RBR20 Losing internet connection about 1-2 times / day

I'm not looking for the canned response.  I already read though those posts and it appears that none of that ever helped anyone.

Some items that I mentioned previously and some additional feedback:

1. router worked flawlessly until 1.5 weeks ago. 

2. No configurations were changed

     a.  with the exception of the updated firmware - which made no difference

     b.  update via telnet to the lease time (I really had high hopes for this one)

3. no additional devices have been introduced

4. Lan port also has no internet access (meaning it is not just a wireless thing)

5. Connectivity via lan or via wifi to the router is just fine, only the connection between the router and the cable modem is lost

6. Tried a different ethernet cable, and checked to make sure the cable was not loose

7. Geographically isolated from neighbors and other wifi connections (mine is the only one in range)

8. Satellites are unplugged to rule out some problem with them

9. Problem fixes itself within 5 minutes or so without intervention - no unusual log entries

I have no ability to access my modem's diagnostic / log info, but my ISP has confirmed that they see no outages to the actual internet.  I was able to plug devices directly into the modem and they worked right away.  It does not have any model info on the modem itself, provided by Charter Communications now Spectrum.