Good News - Finally! Sound dropouts apparently fixed
Watching tonight's local news (WTVD) I noticed almost immediately that there were no dropouts. The problem had gotten really bad over the past few weeks. I checked the system information (Menu/6-1-3) and sure enough, I now have software v616. Apparently 615 was scuttled. I read some complaints here that 615 introduced some problems not seen in 614, which was my previous version.
As best I can tell, the sound dropouts are completely gone now. I'm still not totally pleased with Dish since it took so long to get this fixed, but at least it does seem to be fixed.