I found this surfing the net
These are simple, but good instructions on how to add a jap/US and PAL/NTSC (50/60 Hz) switch to any Genesis or Mega Drive model 1. That way, you can use ANY sega cd system (euro, US, jap) with it, as well as use any game (some newer games had country lockout). Also, the 50/60 Hz switch fixes the out-of-synch probs with FMV (i.e. Lunar) on european systems. You need a RGB Scart cable to get a picture in color on PAL TVs.
So all you need is a RGB-Cable and way you go