Motorola SB6121 Recurring Loss Of Cable Signal Every Day For Five Months

My Motorola SB6121 DOCSIS 3 modem is connected to a Medialink n-band router. Sometime in the morning (usually between 7am and 9am, the router loses the ability to see the modem. I can access the router's control panel, and I see 0.0.0.0 for WAN IP, Subnet Mask, and Gateway. Primary and Secondary DNS server are both blank. Connection Mode is Dynamic IP.I lose the ability to access the modem's control panel directly (192.168.100.1), even though the PC I use is hardwired to the router. So, I unplug the modem, unplug the router, wait, plug in the modem, plug in the router, and everything works again.I've had more than twelve service calls. Every Charter tech looks at the line, puts in boosters, takes out boosters, replaces splitters, and seems to only look at signal. I've BEGGED Charter to let me speak to an engineer, because my suspicion is that it's something to do with the DHCP server.

I did, by the way, replace EVERYTHING.I have had 5 different modems...same problem. I have had 5 different routers...same problem, including a modem/router combo.I've tried different brands, too.I've disconnected all wifi devices from the router, and rebuilt my PC's operating system. I've even unplugged the refrigerator, because one Charter tech claimed it was "upstream noise."I've been online only a few times when the system actually goes down. What I notice in the router logs is this: [code] So at 9:34, no ranging response - T3 timeout, followed by Unicast Ranging Received Abort Response;
then the Cable Modem Reboot due to T4 timeout, and the system time goes to 1/1/1970 at midnight. No ToD.

The last piece of information: Charter installed a second modem as a "test." That was originally in the same room. A month ago they did another line from the box directly to the test modem to skip the splitter on the house.That modem shows the same problems, EXCEPT -- not perfectly in sync. I might see the same error, but the time will be a few minutes and seconds off. And sometimes I'll see the errors, but the modem won't go down.Sometimes the first modem goes down, sometimes the second. I'm accustomed to a router "healing" itself when the modem goes down.It might be off for a bit, but then will re-establish. This Medialink doesn't do that. It forces a physical restart every day. There are other outages too, and all I get from Charter is "the signal strength is good."