Panasonic HT-920 receiver/dvd flashing in front with no sound
I have a Panasonic HT-920 and I really like it. Great HTIB. However, I have noticed that when a station is broadcasting in 5.1 when I change it to the station that sometime the front of the receiver/DVD flashes with no sound for 10 seconds or so and sometimes the sound comes in and other times I have to change the station and then the sound comes in. It is not always when it is in 5.1 but it seems that a lot of times it is when it changes from 5.1 to Dolby and pro logic II. Does anyone know what this could be? Is this a problem from the source or is it a problem from my receiver? Any info would be appreciated.