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Sunday, May 23, 2010

Hacking the MGCD (Part 1)


The MGCD is a console to JAMMA converter created by Taiwanese company Frolicker, and distributed by many Taiwanese arcade resellers. Several versions of the MGCD were produced for Dreamcast, Playstation2, Gamecube, and Xbox. What makes the MGCD unique to other pay-to-play console timer PCBs, was the MGCD could be programed to recognize the start game screen of a particular title, as well as the end game screen, allowing it to disable all input, sound, and even video, until the game was fully loaded and start game screen ready. So in a sense, the MGCD could disguise the fact that you were playing the console version of an arcade game. Here is the manual for the MGCD-B Version, showing all the nifty features and settings.

For a pretty stupid reason, the MGCD isn't exactly plug and play with most JAMMA setups. The problem is in the fact that the MGCD maps 12 player action buttons to the jamma finger board, utilizing the last 2 pins on each side, which are typically tied to ground on most JAMMA looms. If these connections are tied to ground, the MGCD will not boot up properly, and simply not work. To get around this, you must either modify your JAMMA loom connector of your cabinet, detaching the ground wires to these last pins, and connecting them to player buttons 5 & 6, or just leave them off completely. So instead of modifying my cabinet, I just created a fingerboard which lifts these last two pins on each side, allowing me to play on any JAMMA cab. If I wanted to use these last two buttons for fighting games, I could simply run a wire to the fingerboard up to the control panel.


Leave the last two pins on either side disconnected.


Similar to other pay-for-play "timer" PCBs, the MGCD can also play credits for time, although with an annoying timer countdown that is displayed once per minute at the bottom of the screen. With the limited number of games recognized by the MGCD firmware, the timer feature is primarily used by most people, where you can setup a single credit to play for a maximum of 256 minutes. The problem, of course, is that that annoying time displayed at the bottom of the screen.



Figuring out how to remove the timer overlay took some trial and error. At first I tried re-routing the RGB video signal from the console output, directly to the front of the fingerboard. This did work, but the signal was unamplified, and too dark/weak to be displayed on an arcade monitor. So the only other option was to figure out which chip on the MGCD was doing the video overlay, and disabling it. This took a lot of probing around, but eventually I found the chip, and grounded one of the legs to effectively disable it.


Video timer overlay chip highlighted in red.



Connecting these two pins (highlighted in red) will disable the video timer overlay.


Now here is what the output looks like without the timer.



Finally, here is the MGCD installed on my PS2, and ready to be played on any JAMMA machine.




Next, I'll talk about how to take the MGCD Dreamcast version and hook it up to a cabinet at either 15khz or 31khz. (Go to Part 2 here!)

20 comments:

  1. Hi,

    Where did you get the MGCD?...Can you set this up to play for credits ( Like the Arcade PCB ) or is it only timer.. Thanks.

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  2. I bought mine a long time ago from cosmicco or excellencom (forget which), but they don't sell them anymore. They do pop up occasionally on neo-geo forum and ebay.

    To answer your second question, yes the MGCD can be setup to play for credits, although you have to look at the Manual I linked in the article which lists all the games its compatible with for credits. Otherwise credits for time is universal to any game.

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  3. Hi! i have 2 MGCD interfaces exclusively made for Dreamcast in a Capcom VS SNK box, just like yours. Now, i know that changing dipswitches can get other games to work ... but what do i need to make PlayStation2 console to work with my MGCD interface? Where lies the diference between Dreamcast version and Playstation2 version?

    Just thinking if i would be able to change the joystick plugs?

    I will be so thankfull if you can help me to clear this doubt
    greetings from Argentina!

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  4. Hi Jorge! From a hardware standpoint, the two MGCDs are identical. Obviously the connectors are wired differently for the controllers and AV. Unfortunately the two chips with labels on them are also different. It says PS2 on both the chips for the Playstation2 MGCD. It makes sense as this is what would need to decode the joystick protocol for PS2 versus Dreamcast.

    These chips look like custom programmed ICs, not EPROMs so you will not be able to burn your own set.

