Why is my Sony Ericsson Xperia Play backlight not on when I go into gaming mode?

When I was sliding my screen up to use the PSP controls to play one of my games, the screen's backlight wouldn't turn on, nor show me anything other than a faint representation of what you would see on screen. In otherwords, I can barely make heads or tails of whatever I'm looking at like it were a GameBoy Color/GameBoy Advance LCD screen or a Nintendo DS without the backlight function on.

When I have the screen in full position(phone mode), the backlight is on and works 100%. It's just that I cannot see ANYTHING if I have the screen sliding up all the way to expose my gaming keys.

Another bit of info to know is that the backlight DOES turn on to show everything I've got if the screen isn't fully up, but nudged down a tad like you were sliding the screen back slowly before you put it back up(like a minor squeeze or slight grip with my hand). I had to mark where the screen is kept on and where it faults out with a Sharpie just to know where the light stays on and when it goes dim.

So right now, my cell is still functional, but not when the screen is all the exact way up. Just about 90% to 95% of the screen will be slide up to keep the backlight on, but at 100% up is when the backlight is KO'd. And because it's a PSP phone, it's going to be extremely difficult to see anything if I do play whatever games & emulators that are equipped for it. The touch screen function ALL WORK, but not the backlight if I have to go gamer mode on it. And to better detail what I meant by all that, the screen doesn't dim out if the edge is touching the borders above the Up button & Triangle button. Still exposed without being too covered up, but difficult to deal with if it comes to playing anything. So much so, I had to resort to using a rubber band to keep the screen from turning the backlight off.

Any ideas how to get this problem fix without dealing with third party bull crap?