Motorola MB8611 Constantly Loses Signal

I recently upgraded my modem to a Motorola MB8611 and since then I've had constant internet connectivity issues. My modem is constantly losing connection causing it to reboot (5-6 times per hour). Reading other posts on here it seems like others have had this same issue. I have no splitters on my coax cable and have replaced the cable to make sure it wasn't the issue. Recent log from the modem is below. What do I need to do to correct this issue?

Event Log

Time	Priority	Description
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=0;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=:;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=\CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Critical (3)	No Ranging Response received - T3 time-out;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
Time Not Established	Notice (6)	Honoring MDD; IP provisioning mode = IPv6
12:48:31 Fri Jul 1 2022	Notice (6)	DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;
12:48:44 Fri Jul 1 2022	Notice (6)	CM-STATUS message sent. Event Type Code: 24; Chan ID: 48; DSID: N/A; MAC Addr: N/A; OFDM/OFDMA Profile ID: 0.;CM-MAC=;CMTS-MAC=;CM-QOS=1.1;CM-VER=3.1;

This conversation is no longer open for comments or replies and is no longer visible to community members.

Responses

Oldest First

Selected Oldest First

EG

Expert

•

118.3K Messages

4 years ago

Please also copy all of the text in its entirety of the *Downstream Power Levels*, the *SNR's* (Signal to Noise Ratios), and the *Upstream Power Level* numbers and paste them into your next post.

0

U

user_447f6c

Visitor

•

2 Messages

4 years ago

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Freq. (MHz)	Pwr (dBmV)	SNR (dB)	Corrected	Uncorrected
1	Locked	QAM256	32	597.0	1.4	43.5	0	0
2	Locked	QAM256	17	507.0	1.2	43.5	0	0
3	Locked	QAM256	18	513.0	1.1	43.5	0	0
4	Locked	QAM256	19	519.0	1.2	43.5	0	0
5	Locked	QAM256	20	525.0	1.1	43.5	0	0
6	Locked	QAM256	21	531.0	1.2	43.5	0	0
7	Locked	QAM256	22	537.0	1.1	43.7	1	0
8	Locked	QAM256	23	543.0	1.1	43.5	0	0
9	Locked	QAM256	24	549.0	1.0	43.3	0	0
10	Locked	QAM256	25	555.0	1.0	43.5	1	0
11	Locked	QAM256	26	561.0	1.1	43.5	0	0
12	Locked	QAM256	27	567.0	1.2	43.4	0	0
13	Locked	QAM256	28	573.0	1.3	43.5	0	0
14	Locked	QAM256	29	579.0	1.3	43.4	0	0
15	Locked	QAM256	30	585.0	1.2	43.3	0	0
16	Locked	QAM256	31	591.0	1.4	43.2	0	0
17	Locked	QAM256	33	603.0	1.2	43.3	0	0
18	Locked	QAM256	34	609.0	1.2	43.4	0	0
19	Locked	QAM256	35	615.0	1.3	43.4	0	0
20	Locked	QAM256	36	621.0	1.2	43.4	0	0
21	Locked	QAM256	37	627.0	1.2	43.3	0	0
22	Locked	QAM256	38	633.0	1.2	43.4	0	0
23	Locked	QAM256	39	639.0	1.0	43.2	0	0
24	Locked	QAM256	40	645.0	0.8	43.0	0	0
25	Locked	QAM256	41	651.0	0.8	43.2	0	0
26	Locked	QAM256	42	657.0	0.7	42.9	0	0
27	Locked	QAM256	43	663.0	0.8	43.1	0	0
28	Locked	QAM256	44	669.0	0.9	43.2	0	0
29	Locked	QAM256	45	675.0	0.7	43.1	1	0
30	Locked	QAM256	46	681.0	0.3	42.9	0	0
31	Locked	QAM256	47	687.0	0.0	42.6	1	0
32	Locked	OFDM PLC	48	722.0	0.5	42.6	9628284	0

Upstream Bonded Channels

Channel	Lock Status	Channel Type	Channel ID	Symb. Rate (Ksym/sec)	Freq. (MHz)	Pwr (dBmV)
1	Locked	SC-QAM	6	2560	10.4	55.0
2	Locked	SC-QAM	7	5120	16.4	55.8
3	Locked	SC-QAM	8	5120	22.8	54.3
4	Locked	SC-QAM	9	5120	29.2	53.3
5	Locked	SC-QAM	10	5120	35.6	52.8
6	Locked	SC-QAM	12	2560	40.4	51.5

1

0

CCAnna

Problem Solver

•

874 Messages

Hi @user_447f6c, thank you for reaching out over Xfinity Forums. I sure am sorry to hear you have run into problems with your service. This is certainly never what we want for our customers. Our expert has provided wonderful information (thank you, @EG ). Our team would be happy to look at the signals from our end as well. We can also get that technician out to you, if we can't remotely get your service working well. How does that sound?

Can you send us a private message with your full name, name of account holder (if different) and service address? To send a private message, please click the chat icon next to the bell in the upper right corner. Click the “notepad and pen” button. Send the full message to our shared support handle “Xfinity Support”. We look forward to hearing from you!

I no longer work for Comcast.

4 years ago

EG

Expert

•

118.3K Messages

4 years ago

The upstream power is too high / out of spec. 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 !

0

B

BigEvilSquirrel

Visitor

•

2 Messages

4 years ago

Hi, I just purchased a Motorola MB8611 and have the same blinking upstream light and all the same errors. I tried contacting Xfinity help to no avail. They were more interested in selling me more services than helping with the issue.

The manual states the following: "If a blue Upstream or Downstream light blinks continuously, this indicates partial service (at least one designated channel has not completed bonding). You should still get high Internet speeds, but your service provider may want to know so they can adjust their network."

How can I get assistance on this?

0

EG

Expert

•

118.3K Messages

4 years ago

@BigEvilSquirrel

Have you tried to see if any of the tips above that I posted 3 months ago apply ?

2

0

B

BigEvilSquirrel

Visitor

•

2 Messages

@EG The modem is plugged directly to the wall via a single coax. This is simply because Xfinity doesn't want to make signal adjustments. Had an extremely bad experience with tech support. If something doesn't change, I will be contacting the retention department after I call AT&T.

4 years ago

0

XfinityEricB

Official Employee

•

3.3K Messages

We are still here to assist you @BigEvilSquirrel, and I would be happy to help in any way I can. If none of the work done so far has been of assistance, and I can't get it corrected for you I would be happy to send a tech out.

Can you send us a private message with your full name, name of account holder (if different), and service address?

To send a private message, please click the chat icon next to the bell in the upper right corner. Click the “notepad and pen” button. Send the full message to our shared support handle “Xfinity Support”. We look forward to hearing from you!

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

Your Home Network

user_447f6c

Motorola MB8611 Constantly Loses Signal

EG

user_447f6c

CCAnna

EG

BigEvilSquirrel

EG

BigEvilSquirrel

XfinityEricB

New to the Community?