    But there may still be a solution! If you set the dip switches to 256 minutes play per coin, and use a Dreamcast to PS2 controller adapter, this could work with a PS2. You'll have to hack an RGB scart cable to the AV connector similar to how I did it my blog entry. You just need to figure out which is R/G/B/Gnd/Sync.

    Let me know if this makes sense.

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  5. After reading your answer I started searching, checking and learning everything about MGCDs and DreamCast motherboard (video output mostly) anyway i have to weld R,G,B, Sync & ground (16;15;14;10;1) from the motherboard of my DreamCast to the MGCD AV because one of the interfaces brought no AV wiring. And the original AV of the DC uses the 1#;2#;3# and 13#(M GCD doesn't read Composite video) the other pins are not present in the video plug. (I am just telling this detailed stuff to make clear for myself and to make others understand as well as i do now... well...
    I can't express how gratefull I am after read all your posts about hacking/modding and improving Video consoles into arcade interfaces!
    I spent last 12 years playing, welding, improving, adapting, just for fun and enjoyment modding hacking and improving arcades and consoles but really needed a big hand with this system. since i just started with 100% arcade systems

    (taking out the mgcd video overlay is glorius ;D

    About the solutions you suggested me: I realise the chip diferences on both boards. and really stop wanting to make it work with ps2 for two reasons: First: I really want ps2 games to work with coins/credits, (exclusive fighting games) not time.
    and 2nd: If there is a DC to PS2 plug adapter please tell me where to get ones ;) (never saw! not even in pictures)
    Muchas Gracias! ;D (more questions coming xD)

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  6. Hi Jorge, ebay has Dreamcast RGB and SCART cables which will have all the connections you need for the MGCD.

    Unfortunately I could not find a Dreamcast to PS2/PSX controller converter. Seems there are plenty of converters which work the opposite way, from PS2 to Dreamcast, this is not what you want. Have to keep checking ebay for this.

    Best of luck!

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  7. Hi all im from australia and am trying to set up mgcd with my original xbox to use with an old scud race driving cabinet so i have rewired everything in jamma and have plugged the board in i however am trying not to use the on board video rather just pluging the svideo and audio from the xbox directly to my lcd screen.

    i cant get it to work i have 5 v on all my buttonas and when i press a button the voltage drops to zero however i cant credit or anything and nothing works is this because it needs the video through the board and if this is the case will shorting the pins on the chip as pictured above fix my problem
    thanks Pat

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  8. Hi Pat, first I assume you are using the XBOX version of the MGCD. Second, you are correct in that the MGCD will not work unless video is hooked up to the board...specifically the video sync. This is why I had to hack my Dreamcast version (in Part 2 of this article) to hook the video up to the inputs on the MGCD, while using the VGA output from directly from the dreamcast to my monitor.

    Shorting out those two pins will only disable the video counter overlay, it will not fix this problem you are having. You will need to split off the video wires going into the MGCD to hook up to your monitor. I suggest you follow what I did on my Dreamcast version, and solder a second connection to the underside of the MGCD video connector and run that to your LCD monitor.

    Good luck! Sounds like a fun project for a driving cab.

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  9. thanks for your fast response arcade fever i will give it a go and let you know how i go
    regards Pat

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  10. Hi arcade fever
    i have finally made some progress with my mgcd in a driving cabinet with xbox.

    However for some reason not all my games display on the screen i have used the output rgb and sync of the jamma loom into a converter board that converts and outputs the signal in vga to my lcd screen

    i have played around with all settings on the xbox and on the converter board and i just cant get certain games to play the screen just displays random frozen part images that are sometimes repeated from left to right of screen and also top too bottom
    do you have any ideas of what the issue might be for eg i can play rally sport challenge 1 and 2 and nfs underground 2 but not nfs hot pursuit or even forza
    your help would be greatly appreciated regards
    Pat

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  11. Hey Pat, this is a difficult problem to solve as older LCD screens are very fickle about what input resolutions it will display. You need to find out what the "native resolution" of the LCD monitor is, and set your converter board to only that resolution (and make sure its at 60hz). Most older monitors have 1024x768 as their standard pixel-for-pixel native resolution, so start there.

