Visitor
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3 Messages
UCD invalid or channel unusable
My Motorola MB8611 cable modem (Hardware Version V1.0, Software Version 8611-19.2.18) logs critical events of type "UCD invalid or channel unusable" every few days and sometimes multiple times a day. My Comcast connection will go down for a few minutes, and then come back up. Using the Xfinity app on my phone during that time runs through a scripted bot that tries to help me by having me check my coax cable connections, power, reboot the cable modem, etc. and I've done all those things multiple times but no improvement. The other critical errors logged are "REG RSP not received" and "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing".
Looking at the downstream bonded channels, there are zero uncorrected errors. The only corrected errors are on channel 33 and 34. What can be done to get my connection to be stable?
EG
Expert
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113.9K Messages
19 days ago
What do the modem's signal status values look like ? Try getting them here;http://192.168.100.1
Please 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.
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EG
Expert
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113.9K Messages
18 days ago
The upstream power is too high, and it may be intermittently fluctuating even higher out of spec. The downstream power is on the low / weak side as well. These 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/reconfigured. 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, or animal chews.
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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