Problem with PC Engine CoreGrafx. Can anyone help?

[Alter]

I bought CoreGrafx and some reason that systems AV output was been replaced with a RF unit. I couldn't get any picture out with a RF-cable so I did replaced it with 5 pin DIN connector and I did check here where to solder those pins correctly. So now on I can plug it to my TV with a AV-cable, but I just got picture with no colours (white and black) nor sound. And also picture waves.

Could it be that my TV cannot handle NTSC signal or is the system itself somehow screwed up?

[J0e Musashi]

Sounds like someone swapped the internals between a PCE and a CoreGrafx to me. Can't really offer much help based on what you've given so far. It could be anything.