I got my 805 about 3 weeks ago and all has been fine until the other day while watching a movie I found it would not switch to Dolby Digital. I checked all of my settings and all looks good as far as I can tell. When I first start the DVD player the reciever is set to dolby digital then when movie starts it will

go to stereo and sometimes back to dolby then ends up at stereo. I cannot force it back to dolby digital at all. I tried a different DVD player and same thing happens. I checked connections and tried different DVDs also. Can any one help me?
Thanks,
Eric