Besides:

1. selecting the wrong digital input
2. getting into 6.1 mode w/o a 6.1 source
3. selecting the wrong digital output off the DVD player

What else can get misconfigured to where there is not any digital sound??????????? Radio & analog sources work fine, little triangle indicating DD/DTS/etc is blinking, which indicates no digital on the current input.

My Dad does this to his HT about every 6 to 9 months.......