I recently purchased a digitizer fully assembled on ebay and to my luck didn't work. I contaced the seller and he gave me...

I'm having problems with my glx1200h head amp. When I connect it to my speakers to play, the sound no longer projects...

^ you might have not have done it correctly. Make sure you didn't leave any residue around the components. It can cause faulty things to happen.

Considering he says the screen doesn't show anything, it could also be the screen that got damaged. You should try pluggig in into a computer the previous poster has mentioned. If you get it to read, then it could be a screen problem. Which would indicate why it isn't turning on.