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Linksys CM100 Cable modem constantly restarts

I have a Linksys CM100 cable modem that has been regularly resetting itself.  Every 5 - 20 minutes the connection is lost, the lights go out and then they flash back on.  It never has a problem reestablishing the connection.  My ISP hasn't been very helpful and they keep saying I should try a new modem.  It has been working flawlessly for more than a year and this started about 5 days ago.  Any ideas on what could be causing this behavior?  If the modem was bad why would it work at all?  Here's some recent output from the logs:

11/7/2010 13:00criticalUCD invalid or channel unusable
11/7/2010 13:01errorImproper Configuration File CVC Format
11/7/2010 13:06criticalReceived Response to Broadcast Maintenance Request, but no Unicast   Maintenance opportunities received - T4 timeout
11/7/2010 13:06criticalSYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol   timing
11/7/2010 13:06errorImproper Configuration File CVC Format
11/7/2010 13:49informationDCC depart old
11/7/2010 13:49informationDCC arrive new
11/7/2010 13:49criticalNo Ranging Response received - T3 time-out
11/7/2010 13:49errorDCC-ACK not received
11/7/2010 13:49criticalNo Ranging Response received - T3 time-out
11/7/2010 13:50criticalReceived Response to Broadcast Maintenance Request, but no Unicast   Maintenance opportunities received - T4 timeout
11/7/2010 13:50criticalDCC aborted unable to communicate on new upstream channel
11/7/2010 13:50criticalUCD invalid or channel unusable
11/7/2010 13:50errorImproper Configuration File CVC Format
11/7/2010 12:59informationDCC arrive new
11/7/2010 12:59criticalNo Ranging Response received - T3 time-out
11/7/2010 12:59errorDCC-ACK not received
11/7/2010 13:00criticalNo Ranging Response received - T3 time-out
11/7/2010 13:00criticalReceived Response to Broadcast Maintenance Request, but no Unicast   Maintenance opportunities received - T4 timeout
11/7/2010 13:00criticalDCC aborted unable to communicate o

And some info on the modem itself:

Standard Specification              Compliant DOCSIS 2.0
Hardware Version V54.0
Software Version 0.0.6.13170

Downstream   Channel
Lock Status Operational
Modulation 256QAM
Channel ID 197
Provisioned Rate Unlimited
Symbol Rate 41879.195 Ksym/sec
Downstream Power 2.0 dBmV
SNR 38.0 dB
Upstream Channel
Lock Status Operational
Modulation 16QAM
Channel ID 2
Provisioned Rate Unlimited
Symbol Rate 2560 Ksym/sec
Upstream Power 43.0 dBmV

Are these numbers normal?  Any ideas about this would be appreciated!  Thank you

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2 REPLIES
New Member

Re: Linksys CM100 Cable modem constantly restarts

Hey James,

Join the club. I have Charter as my ISP and both my modem/router and my Internet service worked flawlesly until now. I get the same error and they just wouldn't admit it's them. They finally declared an outage in my area yesterday and they fixed it late last night only to come back this morning again. So now they won't even admit it's them again but the simptoms are exactly the same. Good luck to you !!!

PS: your modem and PC are FINE !!! Don't waste your time going thru the scripted technical support unless you want to waste one hour of your life for nothing. Ask to speak to tier 2 support or above directly and read the errors you are getting. They started recently offering 60Mbps speeds but didn't think they will have to upgrade their equipement so now the lines are getting saturated.

Mon Nov 08 10:21:56 2010    82000500   Critical (3)   Started Unicast Maintenance Ranging - No Response received - ... 

Mon Nov 08 10:17:52 2010    66060300   Error (4)   Map Request Retry Timeout 

Mon Nov 08 10:16:31 2010    68000401   Warning (5)   ToD request sent - No Response received 

Mon Nov 08 10:16:22 2010    82000200   Critical (3)   No Ranging Response received - T3 time-out 

Mon Nov 08 10:16:14 2010    84000100   Critical (3)   SYNC Timing Synchronization failure - Failed to acquire QAM/Q... 

Mon Nov 08 10:16:02 2010    82000400   Critical (3)   Received Response to Broadcast Maintenance Request, But no Un... 

Mon Nov 08 10:15:29 2010    68000401   Warning (5)   ToD request sent - No Response received 

Mon Nov 08 10:15:13 2010    82000400   Critical (3)   Received Response to Broadcast Maintenance Request, But no Un... 

Mon Nov 08 10:14:42 2010    82000500   Critical (3)   Started Unicast Maintenance Ranging - No Response received - ... 

Mon Nov 08 10:05:58 2010    68000401   Warning (5)   ToD request sent - No Response received 

Mon Nov 08 10:05:47 2010    82000200   Critical (3)   No Ranging Response received - T3 time-out 

Mon Nov 08 10:05:40 2010    82000400   Critical (3)   Received Response to Broadcast Maintenance Request, But no Un... 

Mon Nov 08 10:05:10 2010    82000500   Critical (3)   Started Unicast Maintenance Ranging - No Response received - ... 

New Member

Re: Linksys CM100 Cable modem constantly restarts

Update!

It turns out it actually was my Linksys modem.  I had a tech come to my house and replace some old spliters and such and gave me new

coax cable.  The signal improved but my modem still kept resetting to my frustration.

Tonight I replaced it with a Motorola SB6120 and so far my connection has been strong and steady for 5 hours and the log shows no errors!  I am crossing my fingers that it stays that way.  My CM100 reset again just before I replaced it, lol

http://www.motorola.com/Consumers/US-EN/Consumer-Product-and-Services/Cable-Modems-and-Gateways/SURFboard-Cable-Modem-SB6120-US-EN

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