    Lastly, I've herd of many people having problems with cheap upscaler boards not working on their LCD monitors...its a very common problem unfortunately. My only suggestion would be to install a CRT monitor in the cab.

    Sorry, wish I had better news. Good luck with the project!

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  12. thanks again for your advise the lcd is definatley 60 hz and my upscaler board is from jamma boards website i am wondering what would happen if i spliced the video at the input of the mgcd board and rather than using the crt output coming from the jamma loom i go directly to the lcd (splicing the input)there for mgcd is happy as it still gets a video signal and lcd is happy because it thinks it is connected directly to the xbox

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  13. Yes, that does sound like a good idea! You should confirm that the scale is compatible with your monitor by hooking xbox -> scaler -> monitor just to test (without the MGCD). If that works fine for all your games, then do as you said and splice from the MGCD input (as MGCD still requires sync to function properly).

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  14. Do you happen to know what the video input to the mgcd from the xbox is? from the research ive done it appears as though its R G B and composite

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  15. Yes, it looks like R, G, B, CompSync, GND, AudioL, AudioR.

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  16. Hi arcade fever thanks for all your help my driving cab is now working perfectly i managed to find the composite video and spliced it from the input directly to my lcd tv everything works perfectly now and the best thing of all is i dont have to worry about seeing that stupid clock lol
    just wanted to say thanks again

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  17. hi there. im giving this a shot maybe u can shed some light on my problem.

    i got a house of dead 3 arcade cabinet, running a xbox with a mgcd. when i got the arcade it was working fine, as in u throw in the credit and once u die the game is over...i believe they call this "credit/round mode". then all of sudden the xbox hard drive just died :( i had no idea how to fix it, so onto the internet i went. figured out how to make a new hard drive for it with a cable i made and dumping the firmware etc.
    in the end i got house of the dead 3 on the xbox again to run. but for some reason no matter what i do i cant for the life of me get it to work in the same way, only timed mode works?
    i even emailed the guys who make it asking for some help, but u know how helpfull they can be. this guy gave me some type of cd that has a loader for the game and well i put it on the hard drive, but alas still the same problem, cant get it to go into "credit/round" mode.this loader is basically just so that when u turn on the xbox , the mgcd sends a command pressing i think its "a" twice to load the game. i figured this loader might have helped but nada... ill note that when i originaly got the game there was no loader loading when i started it, it went straight to the game... but i have done that method also.
    the guy said the unit might be broken, but only the xbox drive died so i dont believe thats the case.

    the unit i have is made by twe. the lable on the one rom says hod-01. no matter if i switch the unit to be 00 or 01 , that number just stays on the screen the whole time and should go away i believe when it picks up the game (the number is for xbox version as in one thats made before 2003 and one after). i believe its not picking up the game from the looks of it, throwing in credits does nothing. if i switch to time mode, i can play , but obviously i dont want it like that.
    i even dumped the rom to maybe see if i can spot something in the code via hex, but cant really make out too much :(

    i tried usa and eur versions of the game, but still does the same.

    u perhaps have any ideas?

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    1. Sounds like this was a particular setup. When the drive failed, you said you were able to dump the entire contents of the disk and rebuild on a new drive? It sounds to me like it was a modified version of HOD and not retail, to work specifically with the MGCD. But I could be wrong as the MGCD is supposed to work with all the retail games...you just need to put in the correct dip switch settings. I'd suggest downloading the xbox MGCD manual, and confirm the dip settings is correct for retail HOD disk.

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  18. hi, with mgccd i can boot all the games i want and not only jap games if i set it to all 1 on 8dipswitch?

    and you have the pinout of the video cable so i can hack it to a ps2?

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    Replies
    1. Not sure what you mean by "boot all games". This doesn't help booting different region games on a Dreamcast. There a bios hacks you can do to change your dreamcast region (google search should find them).

      You can't hack a Dreamcast MGCD to run on a PS2. You might be able to get the video to work, but the controls won't work. That said, if you wanted to hack the video, its pretty straight forward red/green/blue/ground/horizontal sync/vertical sync.

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