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Thread: Region Modded Genesis 50Hz output

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    Road Rasher superandroidtron's Avatar
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    Default Region Modded Genesis 50Hz output

    In preparation for an upcoming demoparty I help organize (shameless plug: http://www.demosplash.org), I'm trying to region mod our Sega Genesis so we can screen Overdrive 2, which is PAL only. This leaves us with the problem of video output. We have RGB cables and several video converters at our disposal including: XRGB-1, XRGB-2, XRGB-3, Framemeister, XPC-4, a GBS-8220 based device, and a mysterious box we acquired from Australia that seems to be able to convert PAL composite to NTSC.

    Does anyone know if any of these will be able to take the 50Hz RGB signal out of our modded Genesis and display it properly? We have previously displayed PAL Amiga/CPC/Atari demos on native hardware via the previously mentioned converters, but the fact that the Genesis is modded and has a crystal that does not run at the normal PAL colorburst frequency concerns me.

    Thanks!

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    Quote Originally Posted by superandroidtron View Post
    In preparation for an upcoming demoparty I help organize (shameless plug: http://www.demosplash.org), I'm trying to region mod our Sega Genesis so we can screen Overdrive 2, which is PAL only. This leaves us with the problem of video output. We have RGB cables and several video converters at our disposal including: XRGB-1, XRGB-2, XRGB-3, Framemeister, XPC-4, a GBS-8220 based device, and a mysterious box we acquired from Australia that seems to be able to convert PAL composite to NTSC.

    Does anyone know if any of these will be able to take the 50Hz RGB signal out of our modded Genesis and display it properly? We have previously displayed PAL Amiga/CPC/Atari demos on native hardware via the previously mentioned converters, but the fact that the Genesis is modded and has a crystal that does not run at the normal PAL colorburst frequency concerns me.

    Thanks!
    The Framemeister can be slightly awkward about out of spec inputs but will probably work okay since you're inputting RGB. How well will probably depend on your display's ability to sync to the out of spec signal - you may get slight stuttering.

    I've no experience of the other devices.

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    Wildside Expert fluxcore's Avatar
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    The GBS8x00 series sucks totally with 50Hz, don't think it will display at all.

    PAL60 is a reasonably supported 'thing' for TVs etc, but not sure if NTSC50 is (which would be your modded Genesis, I suppose).

    You're just gonna have to give it a go, I think!

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    Quote Originally Posted by fluxcore View Post
    The GBS8x00 series sucks totally with 50Hz, don't think it will display at all.

    PAL60 is a reasonably supported 'thing' for TVs etc, but not sure if NTSC50 is (which would be your modded Genesis, I suppose).

    You're just gonna have to give it a go, I think!
    There is no NTSC or PAL with RGB signal.

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    Mega Driven Raging in the Streets cleeg's Avatar
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    PAL is traditionally a 50Hz interlaced signal at its own specified resolution, the same is true for NTSC only at 60Hz. RGB is a method of transmitting that signal, to say that NTSC or PAL do not exist via RGB is not accurate as they do.

    PAL and NTSC are the standards, RGB (or composite, S video, component etc) is the method by which those standards are transmitted.

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    Quote Originally Posted by cleeg View Post
    PAL is traditionally a 50Hz interlaced signal at its own specified resolution, the same is true for NTSC only at 60Hz. RGB is a method of transmitting that signal, to say that NTSC or PAL do not exist via RGB is not accurate as they do.

    PAL and NTSC are the standards, RGB (or composite, S video, component etc) is the method by which those standards are transmitted.
    Incorrect.

    PAL and NTSC are video encoding methods and are used for video transmission via RF, composite video, and s-video.

    RGB has no encoding applied as it is direct and seperate signal for each colour.

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    Quote Originally Posted by CasetheCorvetteman View Post
    There is no NTSC or PAL with RGB signal.
    Did I say there was? OP specifically talks about a PAL to NTSC converter for composite signals.

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    Quote Originally Posted by fluxcore View Post
    Did I say there was? OP specifically talks about a PAL to NTSC converter for composite signals.
    He speaks a lot about having RGB cables and specifically, if any of the devices mensioned will take RGB at 50Hz from a Genesis console. View second paragraph in original post.

    The only mension of composite video is the box he aquired from here in Australia that converts PAL to NTSC via a composite input.

    The colour burst crystal wont affect RGB output, it is only functional on encoded signals, such as PAL and NTSC.

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    Technically speaking all that should be required to play the PAL region games that have been enhanced specifically for Euro region consoles is switch the console from 60Hz to 50Hz.

