errors in cable modem when computer sleeps

HAVOC said:

I have a Motorola SBG6580 cable modem. When I get up in the morning the only light on the modem is the power light. I have to unplug it (power) and plug it back in for all the lights to show (takes a couple of seconds). I think this only happens if the computers power settings are set to sleep. I'm going to disable sleep and see what it does tomorrow. Running Windows 7 64 bit.

I cannot log into the modem with 192.168.100.1
I cannot access the internet either.

Here are the errors:
SYNC Timing Synchronization failure
No UCDs Received
Lost MDD Timeout
MDD message timeout
No Ranging Response received - T3 time-out

(I bought the modem so Comcast is not going to replace it)

Those are all downstream errors. The modem is having severe issues overnight keeping synchronized with Comcast. It's possible you have problems in your drop line from your house group junction outside to your house, or from a substation to that junction, even.

It's also possible that someone at night in your neighborhood or complex is overloading the network with their pr0n and causing problems.

In short, all of those errors pertain to the modem not being able to communicate with the ISP for reasons OUTSIDE your home.

I would call comcast and let them know your modem is doing that every night. They won't be able to see the logs in your modem (as it's not theirs) but if you can call when the issue happens, that's your best chance of getting them to catch it.

HAVOC said:

It did it again with the computer not in sleep so I don't think it's my network card.
I checked the time and it happened at 5:08 in the morning, before it was a little after 6AM.
I'll call Comcast and save the error log so I can tell them what I see. When the technician came and setup my internet and modem he thought it was strange that my modem was missing it's "configuration file".
It happens almost every morning.
I live in an apartment complex, the cables are underground I believe.

I went to pingtest.net and get 59% packet loss. Not sure if the two are related.
If I ping google.com from cmd, I get 0% loss.

My internet speeds are fine.

What you can also try is when you go to bed (or whatever), unplug your computer from the modem and see if it still dies.

And when I meant "downstream" I meant from the outside in to the modem. No farther than that.

Update: I just thought of something, seeing where you're at.

Is this a DOCSIS 3.0 compatible modem?

HAVOC said:

It's a Motorola SBG6580 which is DOCSIS 3.0 comp.
There is a room in the basement that has all the cable wires in.
Should I check to see if my connection is tight?
If it's loose, I should have problems all the time, correct?

I think Comcast should look outside your house at their lines as well as what's coming into your house.

Do you have cable splitters of any kind attached to your line before your modem?

HAVOC said:

I have a 2-way splitter. My cable comes from the wall into the splitter, one side goes to the TV and the other side goes to the modem. The modem is about 3 feet away from the TV.

Did you get the splitter from Comcast or another source?

This could also be a source of your issues. Try connecting the modem directly without the splitter and see what happens. Sometimes splitters (that don't come from Comcast) can cause too much noise and weaken the signal. Your TV might not notice it, but the modem most certainly will.

HAVOC said:

I'll connect the modem directly and see what happens tomorrow.
The splitter is from Comcast, the tech installed it when he was here.
It's weird that it does this almost the same time that I wake up each day. Could I be turning on/off a light or something that would cause this?

If there's a bad ground that's causing a loss of signal in your cable line, you'd have to get someone out to test the line's signal strength and Signal-to-Noise ratio when you do well... everything. Then finding the problem is another thing.

I'd still put my money on something going wrong either with the splitter or outside your house.