

[EG]

It's more likely to be an intermittent line / signal / connection quality problem. Please also post the upstream power level and the SNR figures. Can you please post screenshots of all of the modems signal stat values both when they are good and not good .

[Danbar]

This is the best of could do. it shows a bad run. A good run is about the same, but with zero Corrected and Uncorrectables

Downstream Bonded Channels
Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Corrected	Uncorrectables
1	Locked	256QAM	15	585.00 MHz	5.00 dBmV	40.37 dB	174762	2827580
2	Locked	256QAM	1	495.00 MHz	4.20 dBmV	40.37 dB	159560	2737944
3	Locked	256QAM	2	501.00 MHz	3.80 dBmV	40.95 dB	161099	2743373
4	Locked	256QAM	3	507.00 MHz	3.60 dBmV	40.37 dB	160289	2731856
5	Locked	256QAM	4	513.00 MHz	3.60 dBmV	40.95 dB	162095	2717170
6	Locked	256QAM	5	519.00 MHz	3.60 dBmV	40.37 dB	163442	2806488
7	Locked	256QAM	6	525.00 MHz	3.70 dBmV	40.37 dB	160387	2724858
8	Locked	256QAM	7	531.00 MHz	3.80 dBmV	40.95 dB	157822	2731051
9	Locked	256QAM	8	537.00 MHz	4.00 dBmV	40.37 dB	160296	2723474
10	Locked	256QAM	9	543.00 MHz	4.30 dBmV	40.95 dB	168587	2726577
11	Locked	256QAM	10	549.00 MHz	4.90 dBmV	40.95 dB	175691	2670215
12	Locked	256QAM	11	561.00 MHz	5.90 dBmV	40.37 dB	185060	2774767
13	Locked	256QAM	12	567.00 MHz	6.50 dBmV	40.95 dB	164570	2831644
14	Locked	256QAM	13	573.00 MHz	6.20 dBmV	40.37 dB	158664	2849305
15	Locked	256QAM	14	579.00 MHz	6.10 dBmV	40.95 dB	160531	2845473
16	Locked	256QAM	16	591.00 MHz	4.60 dBmV	40.37 dB	181750	2806593
17	Locked	256QAM	17	597.00 MHz	3.60 dBmV	40.95 dB	178067	2770145
18	Locked	256QAM	18	603.00 MHz	3.20 dBmV	40.37 dB	165455	2763651
19	Locked	256QAM	19	609.00 MHz	2.40 dBmV	38.98 dB	160694	2742866
20	Locked	256QAM	20	615.00 MHz	2.60 dBmV	40.37 dB	159309	2740193
21	Locked	256QAM	21	621.00 MHz	2.30 dBmV	40.37 dB	170111	2761485
22	Locked	256QAM	22	627.00 MHz	3.40 dBmV	40.37 dB	185064	2849094
23	Locked	256QAM	23	633.00 MHz	4.30 dBmV	38.98 dB	228752	2867569
24	Locked	256QAM	24	639.00 MHz	8.40 dBmV	38.61 dB	250534	3460560
25	Locked	256QAM	26	645.00 MHz	11.20 dBmV	38.90 dB	1077576	112933
26	Locked	256QAM	27	651.00 MHz	7.40 dBmV	35.90 dB	2038638	265255
27	Locked	256QAM	28	657.00 MHz	2.60 dBmV	38.90 dB	8521	16208
28	Locked	256QAM	29	663.00 MHz	1.10 dBmV	38.60 dB	1677	15045
29	Locked	256QAM	30	669.00 MHz	1.40 dBmV	38.90 dB	1214	10840
30	Locked	256QAM	31	675.00 MHz	-1.30 dBmV	36.90 dB	37701	19618
31	Locked	256QAM	32	681.00 MHz	-0.50 dBmV	37.60 dB	1913	12141
32	Locked	256QAM	33	687.00 MHz	0.90 dBmV	38.90 dB	1357	11686

Upstream Bonded Channels
Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	2	5120 kSym/s	30.10 MHz	39.00 dBmV
2	Locked	ATDMA	4	5120 kSym/s	17.30 MHz	38.75 dBmV
3	Locked	ATDMA	3	5120 kSym/s	23.70 MHz	38.75 dBmV
4	Locked	ATDMA	1	5120 kSym/s	36.50 MHz	39.00 dBmV

[Danbar]

also a good run does not have low power. They range from 4.8 to 9.10dBmV

[EG]

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@Danbar wrote:

also a good run does not have low power. They range from 4.8 to 9.10dBmV

---

What about the upstream stats on a good and a bad "run" ?

[Danbar]

The good and bad upstream are identical: power levels for a good are all 38.75. As seen above, a bad run dips to 38.75

Thanks again

[EG]

Alright well something is going on as there is a very wide variation with the downstream power levels of the channels ! Should be no more than a 3-4 dB variation. See if anything here helps / applies;

In a self troubleshooting effort to try to obtain better connectivity, 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.

[Danbar]

You are so helpful and I am most appreciative!!! The following is my configuration:

1. The cable from the street is connected to a barrier connector with a ground. Just straight through....

2. From the barrier connector, the cable goes to a 1 to 3 splitter of the following characteristics:

2.1. "Extreme Broadband Engineering" model BDS103HB; 3-way balanced Digital Splitter

2.2 Each leg is marked "Out -5.5db"

2.3 One leg goes to the cable modem

2.4 The second leg goes directly to the X1 DVR

2.5 The third leg goes to a multi-leg splitter for subsequent connection to 5 DTA's and to the voice modem.

[EG]

Have you tried refreshing / checking / cleaning / tightening any of the connections leading to the modem ?

[Danbar]

Everything is brand spanking new. Called Customer service and did observed  some aberrations on their end.  So I scheduled a technican to take a look at things. 

Thanks again, you have been so helpful!!

[EG]

That was going to be my next suggestion. Good luck with it ! Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.

Please post back with how things turn out.

[Danbar]

A technician checked the signal level and my splitter configuration. He forced a refresh to the modem, ensuring the modem properly received a complete configuration/firmware refresh. He then removed my old amplifier for the DTA and old splitters and replaced them with a completely new configuration/ equipment. Padded down the input signal down a bit and checked the signals across the frequency spectrum with an analyzer. Also, he reterminated all my connections. I now have been running with zero "uncorrectables", 360mbps download speeds. The technician did a great job! And I thank you for your help in the diagnoses. 

[EG]

Quite welcome ! Hope things hold up for you !