Motorola MB8611 reporting huge amounts of Corrected and Uncorrected Errors & Speed Flucations

Recently upgraded my home connection speed to the 900/20 plan. When I made the switch I was informed to upgrade my cable modem from my older model to be compatible with the new speed.

Now my connection is unstable. The speed will fluctuate wildly throughout the day seemingly at random. It will drop as low as 15-45 down, then within 3-5 minutes be back to 600+ down. (Tests run through independent speed test sites using a wired connection).

Restarting the modem (either manually or through the Xfinity website) seems to do nothing.

Here are the current connection stats since the last restart. Modem has only been up and running for 15 hours. (Event log is also filled with notices and warnings).

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Freq. (MHz)	Pwr (dBmV)	SNR (dB)	Corrected	Uncorrected
1	Locked	QAM256	5	543.0	-6.9	39.2	154	85
2	Locked	QAM256	2	525.0	-5.6	41.4	41	11
3	Locked	QAM256	3	531.0	-7.5	40.3	249	83
4	Locked	QAM256	4	537.0	-4.9	37.9	41	28
5	Locked	QAM256	6	555.0	-4.1	31.1	159268030	422859
6	Locked	QAM256	7	561.0	-6.4	27.7	495878760	20688252
7	Locked	QAM256	8	567.0	-4.0	34.2	16	0
8	Locked	QAM256	9	573.0	-5.8	30.7	48268	4312
9	Locked	QAM256	10	579.0	-5.6	39.3	5	0
10	Locked	QAM256	11	585.0	-6.2	40.6	65	26
11	Locked	QAM256	12	591.0	-6.9	40.3	167	102
12	Locked	QAM256	13	597.0	-5.5	33.1	819	26
13	Locked	QAM256	14	603.0	-7.5	27.0	2760931	2804352
14	Locked	QAM256	15	609.0	-5.7	37.9	2980	1962
15	Locked	QAM256	16	615.0	-6.4	40.8	33	4
16	Locked	QAM256	17	621.0	-6.2	40.1	43	7
17	Locked	QAM256	18	627.0	-6.3	38.3	36	1
18	Locked	QAM256	19	633.0	-7.4	39.6	11	0
19	Locked	QAM256	20	639.0	-5.8	40.1	0	0
20	Locked	QAM256	21	645.0	-8.2	39.5	329	94
21	Locked	QAM256	22	651.0	-7.3	40.1	49	0
22	Locked	QAM256	23	657.0	-6.8	40.5	12	0
23	Locked	QAM256	24	663.0	-8.1	39.7	68	92
24	Locked	QAM256	25	669.0	-5.4	41.2	0	0
25	Locked	QAM256	26	675.0	-6.8	39.7	2	0
26	Locked	QAM256	27	681.0	-5.2	41.5	30	1
27	Locked	QAM256	28	687.0	-7.0	40.5	85	42
28	Locked	QAM256	29	693.0	-6.9	40.5	47	25
29	Locked	QAM256	30	699.0	-6.2	41.0	35	48
30	Locked	QAM256	31	705.0	-8.5	39.6	3756	8585
31	Locked	QAM256	32	711.0	-7.9	40.0	4147	6380
32	Locked	OFDM PLC	37	762.0	-8.3	37.0	384425736	57042

Upstream Bonded Channels

Channel	Lock Status	Channel Type	Channel ID	Symb. Rate (Ksym/sec)	Freq. (MHz)	Pwr (dBmV)
1	Locked	SC-QAM	9	5120	35.6	47.3
2	Locked	SC-QAM	10	5120	29.2	53.5
3	Locked	SC-QAM	11	5120	22.8	51.8
4	Locked	SC-QAM	12	5120	16.4	50.5

Event log warnings all read

13:19:22
Tue Jan 25 2022

Warning (5)

MDD message timeout

Responses

EG

Expert

•

111.3K Messages

3 years ago

The upstream power is too high (already out of spec on channel #2) and it may be intermittently fluctuating even higher out of spec. And the downstream power is on the low weak side. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.

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.

Good luck with it !

3

U

user_d11a2b

Visitor

•

3 Messages

@EG Moved the router to be directly on the line coming from outside the house (so no splitters, no splice).

Only been running for 5 minutes and already loads of corrected and uncorrected.

