[Dreamcast] Why my O/C @240MHz doesn't works ???

[localheureux]

Hi,

I try to overclock my DC@240MHz like this: (note  PAL Dreamcast revision 1)
http://www.racketboy.com/retro/2005/11/overclock-your-dreamcast.html
I used a 40MHz Kyocera KX0-01 crystal with (officialy) standard pinouts.
But  it doesn't works, no image appears I have a "beautiful" black screen and no sound, but I hear access disc sounds.


I didn't saw (in the tuto above) "...but only when outputting to a VGA or suitable RBG monitor, due to the increasing refresh rate."
So I made a VGA ouput like this:
http://artofwar.free.fr/images_site/dossier/VGA%20Dreamcast/vgadcoc0.jpg
In standard mode (200MHz) it works, I have image on my VGA monitor and sound to an ampli.
But at 240Mhz it still the same, no image and no sound at all but disc turns and I hear access disc sounds.


I checked all, all removed and remade.... It still the same, I don't understand where is the problem and begin to be bored....
Help..... thanks.