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Sega Mega Drive Clone - Region Switch Mod

Posted: Sun Jul 24, 2022 12:22 pm
by sdm
I have a Sega Mega Drive "MEGAGAME" clone. I wonder if it is possible to install a PAL / NTSC switch? I found three pins "J1" marked P and N (Pal / Ntsc?), But I'm not sure if they are responsible for changing the region. Has anyone had / has such a clone and knows anything more about it?

Video:
https://www.youtube.com/watch?v=NBiySZepNdQ

I wonder why the original Aladdin PAL does not work and displays the message "developed for use only with PAL & French Secam Mega Drive Systems", while Aladdin NTSC (USA) displays "developed for use only with NTSC genesis Systems" (which is logical, because the console is the PAL version). Two other PAL games I have, The Lion King and Sonic 1, are working.

Re: Sega Mega Drive Clone - Region Switch Mod

Posted: Mon Jul 25, 2022 2:05 am
by TmEE
J3 is video output 50/60Hz setting
J1 is Region register PAL/NTSC setting (has nothing to do with video output)
Japan/Export is unavailable, but it is done by PCS8492 pin 72 (GND=Japan, VCC=Export).

VDP (PCS8391) seems to be a bit modified compared to normal superclone VDP, it seems to take a crystal instead of oscillator and there are those JS0...3 jumpers which function I do not know.

Re: Sega Mega Drive Clone - Region Switch Mod

Posted: Mon Jul 25, 2022 12:49 pm
by sdm
Thanks. I'll check these jumpers.

Re: Sega Mega Drive Clone - Region Switch Mod

Posted: Wed Jul 27, 2022 2:52 am
by TmEE
With luck, SW4 in top right corner connects to the JP/EN pin, in some machines that is where region setting switches are exposed.

Re: Sega Mega Drive Clone - Region Switch Mod

Posted: Tue Aug 09, 2022 8:01 am
by sdm
I have another SMD clone. I can see 5 jumpers: J1, J3 and a set of three jumpers next to the large heat sink. I understand that the console is set to 50hz by default but with the USA / NTSC region?

As in the first case, Aladdin PAL does not work on it.

Re: Sega Mega Drive Clone - Region Switch Mod

Posted: Tue Aug 09, 2022 12:40 pm
by TmEE
That's a "standard" superclone where all chips are pin compatibles of original Sega chips (made by UMC with better process than Japanese and overclock lot better lol).

Jumpers near the encoder chip only control encoder itself and won't affect the region setting or frame rate itself. You choose if the encoder is in PAL or NTSC mode and if it gets subcarrier from unpopulated cystal or from VDPs own signal. These vary slightly from model to model

J1 is PAL/NTSC region setting for IO chip and J3 is 50/60Hz setting of VDP (actual frame rate control). Japan/English setting comes from the same pin on SE94 as other machine (72).

Re: Sega Mega Drive Clone - Region Switch Mod

Posted: Tue Aug 09, 2022 3:15 pm
by sdm
Thanks. So it is similar.
In the first clone after loading the game with Genesis, I had a message about an incompatible game region, while in this console I only have a black screen.

Re: Sega Mega Drive Clone - Region Switch Mod

Posted: Tue Aug 09, 2022 3:40 pm
by lidnariq
Can you easily make/run a copy of the 240p test suite? It should tell you how the jumpers are wired.