May be I should add a few more points here that whenever I changed from any source to other source like DVD to video 1, I can here a ping and if I increase or decrease the volume, a similar sound happened with every step the volume went up or down, made it quite annoying. Thanks.

Setting up the DC trigger may also require you to set it up on the amps end as well. Read the manual on the amp and make sure you have followed the steps described in setting up the amp for DC trigger operation. I had this same problem with my previous amp, an ATI, and found that the amp needed to be set up for using the DC trigger function.

Thanks, Merc. I looked at the manual of the AMP, did not say much. The Amp turn on and off through the trigger as I turn the 990 on off. Even if I disable the trigger and leave the AMP on still has no sound. At night time I can hear the voice and sound came out from speaker but so tiny and there is a crack sound or should call it clip sound from speaker whenever I change source and turn on the volume higher or lower, there is always 1 clip with every one step volume change. I am so confused!

I also had similar problems setting up my 990 with an adcom 7607, but i solved them.
First, would set up without the trigger and see if you can make the amp and preamp work without it.If it still doesnt work, then something is wrong with your connections or with the 990 (I am assuming your amp is working, though you did say your 750 died -fuses?)
If the amp/preamp works, then it might be the trigger cord. I bought a stereo one originally that would not transfer the trigger signal between my adcom 7607 and the 990.
If you are not very familiar with the controls that mught be part of your problem -- it was with me. Finally, i pressed the tuner button on the right of the second row from the top , then the video buttons bottom two rows to change from tuner to my inputs.
Hope this helps.

Thanks Martialovid, I had been using a stereo trigger wire for my Adcom set until the Adcom Preamp freezed more and more often, when it did, there is no volume or any key control neither with front panel switch or remote except using front panel switch to turn off unit, then it would come on blank screen with no sound, no control, sometime later you might be able to turn it on again normally but only lasted a little while then the same thing happened again.
I bought the 990 to replace it. The stereo trigger did turn on the Adcom GFA-7500, but the sound came out from speakers are so tiny almost impossible to hear. Last night I tested with the trigger wire left between 990 and GFA-7500, but put the speaker wires and the coaxial out from 990 back to the Adcom GTP-750 preamp (with all units off), when I turned on the 990, the trigger turned on the Amp and after the Adcom is on, sound came out OK (Adcom Preamp still work sometime). That means trigger from 990 can turn on the Amp. I will still try to find a mono trigger wire to try though may not be the problem.
I don't quite know what you mean press the tuner button then the video buttons to change from tuner to my inputs, I did try it but no difference. Could you be more specific?

did you hook up the preamp and amp without the trigger? You have to turm the amp on first to avoid a popping noise. If you did, and the units operates, your problem is simply that you are using a stereo connector instead of a mono connector for the trigger. (your adcom 750 is probably fine)

As for the remote for the 990 . When i first started using the unit i was careless where i placed my fingers and often at first pushed buttons by accident. I still do sometimes, when i pick the remote up. Sometimes, this sets the clicker so it will not change inputs. Pushing the button marked tuner in the upper right of the unit, just below the one marked tv and THEN your input button located along the bottom three rows at the bottom of the clicker changes your input. (I think it resets theclicker to operate the preamp controls instead of a particular input) Hope this helps martialovid

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.

Is your amp working? From what you wrote it sounds like you are saying two preamps arent working correctly -- that is less likely than one piece of equipment not working. It sounds like you amp isnt adding to the preamp signal, just passing on the preamp signal that it has received. maybe you need to take your amp also to your friends and also hook it up to his preamp,
As for the 990 --
I am sure you did NOT get a returned item -- Outlaw is meticulous in labeling B items when they sell them on their web site (in a special part of the site). They dont just rebox and mail out as if still new.
I think you need to call the Outlaws and talk directly to them after you check out your equipment at your friends. -- the Outlaws are wonderful at supprting their customers. good luck.

I can't wait until tomorrow to talk to Outlaw, I believe you are right it is a piece of new equipment.
My AMP was working, my Adcom preamp had problem often but still working sometime, so I want to replace it with 990. It usually freezed after playing a little while then nothing can be controlled, so the Adcom preamp is definately not good. I suspected my Amp yesterday too so last night I left the trigger wire hook up between 990 and amp but pull out all speaker wires and coaxial cable (digital out) from 990 and hookup back to Adcom Preamp, the set up was just like before I had the 990 except the trigger. When I turn on 990 it turn on the Amp, I also turn on the Adcom preamp, the sound came out OK, this mean the amp is good and 990 did trigger the AMP as supposed. So confused!!!

I had RW bring his new 990 over and hook it up with my Sunfire Amps and he has the same problem. We couldn't get any sound from a digital or analog source. The only time we got any sound is when we hooked the main speaker feeds to the 7.1 inputs and we could play my analog connected MP3 player. Of course the MP3's volume control is the only thing that worked. I can't think of anything else that could be possibly wrong. It must just be defective out of the box. I am very interested in the 990. I am curious to see what Outlaw has to say about this.