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Frank0123's avatar
Frank0123
Follower
Apr 01, 2020

CM400 modem - Intermittent connection problem

Hi,

I have a persistent intermittent connection issue going on for ~1yr, and lived with it until I started wfh. My connection normally works fine, then drops for 45-60seconds, 4-20 times a day (I have a ping log tracking outages).

 

Things I've tried so far:

1. I have a modem, router & 24 port switch normally connected. I experience the same problem whether I'm:

a) Using wifi or wired

b) Using latop, desktop, phone or ipad

c) Doesn't matter how often I reboot

d) Have tried taking my cable modem outside connected directly to cable drop, hardwired into my laptop - same issues (i.e. bypassing all itnernal wiring, routers, wifi and switches)

e ) Replced cable modem tried Arris, and two different Netgears - currenlty using CM400

 

Called comcast:

2. Replaced cable drop to my house

3. Reterminated by internal cable connections

4. Retested all the wiring into my modem

5. On all occasions I get the standard "everything looks good, great SNR and power levels

6. Today I was told "not our problem, everything is fine, you need to call NetGear"

 

Any help or suggestions would be appreciated, below are the modem stats and event log

 

Cable Connection
 
 
 
 
 
 
<tabindex=-1>Startup Procedure</tabindex=-1>
ProcedureStatusComment
Acquire Downstream Channel687000000 HzLocked
Connectivity StateOkOperational
Boot StateOkOperational
SecurityEnabledBPI+
IP Provisioning ModeHonor MDDhonorMdd(4)
Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUnCorrectables
1LockedQAM 25640645000000 Hz5.1 dBmV37.0 dB7316613
2LockedQAM 25641651000000 Hz4.9 dBmV37.3 dB8618530
3LockedQAM 25642657000000 Hz4.8 dBmV37.3 dB9243477
4LockedQAM 25643663000000 Hz4.6 dBmV37.3 dB7454551
5LockedQAM 25644669000000 Hz4.5 dBmV37.6 dB4396705
6LockedQAM 25645675000000 Hz4.4 dBmV37.3 dB4085659
7LockedQAM 25646681000000 Hz4.4 dBmV37.3 dB4351628
8LockedQAM 25647687000000 Hz4.4 dBmV37.3 dB41551532
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA215120 Ksym/sec19300000 Hz41.8 dBmV
2LockedATDMA225120 Ksym/sec25700000 Hz41.5 dBmV
3LockedATDMA235120 Ksym/sec32300000 Hz42.3 dBmV
4LockedATDMA245120 Ksym/sec38700000 Hz42.8 dBmV
Current System Time: Tue Mar 31 20:20:07 2020
System Up Time: 07:25:01
 
 

Event log

 
 
 
 
 
 
TimePriorityDescription
Dec 18 02:51:12 2019Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
Dec 18 02:51:33 2019Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Dec 18 04:27:07 2019Critical (3)SYNC Timing Synchronization failure - Loss of Sync
Dec 18 04:27:12 2019Warning (5)Lost MDD Timeout
Dec 18 04:29:30 2019Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
Dec 18 04:32:33 2019Critical (3)No Ranging Response received - T3 time-out
Dec 18 04:32:43 2019Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Dec 18 04:32:45 2019Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out
Jan 2 15:32:22 2020Critical (3)No Ranging Response received - T3 time-out
Jan 23 20:50:46 2020Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Feb 2 17:26:03 2020Critical (3)No Ranging Response received - T3 time-out
Feb 19 01:48:32 2020Critical (3)SYNC Timing Synchronization failure - Loss of Sync
Feb 19 01:48:33 2020Critical (3)No Ranging Response received - T3 time-out
Feb 19 01:50:34 2020Critical (3)SYNC Timing Synchronization failure - Loss of Sync
Feb 19 01:50:41 2020Critical (3)No Ranging Response received - T3 time-out
Feb 19 03:56:59 2020Critical (3)SYNC Timing Synchronization failure - Loss of Sync
Feb 19 03:57:06 2020Critical (3)No Ranging Response received - T3 time-out
Feb 19 04:03:43 2020Critical (3)SYNC Timing Synchronization failure - Loss of Sync
Feb 19 04:03:48 2020Critical (3)No Ranging Response received - T3 time-out
Mar 12 15:50:34 2020Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Mar 15 10:44:35 2020Critical (3)No Ranging Response received - T3 time-out
Mar 22 06:13:10 2020Critical (3)SYNC Timing Synchronization failure - Loss of Sync
Mar 22 06:17:58 2020Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Time Not EstablishedCritical (3)No Ranging Response received - T3 time-out
Mar 22 06:20:04 2020Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Mar 22 16:29:00 2020Critical (3)SYNC Timing Synchronization failure - Loss of Sync
Mar 22 16:31:56 2020Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Mar 29 12:11:46 2020Warning (5)TEK Invalid - Invalid Key Sequence Number
Mar 30 10:04:09 2020Warning (5)Lost MDD Timeout
Mar 30 10:05:54 2020Critical (3)SYNC Timing Synchronization failure - Loss of Sync
Mar 30 10:05:59 2020Warning (5)Lost MDD Timeout
Mar 30 10:08:19 2020Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
Mar 30 10:09:28 2020Warning (5)Lost MDD Timeout
Mar 30 10:09:45 2020Critical (3)Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
Mar 30 10:10:27 2020Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Mar 30 10:10:28 2020Warning (5)RCS Partial Service
Time Not EstablishedCritical (3)No Ranging Response received - T3 time-out
Mar 30 12:59:06 2020Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Time Not EstablishedCritical (3)No Ranging Response received - T3 time-out
Mar 31 12:55:47 2020Warning (5)MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
 
 

2 Replies

  • FURRYe38's avatar
    FURRYe38
    Guru - Experienced User
    Apr 01, 2020

    Try a different modem with your ISP to see if problem still appears? 

     

  • peterfair1's avatar
    peterfair1
    Aspirant
    Apr 05, 2020

    I have/had a CM 400 using high speed Spectrum ISP. Back in December 2019 my speeds dropped drastically with internet dropping out anywhere from 5-20x a day. I contacted customer support, they ran test telling me everything was fine, THEN sold me on a 6 month plan in case I needed help. Internet continued dropping out anywhere from 5-20x a day. Now, I find out they are/were aware of this hardware problem but still sold me a 6 month plan. When I called today to tell them the situation and that I was sold a plan when I didn't need it and wanted a refund, they responded by telling me "in the e-mail contract we sent you, it says that ater 10 days, there are NO REFUNDS".

     

    I'm pissed off about this type of practice and ill NEVER buy netgear products again because of it.

     

    *I had purchased a replacement CM400 to use, but the service rep told me I could take it back because there was nothing wrong with the one I had... (rolls eyes).