Connection Status

System Up Time	0 days 00h:05m:30s
Network Access	Allowed

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Freq. (MHz)	Pwr (dBmV)	SNR (dB)	Corrected	Uncorrected
1	Locked	QAM256	5	543.0	-3.5	39.9	13	0
2	Locked	QAM256	1	519.0	-5.1	40.9	32	0
3	Locked	QAM256	2	525.0	-2.0	42.3	5	0
4	Locked	QAM256	3	531.0	-4.6	41.3	37	6
5	Locked	QAM256	4	537.0	-2.3	38.6	6	0
6	Locked	QAM256	6	555.0	-0.7	31.0	17155	0
7	Locked	QAM256	7	561.0	-3.1	29.6	15099	11
8	Locked	QAM256	8	567.0	-1.2	36.5	33	0
9	Locked	QAM256	9	573.0	-2.2	32.6	31	0
10	Locked	QAM256	10	579.0	-2.6	40.4	32	0
11	Locked	QAM256	11	585.0	-3.0	41.7	31	0
12	Locked	QAM256	12	591.0	-3.3	41.5	0	0
13	Locked	QAM256	13	597.0	-2.7	32.1	0	0
14	Locked	Unknown	14	603.0	-3.8	0.0	173	0
15	Locked	QAM256	15	609.0	-2.6	38.8	12	0
16	Locked	QAM256	16	615.0	-3.2	41.8	0	0
17	Locked	QAM256	17	621.0	-2.7	41.0	0	0
18	Locked	QAM256	18	627.0	-3.5	39.6	0	0
19	Locked	QAM256	19	633.0	-3.9	41.2	0	0
20	Locked	QAM256	33	495.0	-1.7	42.5	28	16
21	Locked	QAM256	34	501.0	-6.0	40.5	33	7
22	Locked	QAM256	35	507.0	-2.6	42.3	33	0
23	Locked	QAM256	36	513.0	-3.4	41.6	30	14
24	Locked	OFDM PLC	37	762.0	-5.3	37.5	1828812	327
25	Locked	QAM256	38	471.0	-5.2	41.1	36	0
26	Locked	QAM256	39	477.0	-3.4	41.9	33	10
27	Locked	QAM256	40	483.0	-4.0	40.5	28	17
28	Locked	QAM256	41	489.0	-5.5	40.9	28	17
29	Locked	QAM256	42	447.0	-0.7	42.9	0	0
30	Locked	QAM256	43	453.0	-1.5	42.3	4	0
31	Locked	QAM256	44	459.0	-3.5	41.7	31	12
32	Locked	QAM256	45	465.0	-1.3	41.9	24	0

Upstream Bonded Channels

Channel	Lock Status	Channel Type	Channel ID	Symb. Rate (Ksym/sec)	Freq. (MHz)	Pwr (dBmV)
1	Locked	SC-QAM	9	5120	35.6	46.3
2	Locked	SC-QAM	10	5120	29.2	52.5
3	Locked	SC-QAM	11	5120	22.8	51.3
4	Locked	SC-QAM	12	5120	16.4	49.3

Downstream Frequency Setting

Downstream Frequency Select

3 years ago

0

EG

Expert

•

111.3K Messages

It's still too high. If there is nothing more that can be done to improve the connection, you may want to consider getting a tech out to investigate / correct.

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.

Good luck !

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.

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3 years ago

U

user_d11a2b

Visitor

•

3 Messages

Looks like I'll need a tech out. Probably need to wait for the snow to melt.

3 years ago

0

EG

Expert

•

111.3K Messages

3 years ago

Please post back with how things turn out.

0

sbujak1

Regular Visitor

•

7 Messages

3 years ago

Modem: Motorola MB861. Service 900 MBS everything looks good, except Ch. 32 has a large number of corrected errors. see attached images. All connections were checked and cleaned with good quality, contact cleaner/degreaser except up on the pole. My speed is fine. 800-900+ MBS can someone command on CH32 errors. Best Regards

0

EG

Expert

•

111.3K Messages

3 years ago

@sbujak1

Please create a new topic of your own here on this board detailing your issue. Thanks. The original poster has not returned. 6-month-old dead thread is now being closed.

0

Your Home Network

user_d11a2b

Motorola MB8611 reporting huge amounts of Corrected and Uncorrected Errors & Speed Flucations

EG

user_d11a2b

EG

user_d11a2b

EG

sbujak1

EG

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