3 Messages
Modem intermittently goes offline for a few minutes
- After purchasing it a month ago, my brand new Motorola MB8611 modem has been disconnecting randomly for about a week. It's often enough to be a big problem and I've been getting by off WiFi from my phone data.
- When I notice the internet go out, I check the modem and invariably all indicators -- Downstream/Upstream/Online/LAN -- are dark with the exception of the power light.
- After a few minutes they light up again and traffic's restored.
- I plugged the modem directly into my PC bypassing any other network equipment and the issue persists.
- I've restarted my modem + router multiple times throughout troubleshooting.
Event log:
| Time | Priority | Description | |
| 06:47:17 Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 07:53:02 Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 08:27:58Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 08:34:06 Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 08:52:44Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 08:56:48 Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 09:20:30 Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 09:39:02 Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 10:23:03 Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);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=(redacted);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| Time Not Established | Notice (6) | Honoring MDD; IP provisioning mode = IPv6 | |
| 12:52:32 Mon Sep 4 2023 | Notice (6) | DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; | |
| 12:52:40Mon Sep 4 2023 | Critical (3) | UCD invalid or channel unusable;CM-MAC=(redacted);CMTS-MAC=(redacted);CM-QOS=1.1;CM-VER=3.1; |
Downstream Bonded Channels:
| Channel | Lock Status | Modulation | Channel ID | Freq. (MHz) | Pwr (dBmV) | SNR (dB) | Corrected | Uncorrected |
| 1 | Locked | QAM256 | 20 | 567.0 | -1.5 | 43.3 | 0 | 0 |
| 2 | Locked | QAM256 | 1 | 453.0 | -0.7 | 44.3 | 0 | 0 |
| 3 | Locked | QAM256 | 2 | 459.0 | -0.2 | 44.5 | 0 | 0 |
| 4 | Locked | QAM256 | 3 | 465.0 | -0.4 | 44.4 | 0 | 0 |
| 5 | Locked | QAM256 | 4 | 471.0 | -0.7 | 44.3 | 0 | 0 |
| 6 | Locked | QAM256 | 5 | 477.0 | -0.4 | 44.2 | 0 | 0 |
| 7 | Locked | QAM256 | 6 | 483.0 | -0.3 | 44.3 | 0 | 0 |
| 8 | Locked | QAM256 | 7 | 489.0 | 0.2 | 44.6 | 0 | 0 |
| 9 | Locked | QAM256 | 8 | 495.0 | -0.2 | 44.4 | 0 | 0 |
| 10 | Locked | QAM256 | 9 | 501.0 | -0.5 | 44.2 | 0 | 0 |
| 11 | Locked | QAM256 | 10 | 507.0 | -0.5 | 44.3 | 0 | 0 |
| 12 | Locked | QAM256 | 11 | 513.0 | -0.6 | 44.2 | 0 | 0 |
| 13 | Locked | QAM256 | 12 | 519.0 | -0.5 | 43.9 | 0 | 0 |
| 14 | Locked | QAM256 | 13 | 525.0 | -1.2 | 43.8 | 0 | 0 |
| 15 | Locked | QAM256 | 14 | 531.0 | -1.4 | 43.5 | 0 | 0 |
| 16 | Locked | QAM256 | 15 | 537.0 | -1.8 | 43.2 | 0 | 0 |
| 17 | Locked | QAM256 | 16 | 543.0 | -2.1 | 43.0 | 0 | 0 |
| 18 | Locked | QAM256 | 17 | 549.0 | -2.1 | 42.8 | 0 | 0 |
| 19 | Locked | QAM256 | 18 | 555.0 | -2.4 | 42.7 | 0 | 0 |
| 20 | Locked | QAM256 | 19 | 561.0 | -2.1 | 42.8 | 0 | 0 |
| 21 | Locked | QAM256 | 21 | 573.0 | -1.4 | 43.3 | 0 | 0 |
| 22 | Locked | QAM256 | 22 | 579.0 | -1.2 | 43.4 | 0 | 0 |
| 23 | Locked | QAM256 | 23 | 585.0 | -1.1 | 43.5 | 0 | 0 |
| 24 | Locked | QAM256 | 24 | 591.0 | -1.0 | 42.6 | 0 | 0 |
| 25 | Locked | QAM256 | 25 | 597.0 | -0.7 | 43.2 | 0 | 0 |
| 26 | Locked | QAM256 | 26 | 603.0 | -0.8 | 43.6 | 0 | 0 |
| 27 | Locked | QAM256 | 27 | 609.0 | -0.4 | 43.9 | 0 | 0 |
| 28 | Locked | QAM256 | 28 | 615.0 | -0.8 | 43.7 | 0 | 0 |
| 29 | Locked | QAM256 | 29 | 621.0 | -0.5 | 43.6 | 0 | 0 |
| 30 | Locked | QAM256 | 30 | 627.0 | -0.2 | 43.7 | 0 | 0 |
| 31 | Locked | QAM256 | 31 | 633.0 | -0.9 | 43.6 | 0 | 0 |
| 32 | Locked | QAM256 | 32 | 639.0 | -0.3 | 43.9 | 0 | 0 |
| 33 | Locked | OFDM PLC | 193 | 957.0 | -1.5 | 43.0 | 4653308 | 0 |
Upstream Bonded Channels:
| Channel | Lock Status | Channel Type | Channel ID | Symb. Rate (Ksym/sec) | Freq. (MHz) | Pwr (dBmV) |
| 1 | Locked | SC-QAM | 17 | 5120 | 16.4 | 48.5 |
| 2 | Locked | SC-QAM | 18 | 5120 | 22.8 | 48.8 |
| 3 | Locked | SC-QAM | 19 | 5120 | 29.2 | 49.3 |
| 4 | Locked | SC-QAM | 20 | 5120 | 35.6 | 50.0 |
EG
Expert
•
111.3K Messages
2 years ago
Please redact all of the CM MAC and the CMTS MAC addresses from your error log entries for your privacy. They are considered to be personal information. The posting of personally identifiable information is a violation of their forum guidelines. The forum bot will not allow your post to be seen publically. It flagged your post as "Private".
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EG
Expert
•
111.3K Messages
2 years ago
OK thanks. It's publicly viewable now. The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. 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 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 from Home Depot, Target, Wal-Mart, 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, abrasions, 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 !
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EG
Expert
•
111.3K Messages
2 years ago
Yeah, those are pretty sharp, approaching 90 degrees. More rounded is better. Those bends may or may not be the direct cause of the high upstream power, but they can cause problems like signals walking off the wire / reflections / impedance variations. The internal shielding can open up / come apart and allow noise to ingress the line. Definitely start there with improved wiring runs !
P.S. Just adding that that entire section should be replaced, not just straightened out !
(edited)
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