Sega Mega Drive Clone - Region Switch Mod

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sdm
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Sega Mega Drive Clone - Region Switch Mod

Post 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.
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P1110580.MP4_snapshot_00.00_[2022.07.22_23.54.09].jpg
P1110580.MP4_snapshot_00.02_[2022.07.22_23.54.22].jpg
P1110580.MP4_snapshot_00.06_[2022.07.22_23.53.58].jpg
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TmEE
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Re: Sega Mega Drive Clone - Region Switch Mod

Post 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.
sdm
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by sdm »

Thanks. I'll check these jumpers.
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TmEE
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Re: Sega Mega Drive Clone - Region Switch Mod

Post 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.
sdm
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Re: Sega Mega Drive Clone - Region Switch Mod

Post 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.
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TmEE
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Re: Sega Mega Drive Clone - Region Switch Mod

Post 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).
sdm
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Re: Sega Mega Drive Clone - Region Switch Mod

Post 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.
lidnariq
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by lidnariq »

Can you easily make/run a copy of the 240p test suite? It should tell you how the jumpers are wired.
sdm
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by sdm »

Unfortunately, I don't have any flash carts. I changed the J1 and J3 connections to N and now the image is in 60hz, but unfortunately games from Sega Genesis (Aladdin USA) still display information about the wrong console region. Other games like Lion King PAL and Sonic The Hedgehog PAL started and run at 60hz.

However, changing J1 / J3 to N in MEGAGAME did not change anything - the signal is still 50hz.

I wonder if it is possible to configure these clones for full Genesis NTSC compatibility?
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Fisher
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by Fisher »

I took a look and found that I had a similar clone.
Unfortunately, I couldn't find a better picture of the region mod.
SE-94 US/JP mod
SE-94 US/JP mod
This PCB had a switch soldered onboard which changed the region.
When I removed it, the pin broke apart and I had to do that "grinding" on the chip.
The wire is plugged into the reset pin.
Since most of the time the region is checked only on bootup I only have to hold reset when powering on the console and I get the JP-only games to boot.
I hope this helps.
I'll try to find a better picture, or locate the console and take some better ones.
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TmEE
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by TmEE »

Pin72 on SE-94 is the JP/EN setting and it is usually hardwired and not exposed to anything on most machines I see (so pin lift or chip removal+trace cutting is necessary). On few I do see it as a jumper pad.
sdm
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by sdm »

Pin72 on SE-94 is connected to 71 and 70 together. Does it matter?
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TmEE
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by TmEE »

It just happened to be a convenient location for GND/VCC, in any case you have to isolate the pin from everything else in order to change the JP/EN region setting.
sdm
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by sdm »

I wonder if it is possible to modify any of these clones to output the RBG signal?
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TmEE
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Re: Sega Mega Drive Clone - Region Switch Mod

Post by TmEE »

One with SE-93 VDP certainly is, you only have to put the DIN8 in place of DIN5 and it should work fine.
The other with only RCAs may be a tougher problem. It has changes done to VDP so it can output native CVBS signal and it is not unlikely that RGB pins have been repurposed for that. I don't have such a clone to play with so I have no further info...
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