OK, started this thread to assist a friend in fixing his PSP Slim.
Not sure on the PSP model, but it was one of the Darth Vader special editions(white).
Here's the story, he has it one day, drops it about 1 foot (What he told me).
Now the green light comes on, screen does not light up, no startup sound, UMD drive keeps trying to read the disc.
It won't shut off easily and requires you either to remove the battery or hold the switch for like 9 secs or more.

I've taken it apart, double checked all the conections, the boards seem intact as well as the CPU and WLAN chip. The UMD drive can move, it certainly seems to be working, and it can recognize when the hatch is open and if there is a disc inside.
It was sporting custom firmware, M33 (Not sure on the version, gotta check with him), I tried to see if it would allow me to access the recovery console, still no sound or response. Tried switching between 3 different batteries, 2 slim and 1 fat. No pandora batteries, I just temporarely exchanged the kernal in the battery with a magic memory stick and such to hack it(prievously).

Any suggestons, tips, advice, or simply if the thing just went belly up would be great to know.

Is the Screen Broken?

Can't say, can't tell. Screen does not light up, but the startup noise does not play either (it's not muted, volume to the max). I only rule out the screen atm because it can run without it and do the general startup procedure. Plus i don't see any damage along the screen's surface or anything, let alone a crack in the LCD pane (small thin piece of glass in which the image is constructed).

Loks like you might have a brick.

Very badly bricked PSP, i'll need a special pandora battery for this one if thats the case.

Wonder if i can resolve this with the magic memory stick solution.

Well Magic Mem Stick and Pandora's Battery go Hand In Hand.

It's not hard if you have an already hacked PSP.

Alrighty, it was bricked, as a pandora battery and magic memory stick allowed me to downgrade it to 1.50 M33 and it finally responded. I heard the Sony startup noise and I can hear it navigating the menu, but............The screen is basically dead, backlight is on but no picture.

My friend thanks me, but he does not have the money to buy a new one atm.
They like 45 dollars a piece on Ebay, surprisingly they did have slim psp screens.

Could you try to check the screen connection?

Found one a bit cheaper: http://www.dealextreme.com/details.dx/sku.12884

Hehe, didnt think anyone else would reply in this thread. My friend found himself a cheap replacement, a fat psp, he sorted wanted it more.

Does he want the cracked screen PSP slim? I do.