PS1 / RGB / PAL GAMES / HORIZONTAL SHAKING

Hi guys. If I run PAL games on my NTSC PS1 - 7501 with official Sony RGB cable (euro. not JP 21pin) then the image is have horizontal shaking or black screen after start up (reset console fixed black screen but this is randomly). I connect console to LED TV with scart connector (european model). Any ideas? Maybe I need scart to hdmi converter?

PS: ntsc games work perfect.