    No further mod should be required if this console is a Genesis, switching to 50Hz essentially makes the console a Euro Mega Drive as far as region locked carts and their functionality are concerned.

    If it was a Japan region Mega Drive, then the console may need a further mod to function in US/Euro mode, but in my experience with Asian version Golden Axe 3, the game operates fine on a PAL Euro region console, as the Asian Mega Drive is PAL, but with a Japan region instead of US/Euro. Switching the console to 60Hz stops the games starting, but not running.

    The only reason to swap out a colour burst crystal is if youre planning on using composite or s-video on a set that wont take PAL60. If using RGB, the colour burst crystal wont matter at all.

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    Quote Originally Posted by CasetheCorvetteman View Post
    Technically speaking all that should be required to play the PAL region games that have been enhanced specifically for Euro region consoles is switch the console from 60Hz to 50Hz.

    No further mod should be required if this console is a Genesis, switching to 50Hz essentially makes the console a Euro Mega Drive as far as region locked carts and their functionality are concerned.
    Okay, so how does one mod an NTSC US Genesis to output at 50hz? Because I've done the standard region mod on mine but it always outputs at 60hz regardless of which region it is set to. I've confirmed the region switching seems to work as I've used the 240p Test Suite and it does show the regions switch when I flip the switch. But the actual signal to the TV never changes and remains at 60hz the entire time.

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    Back then I modded my jp MD, and the 50hz signal I got was problematic, with unstable jumpy screen on many TVs. Genesis have the same crystal so results should be the same. Video monitors might cope better with it.

    By comparison, a 60hz modded euro MD never caused any trouble, if using RGB of course.

    All of this on CRTs.

    You know, the cheap SCART to HDMI that everyone deems crap, will actually output proper 60hz, even if the source is 50hz. You might get some blur and jitter, but IIRC Overdrive II doesn't use flicker shadows which is the most problematic thing with that converter.
    Gonna try in a sec.

    Ok it actually worked near perfectly. Anyone want infos ? or is it too late ?
    Last edited by Ryoandr; 11-15-2017 at 03:36 PM.

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    Quote Originally Posted by CrossBow View Post
    Okay, so how does one mod an NTSC US Genesis to output at 50hz? Because I've done the standard region mod on mine but it always outputs at 60hz regardless of which region it is set to. I've confirmed the region switching seems to work as I've used the 240p Test Suite and it does show the regions switch when I flip the switch. But the actual signal to the TV never changes and remains at 60hz the entire time.
    Its not the region mod you do to change output frequency, its the 50Hz/60Hz mod. The region swaps between Japan and US/Euro.

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    Mega Driven Raging in the Streets cleeg's Avatar
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    Quote Originally Posted by CasetheCorvetteman View Post
    Incorrect.

    PAL and NTSC are video encoding methods and are used for video transmission via RF, composite video, and s-video.

    RGB has no encoding applied as it is direct and seperate signal for each colour.
    Okay, so is it more correct to say that, in the case of MD / Gen RGB video signals that they are just RGB at 50 or 60Hz? And that said, 'true' PAL and NTSC signals only exist over those methods you listed? I like to have these things right!

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    Quote Originally Posted by cleeg View Post
    Okay, so is it more correct to say that, in the case of MD / Gen RGB video signals that they are just RGB at 50 or 60Hz? And that said, 'true' PAL and NTSC signals only exist over those methods you listed? I like to have these things right!
    That would be more correct yes. PAL colour encoding is superior to NTSC and typically gives a more accurate colour reproduction. This is why NTSC has tint adjustment and sometimes other functions that are not available on PAL, because theyre not required.

    When using RGB, there is no need for encoding to take place, none takes place, so unless the display device is really picky on source signal there should never be an issue with the frequency being slightly off.

    My main Mega Drive 2 console here is a Genesis, and it operates perfectly on both 50Hz and 60Hz with just the switch i have fitted for this purpose, including running with a Euro region Mega CD.

    Not all consoles put out a perfect 60Hz anyway, the NEO•GEO outputs 59.18Hz, but ive also seen them output as high as 61.82Hz too.

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    Road Rasher superandroidtron's Avatar
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    Thanks for the help, everyone! We ended up running out of time to apply the region mod, so we didn't get to screen OD2. We've acquired a PAL MD and after some testing, believe that the Framemeister and projector in the auditorium play nicely with each other at 50Hz.
    Last edited by superandroidtron; 12-19-2017 at 08:20 PM. Reason: punctuation

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