I did try with the AMP turn on and with the trigger wire removed, the sound I always get is just some clip in the speakers, at night time when it is real quiet, I can hear some dialoge from the movie through the speakers but very tiny, this means the hookup is correct.
My Adcom preamp is working fine today allows me to confirm 990 did turn on my AMP from triggering, and the amp still good like before. Something annoying me is that whenever I switch the source from DVD to Video1 (directv), there is a popping sound, whenever I increase/decrease volume, there is popping sound for each step increase or decrease.
I may bring my 990 to a friend's home to hook up to his amp tonight, at this point, I think there is something wrong in my 990. Let me ask you a question, when I received the 990, there is 2 layers of tape on the inner box of the unit. I carefully removee the outer layer of tape the inner one was cut out already (not factory sealed), would that mean it was a return unit that has problem before? though inside the box, everything seems to be new and unused.