white screen for my dreamcast

Hi, I have a dreamcast pulled out of the closet that power I see only white screen and nothing else. While the GD-ROM give a hint, but does not continue to load, I thought it was a graphics chip or other problem inherent in the video, but if you do not load the GD-ROM do not know what to think. No one knows this problem? Some idea?

 

I read something about the DAC chip, which needs to be replaced a few transistors, but I honestly do not know where to go; not counting that the console is not currently open. It 'a pal v1