I came across this problem today. Namely, that Philips TVs don't seem to get a good sync signal from some of the console cores. The most notables are SNES and Genesis. The Neo-Geo and Turbo Grafx cores (along with SMS I believe) don't have this issue.
Basically, it looks like Philips TVs are using a shade of black to differentiate the blanking signal, and the SNES/Genesis cores send this same level of black out as their normal bottom-level blacks. While this probably results in a better image overall, it makes it impossible for those cores to sync until a game fills the screen with a different color. Unfortunately, a *lot* of games on SNES and Genesis don't do this, and the core doesn't do this as well.
- Turning the Genesis "border" on fixes it for games that use anything but pure black as their border color as soon as that border appears (usually at title screens).
- Any Konami game fixes it when the background gets swapped for the white "flash" at the end of the Konami logo animation.
- Even "World of Illusion" fixed it with its slightly-grayer-than-black title screen border.