Basic Internet Connectivity And Modem Help

[Ch-hart83]

Hello, let me start by sort of explaining the situation a bit.

Every night, between 7pm and 3am or so, my connection drops like crazy. I've called comcast about this before and they suggested it was my modem. So I said fine, bought my own modem and it worked great for a month or so. Then the problem came back again.

For awhile, I found a strange solution for the problem. If I unplugged the cable cord(I cannot think of the actual name of it for some reason) from the modem for a couple minutes, and hooked it back in, it'd fix my net for a few hours. But eventually it would go down again later till I did the technique again. And while that was fine for awhile, it has gotten worse. Now even this trick will only keep me online for a couple minutes at a time.

As i've said, i've called comcast before. They've sent technicians out before but as soon as they see the lights solid for 1 second, they're out the door and my net is down 5 minutes later. After that, i've refused to let anymore technicians come out because they are zero help.

Well after all that, I called comcast again, and of course, they blamed my modem yet again and said I need to go get yet another new one. I just got this modem a year ago... but it looks like I have no choice again, but I decided before I blew money on yet another new modem, I'd see if I could get a better diagnosis from the forums here.

Downstream

-9.0 dBmV powerlevel
38.1 db SNR

Not sure on Upstream

modem is listing 54.0 dbmv for Power though

LOGS

2012-07-31 21:25:14 3-Critical T001.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-31 20:57:15 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-31 20:57:15 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
1970-01-01 00:01:17 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
1970-01-01 00:01:17 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:39 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
1970-01-01 00:01:20 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
1970-01-01 00:01:20 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:47 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
1970-01-01 00:01:22 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
1970-01-01 00:01:22 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:49 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-31 20:32:57 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-31 20:32:57 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:27 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
1970-01-01 00:00:22 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:00:17 3-Critical T001.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
1970-01-01 00:00:11 6-Notice M571.1 Ethernet link up - ready to pass packets
1970-01-01 00:01:21 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
1970-01-01 00:01:21 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-31 20:22:50 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-31 20:22:50 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:12 6-Notice M572.0 Ds Lock Failed - Reinitialize MAC...
1970-01-01 00:00:08 3-Critical T001.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
1970-01-01 00:01:20 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
1970-01-01 00:01:19 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
1970-01-01 00:01:21 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
1970-01-01 00:01:21 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-31 20:10:35 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-31 20:10:35 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-31 20:06:56 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-31 20:06:56 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-31 19:55:23 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-31 19:55:23 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
1970-01-01 00:00:09 6-Notice M572.0 Ds Lock Failed - Reinitialize MAC...
1970-01-01 00:00:09 3-Critical T001.0 SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing
1970-01-01 00:00:09 6-Notice M572.0 Ds Lock Failed - Reinitialize MAC...
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-31 19:13:05 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-31 19:13:04 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
1970-01-01 00:00:08 6-Notice M571.1 Ethernet link up - ready to pass packets
2012-07-31 18:59:38 6-Notice M573.0 Modem Is Shutting Down and Rebooting...
2012-07-31 18:59:37 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance o
2012-07-31 18:58:59 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
1970-01-01 00:22:01 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:21:52 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:21:42 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:21:35 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:21:25 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:21:10 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:21:00 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:20:51 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:20:41 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:20:17 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:20:07 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:19:58 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:19:48 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:19:37 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:19:27 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:19:18 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:19:08 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:18:58 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:18:48 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:18:38 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:18:28 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:18:12 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:18:01 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:17:46 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:17:36 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:17:18 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:17:08 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:16:56 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:16:46 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:16:41 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:16:31 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:16:20 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:16:10 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:15:47 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:15:37 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:15:26 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:15:16 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:14:50 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:14:40 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:14:22 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:14:12 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:14:07 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out
1970-01-01 00:13:57 3-Critical R002.0 No Ranging Response received - T3 time-out 
1970-01-01 00:13:37 3-Critical R001.0 No Maintenance Broadcasts for Ranging opportunities received - T2 time-out

MODEM MODEL: Motorola SB5101U

Router Model: Linksys E1200 (I think)

-Have had a comcast tech visit in the past, though not recently

-Lights on the modem reset, blink as though the modem is coming back on. Never gets past "Send"

[EG]

The power levels are out of spec. That will cause random disconnects and spontaneous re-booting of the modem. Are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured ?

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 putting them back together again, then perhaps it's best to book a tech visit to investigate and correct.

[Ch-hart83]

Thanks for the response.

I did forget to mention that. A few months ago I went through and eliminated all the splitters(all the splitters indoors, I actually haven't looked around outside) and gave my modem a nice direct line. And it really did help for awhile, but as usual, the problem came back a few weeks later.

I guess I'll see if I can get another tech out here on my next day off

[EG]

If a premise facing tech can not find / fix an issue at your home then it is they who are responsible to escalate an issue to their line / maintenance dept. techs to investigate the neighborhood infrastructure.

[19Grumpah42]

Your upstream level is way too high for satisfactory performance, it should be less than 50 mV   This is the servo voltage the modem thinks is required to generate a viable handshake.

You have a bad hardwire connection coming into your modem.

I had this problem recently. Turned out that squirels had chewed on the cable coming into the house, and there was actually water inside the coax, all the way up to the inside ground connection. Comcast replaced the entire run from the street to the house and it is now fine. I have only experienced very professional behaviour from the Comcast technicians visitng my house.

Best of luck.

--Grahame

[EG]

FWIW, both power levels are out of spec and indicate excessive overall attenuation somewhere.