plasma resolution issue

[johndoe7999]

hi all

my setup:
plasma samsung ps50b430
a/v receiver onkyo tx - nr 609
bluray sony bdp S370
speakers Bose acoustimass 10

just replaced my old a/v receiver onkyo 506 by the above one. but once i play a bluray the plasma resolution is netted even at 576p. bluray is thru onkyo hdmi input and sound thru optical.

previously my bluray was connected directly to plasma hdmi @ 576p clear pix as 720 or 1080 the picture would be split in 2 parts.

please help

thanks