Sorry mod - i did cause some confusion about the brands and models numbers initially.
In a nutshell
I used to connecting my DVD player to my TV for video signal with a set of component video cords and 5.1 audio was carried from DVD player to amplifier with an optical audio cable.
I am replacing the component vieo with HDMI cable (from DVD player to TV). Since this HDMI cable also caries audio i mute the TV audio My optical cord is still carrying the audio signal to the amplifier
Result - the amplier shows 2 channel stereo audio signal carried rather than 5.1 audio signal ever since the HDMI cable is attached
On removing the HDMI cable and switching back to component the audioreturns to 5.1
Needed to understand the downgrading of audio when HDMI was experimented with
DVD player is Pioneer 490V
Sorry for the confusion. I hope i am more clear now!