During a discussion with my friend AJ while recording the intro/news bit for our Scene World Podcast, the idea grew to try to modify one of my PAL C64s to run into NTSC rather than going the expensive and complex way of getting one shipped from USA.
It’s not that complex, here is what you need.
- Get a GSG8701-replacement clock generator IC. There are at the time of writing this two known options for me: The one from Jens Schoenfeld or eslapion, while the one from Jens has the advantage that you can get a version that has a jumper to switch the clock between NTSC & PAL.
- You need an NTSC VIC. Careful: Make sure that you use the model with the correct voltage or else you will fry your VIC IC! Use Wikipedia as reference mine is ASSY 250425 So I have got a MOS Technology 6567 – VIC II which is the NTSC version – Originally it had a 6569 inside (PAL).
I removed the jumper of the Jens Schoenfeld clock generator replacement IC to put it to the NTSC mode.
Here you can see, it works! This plays Grand Prix Circuit in its NTSC version in the real speed and not 25% as it would be on an European machine!
https://www.facebook.com/nafcom/videos/10155800598785971/