H320 comes on with white screen

[cu232]

Hi all,
my beloved H320 is sick! 
The player is in bonestock configuration, except Rockbox installed. No hardware mods.
Some days ago, he had turned off without any button pressed. While playing, hes shutted down.

Battery pack is fine, power is stable.

If you turn them one, a white screen will been appeared. No pixel cutouts, only white. HDD is running. If you connect them to a pc, you can read and write on hdd.

I guess, it will be a graphical problem.

Any help will be appreciated.

Thanks,
Steffen