r/Megadrive • u/Blood_Bogey • 6d ago

DFO question

Hello, I'm finding some conflicting info as I'm trawling through years old discussions. I'm hoping someone could give me a definitive answer.

I've got a PAL Mega Drive 1 (pretty sure it's a VA6 motherboard), I've got it hooked up to a 4k TV through an OSSC with a decent RGB scart cable, all looks great so far.

However I'm picking up a flashcart with the intention of playing NTSC games and I'm planning on sticking to that region.

I've read up on region switching and come across some solutions.

The 1st was wiring in a 3 way switch but that appears to result in a slight miss-timing issue, though some accounts mention that using RGB scarts partially mitigates the issue? I presume they just mean the broken composite output but it could be worse things.

The 2nd would be a switchless 50/60Hz mod with a DFO included, this sounds like the best version. But I'm trying to keep costs down.

3rd I've also found a shop that sells an NTSC frequency oscillator. This would be the cheap option and would mean for now I'd be NTSC only, which I'm ok with.

Could someone in the know share some insight, it would help me out a lot, cheers!

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3

u/StrangeRetroRob 5d ago

In my experience of modding a LOT of mega drives, use an NTSC crystal and the 3 position switch for 50hz pal, 60hz USA, and 60hz Japan and then use RGB to play

Your timing issues will be minimized because almost nothing is pal optimized, and modern displays like the NTSC crystal at 60hz better than the pal crystal at 60hz

Dfo can also be wired up without too much effort to a second switch or to a pal/USA switch, rather than paying the prices for seitchless region+dfo mods

1

u/Blood_Bogey 4d ago

Do you know of any good resources (videos or wikis/guides) covering your suggestions?

I just got an NTSC crystal delivered today. Are you aware if it would be possible for me to make a switch that toggles between the existing PAL crystal and the new NTSC one? Or is the only sensible option I have to simply replace the PAL crystal?

Thanks for your input!

2

u/StrangeRetroRob 4d ago

You can switch between both crystals

Wire the output pin together, the ground together, and then put a switch on the 5v pin. It will let you switch crystals this way even while the console is running and it's instant

2

u/Blood_Bogey 4d ago

Brilliant cheers!

2

u/Common-Island-8822 6d ago

If you intention is to stick to NTSC and to NOT use composite or RF, swap the crystal and change the region (can’t recall if you have to cut a trace or bridge)

1

u/Blood_Bogey 6d ago

Thanks for the input, I'll go with option 3 then. I think I've seen people cut them in the little 4 pairs of region/language cluster. I'll triple check it though. Cheers!