c6900 loses internet daily (also time is off on modem)

[ljsiegel]

My c6900 has been having a problem for several months. Usually at least once a day, typically around 1pm PT, it will go offline for 2-3 minutes. Sometimes we power cycle the router. Sometimes we wait it out. It may happen one or two other times in the day but it's pretty reliably goes out around 1pm.

In checking the admin panel, I notice the time is off by 1 hour. Daylight savings time doesn't seem to be recognized. I can't see any place in the router admin to change it. And I had a long chat with Xfinity tech support (2nd level) and they said it wasn't an issue on their end. We tried doing a factory reset and the problem remained.

Is this a bad router?

Something on Xfinity's end?

The router is only about a year old. I'm including a pic of the router stats though I don't know how to interpret that. 

Thanks!

Linda

[FURRYe38]

Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 

Possible faulty modem if a reset doesn't clear the problems. 

[plemans]

Do you have a screen snip of the logs? 

You're power levels aren't horrible but there's some seperation (should all be within 3.5dbmv of each other on downstream) and your upstream is low (still in spec but boarderline). the screen snip only shows the powerlevels when its loaded and perhaps during that time the levels are dropping, causing it to have issues. 

that's where the logs can help. 

Like @FURRYe38 said, check for splitters, attenuators, or amplifiers in the line. And check the cable. 

[ljsiegel]

Could it have something to do with date/time? I noticed in the log it got reset to 1970 right around the time it crapped out. 

Here's from the Event Log.

There was also something in the plain Log but it might have gotten flushed with other messages. Is there a way to get full log history?

[ljsiegel]

Here are the latest logs.

We had a failure today at 1:11PM (shows as 12:11PM as the router is off by one hour). Included in the PDF is a grab of the Logs and Event Log as well.

Do I need a new modem/router? I'm tempted to get one from Xfinity to see if this resolves the problem. Frustrating....

Thanks in advance for any guidance,

Linda

[plemans]

the "dynamic range window" violations that you're getting indicate the power spiking/fluctuating enough that it goes out of spec. Which can cause the drop/reboots.
Make sure there aren't any splitters, amplifiers, attenuators in your coax line. If there's not, then you need your isp to check the line.
Its still possible that its the modem but it usually is the line when you're getting that notice.