I'm new to the PC engine, I was given the coregrafx I have some time ago but have just got round to having a look at it. I was told at the time that it had been modified, and that they had only been warned away from the person who did the mods after they got the system back.
SO I didn't really expect it to work, but it does (sort of). The video output does seem to be RGB and the whole thing works fine if I use an everdrive.
However it won't boot from a normal game card, I have tried 5 so far and they all just give a purple screen. I was told that it had some sort of region mod but there is no visible switch so I'm not sure if it does or not.
I have tried a few things I read on other threads such as cleaning the cartridges with isopropanol and trying to back them out a little but nothing works. The everdrive does also give a purple screen for a few seconds before booting to the menu, I'm not sure if that is normal behaviour .