Problem with startup - startup freezes

Hi, im new here. At first sorry for my English, im from another country, i hope to you understand me. Last time when I work on my MPC its working absolutely perfect until today. When I start up my MPC, its looks ok, its show "MPC500 startup" but then, screen remain blue. I shut down it and start up it again, and since the screen still remain blue, and it not show neither "MPC500 startup". I will be glad, if you can help me please.

it still looks like this and it dont want move from here. please help me:)

Hmm...

try factory reset:

1. Turn the MPC500 on while holding the [ERASE / UNDO] button.

2. Release the [ERASE / UNDO] button after the display shows [MPC500 (##MB installed)].

Afterwards (or if wasn't successful) download the latest OS from akai's site and place it on the CF (if possible)

Then follow these instructions:

>>>How to update MPC500

!!! NOTE: DO NOT SWITCH OFF THE MPC500 WHILE IT IS UPDATING THE OS !!!

1. Power the MPC OFF (leave the CF card in the MPC)
2. Press and hold down the [SHIFT] button on the MPC while, you power the MPC back ON (this will launch the OS Bootloader)
3. The MPC should show you a screen which reads:

New OS 1.13
OK(REC) or STOP

4. Press [REC]
5. The MPC should now start the OS update (it will first erase the Flash ROM and then write the new OS to Flash ROM)
6. Once the OS Update is complete, the MPC will automatically restart itself
7. Power OFF the MPC and wait 30 seconds
8. Power ON the MPC while holding down the [ERASE] button (this will reinitialize the MPC)

either cases are not working, it is show still only blue screen, nothing more.

bad RAM maybe. if you have the RAM expansion installed try to start the mpc without it.

i dont have installed RAM expansion. i have only the basic RAM.

check your cf reader. maybe some pins are bend. try booting without the cf card.

no, its not working. i try start it without CF card and it is the same like with CF card. when i push power switcher ON its still like on the photo, the display shows absolutely nothing.

ok i think my problem is solved. I try to turn the screw with name "CONTRAST" and it is suddenly working, but I never do nothing with it till now. thanks for you time guys.

Ah right yeah, 500 has the contrast pot. Didn't remember that one. Glad you worked it out.