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Thread: Bad geometry only with MVS board?

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    Bad geometry only with MVS board?

    Hi all,

    I have one TV Sony KV-21M3A (BE-4A chassis) where I have connected all my retro consoles (Mega Drive, Saturn, Dreamcast, PS2), and very recently I have connected also my supergun. All of them use RGB cables.

    So, until I have connected my MVS MV1A board to the Tv, I have never realized overscan/bad geometry on any console. But when I'm trying to play NeoGeo games, that is really very notorious. So I thought I should see a crosshatch picture and then compare. In the following link there are 2 different crosshatches, one with Sega MegaDrive (Genesis) picture, and the other with MV1A board. https://imgur.com/a/SNnHD4n

    As the Mega Drive geometry is not perfect (in the games I can't even notice), the NeoGeo is very obvious (and in the games is heavily noticeable as in some games I can't even see the credits numbers).

    Why does this happen? Is there any way to solve this? I really don't want to everytime I use the MVS board to go to the Service Menu and configure for the MVS board, and if I want to play a little PS2 I will have to go to the service menu again and change it back to where it was in the first place.

    Shouldn't the pictures be at least approximately the same? I only have issues with the MVS board

    Some help? Thanks!

  2. #2
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    I don't see any actual geometry problems, just overscan issues. This is just how the neo-geo operates. It was designed as an arcade board first where monitor adjustments are easily accessible and left that way for extended periods of time until the entire pcb was changed to a different game.

    SNK tried to institute tile safe areas (the white sections) to accommodate the varying degrees of overscan a tv might exhibit. Some developers ignored this and put game relevant graphics in the overscan area anyway. You are just going to have to live with the fact that the tv will be adjusted every time or graphics will get cut off.

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    Dear Shadownkn55,

    Thank you for your reply. Yes, where you read bad geometry it should be only overscan issue.
    Well, reading your reply I was both happy and sad at the same time. Happy, because I was thinking my board may have some issue and could be somehow defective even though I don't get any problem playing the games apart from the overscan issue. Sad because its a pain in the ass to be constantly accessing the TV Service Menu and set the picture correct just to play NeoGeo.

    Sometimes I get off the work and just want to play 20min or something, if NeoGeo is the platform chosen, half of that time will be accessing and configuring the Service Menu.

    Is there any solution, anything than could help solve this? Is there any adapter, any gadget to configure the TV Picture without accessing the Service Menu?

    Thank you so much

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    Yeah there is a solution for it. I haven't tested these but people usually use an extron or one of these

    https://www.aliexpress.com/item/4000...archweb201603_
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    That only adjusts the position of the video signal. Sounds more like he wants to resize it in addition to repositioning.

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    Quote Originally Posted by ChuChu Flamingo View Post
    Yeah there is a solution for it. I haven't tested these but people usually use an extron or one of these

    https://www.aliexpress.com/item/4000...archweb201603_
    Thank you so much! That's really a neat device! But as @shadowkn55 said, that device only adjusts the Horizontal and Vertical picture position. As you can see in my case, that wouldn't help me much since I needed to shrink the picture also a little bit.
    Is there any device just like that but as well as adjusting the position of the picture it also adjusts the Horizontal and Vertical size of the picture?

    Thanks

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    Im not aware of any device like that, maybe Fudoh from shmups.org knows. Ones that do usually have a frame buffer afaik and will introduce lag.

    For most games if you adjust your screen to 256x224 or 320x224 on something like a dot cross hatch pattern (like the one from the 240p test suite and your pictures) its about the best you will get.

    Your best bet would be to find a analog monitor with V/H size/position pots so you can adjust on the fly (like PVMs), compromise and live with it by adjusting to fit both Genesis and Neo-Geo, or play play on a flat screen.

    Having those vertical and horizontal size/position is one major reason I love my arcade cabinet.
    Last edited by ChuChu Flamingo; 06-07-2020 at 01:38 PM.
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    EDIT: Sorry, can't read for shit, going back to sleep now

    (you already tried the service menu)
    Last edited by CORY; 06-07-2020 at 01:50 PM.

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    Quote Originally Posted by ChuChu Flamingo View Post
    Im not aware of any device like that, maybe Fudoh from shmups.org knows. Ones that do usually have a frame buffer afaik and will introduce lag.

    For most games if you adjust your screen to 256x224 or 320x224 on something like a dot cross hatch pattern (like the one from the 240p test suite and your pictures) its about the best you will get.

    Your best bet would be to find a analog monitor with V/H size/position pots so you can adjust on the fly (like PVMs), compromise and live with it by adjusting to fit both Genesis and Neo-Geo, or play play on a flat screen.

    Having those vertical and horizontal size/position is one major reason I love my arcade cabinet.
    Thanks for your reply!

    Well, yes.. It's a LOT easier to adjust those kind of settings in a arcade cabinet!
    I will try to get in contact with Fudoh, but I'm starting to think that I should go to a different solution. One dedicated CRT TV just for my supergun. By "analog monitor" you are referring to one CRT Computer monitor? Don't know any model that has those pots to adjust the settings. Can you confirm that you are referring to those? That would help me a lot! I think it might be easier and cheaper to find then one CRT TV.

    Thanks!

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    Mostly im talking about professional grade monitors like the Sony PVMs and other pro grade monitors. Computer monitors can adjust their vertical and horizontal positions + size but most don't accept 240p directly so you would need a line doubler like an OSSC/Framemeister/Retrotink.
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    Quote Originally Posted by ChuChu Flamingo View Post
    Mostly im talking about professional grade monitors like the Sony PVMs and other pro grade monitors. Computer monitors can adjust their vertical and horizontal positions + size but most don't accept 240p directly so you would need a line doubler like an OSSC/Framemeister/Retrotink.
    Thanks for your reply.
    Oh, I see! Well, PVMs or BVMs are very hard to find. I have been searching for one for a long time. Everytime I see one, they ask a kidney for it

    I guess my easier and cheaper solution is one dedicated CRT TV. I need to start searching for one!

    Thanks for your help!

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