Dolby Digital switching to Pro-Logic

[toneystone]

I have an Onkyo TX-DS575 hooked to DirecTV HD DVR Receiver. On Dolby Digital brodcasts, the audio signal first appears DD on my Onkyo but then after about 30 minutes, it suddenly switches to Pro Logic. Also on some HD channels (which are in DD 5.1), my Onkyo only decodes DD 2.0 which is Pro Logic. I have another Onkyo which is TX-SR605 and of course I do not have this issue. Anybody know why this is occurring?

[yoda313]

This may not entirely be your situation but not all hd channels pipe a full 5.1 dolby digital signal 100% of the time.

Sometimes they will switch to stereo because they are not encoded in surround sound.

In fact I was suprised while watching the NHL winter classic on NBC yesterday and the high def feed was a 100% 5.1. Even all the commercials - although not all had surround effects of course.

But the point is not all broadcasts on hd will be in 5.1. A lot of older shows will not be in 5.1. Even shows like Seinfeld probably aren't 5.1 - unless they take a remix from a dvd set for the hd broadcast?

ANyway that may or may not be your issue. It is just something to pay attention to.

[toneystone]

Yoda, I dont have this problem with my Onkyo TXSR-605, only with my TXDS-575!

[yoda313]

Check with the connections. Are there any loose cables maybe?

I know when I have used the fiber optic cable switcher I use for 3 to 1 hook ups it can transmit in only stereo if its not lined up a 100%.

Just throwing out ideas there.

[Epicurus8a]

Check to make sure the TXDS-575 has enough ventilation. You might also want to try a cooling fan.
If these suggestions don't help, you might have to service the unit.

Good luck!

Edit:

Did you try swapping DVD players?