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making supergun jamma power signal ect

Discussion in 'General Tech Help & CD Burning Help' started by Xavier, Feb 27, 2002.

  1. Xavier

    Xavier Mid Boss

    in the document i have it talks about using computer power cord to power the jamma , unfortunatley I think that there using a euro pc cord because mine only has 3 + - and ground in it ..ive cut open 2 and both the same way

    also he says that rgb isnt compat ible with vga because they use diffrent power freq .

    Unfortunatley i live in america and rgb and scart arnt an option .

    i would like to convert the rgb to vga first , then converting to ntsc rca coax whatever will be simple .
     
  2. Xavier

    Xavier Mid Boss

  3. ExCyber

    ExCyber Staff Member

    Erm... not sure what you're trying to do exactly, but a JAMMA board will use DC, not AC. I'm pretty sure a PC power supply will work for JAMMA, though I don't remember the exact voltages.

    Also, with that diagram... I'm not sure what the standards are for arcade power supplies, but I'd sure be pissed if my PC power supply had no filtering or overcurrent protection...
     
  4. Xavier

    Xavier Mid Boss

    what exactly that im tring to do is build a sugergun from scratch , I found an old ibm svga moniter by the dumpster ...the tube was broke , but i belive it has all the neccesary parts i need except a jamma connector and maybe a scrapboard or 2 and it would make a cool house built in speakers/sub and everything .

    The pc power cords i cut only have 3 cords inside green black and white . and the plug in only has three points .

    i I

    I

    I know the neccesary voltage i need getting it to that is another story .
     
  5. IceDigger

    IceDigger Founder Staff Member

    uhm.. that's cause there are never more than 3 lines for power, wtf do you want with more? are you trying to hook up the board straight to 110 V or something?

    a normal AT PC power supply will work, a VGA monitor however will NOT, unless you pay for a RGB->VGA converter, which isn't cheap.

    "i would like to convert the rgb to vga first , then converting to ntsc rca coax whatever will be simple ."

    that'd easily cost you 3x as much as directly getting a rgb->ntsc converter, and you'd lose more picture quality that way too.
     
  6. Xavier

    Xavier Mid Boss

    yes i want to directly power the board , the schematics for homemade ones that i found show something like 4 or five coming out of the cable ...except to the link that i supplied
     
  7. Xavier

    Xavier Mid Boss

    thats fine

    do you think you can make one yourself i you had the right stuff ? Looking at the picture at this websight it does

    http://www.jrok.com/hardware/RGB.html

    except what the chip on the bottom
     
  8. Xavier

    Xavier Mid Boss

  9. IceDigger

    IceDigger Founder Staff Member

    you can't simply hook up a vga->rgb converter "backwards". that won't work.

    you have to use a pc or arcade power supply in between, "direct" powering won't work.
     
  10. Xavier

    Xavier Mid Boss

    So whats a way to connect this to anamerican television (somthing you can make) rf rca vga ect

    The reason I like vga is because I have one of these

    http://www.focusinfo.com/products/tview_microxga/tview_microxga.htm

    Also I ripped the vga connector out of the monitor and it has real convienent connectors .

    Btx Akron Megadrive controllers can have 7 buttons on them .
     
  11. Xavier

    Xavier Mid Boss

    or svideo also
     
  12. ExCyber

    ExCyber Staff Member

    There are numerous integrated RGB to NTSC/S-Video encoders, such as the Analog Devices AD722/724/725.

    You cant really make them as such, but they could be integrated into your JAMMA rig. There's almost certianly a way to make a homebrew encoding circuit (after all, they had to do this stuff for live NTSC broadcasts before integrated circuits really took off), but the quality/cost/size tradeoffs might suck.
     
  13. Xavier

    Xavier Mid Boss

    Oh yes if those are pdf documents ive found them already ..at least one of them and yeah like you said there some things in there that i cant replicicate , also I believe that theres some unneccisary parts in them . (for formats other than ntsc)I'll need to read through them a couple hundered more times to figure out whats what .

    (Edited by Xavier at 5:55 am on Mar. 4, 2002)
     
  14. ExCyber

    ExCyber Staff Member

    I'm generallly pretty lost when it comes to analog electronics, but I think RGB to YIQ conversion could be done with some op amps. I haven't seen any info on how to go from YIQ to S-Video. I also don't have any good info on how to encode the sync in the Y channel, but I'm pretty sure it involves pulling it to a "sub-zero" (i.e. blacker than black) brightness level.
     
  15. IceDigger

    IceDigger Founder Staff Member

    you can go straight from rgb to s-video with the AD 724, and prolly the other 2 as well.
     
  16. ExCyber

    ExCyber Staff Member

    Yeah, they all have luma/chroma outputs. They don't go straight from RGB to S-Video though - they convert the RGB to YUV internally, then convert that to S-Video, which apparently involves adding the color subcarrier frequency and combining the U and V signals such that they're out of phase with each other. I only mentioned using op amps to do RGB to YIQ/YUV conversion because Xavier seemed to be interested in having a bit more control over the conversion hardware...

    As for the six-button MD controllers, it's probably a bit of a pain in the ass to adapt them to the raw signals needed for JAMMA, but I think it wouldn't be too tough with a microcontroller, assuming you can find one with enough I/O pins (I think you'd need 18 I/O pins per controller). Or you could do things The Arakon Way[TM] and simply open one up and connect wires directly to the button pads. :biggrin:
     
  17. JCTango

    JCTango New Member

  18. Xavier

    Xavier Mid Boss

    THanks JcTango but webpage is the same as the documentation That i already have except they make they make this high speed wooden case ....same video problems tho . Well maybe ill buy an ol school monitor till jrok and others r-up there inventory and I have money . But yes excybers right I want to make this myself . The reason why I mentioned that genesis controllers can have seven buttons is Because somebody was saying in the other supergun post not to use them because they only have four buttons
     
  19. mal

    mal Member

    I've been looking into this myself, and at the moment I'm waiting for Jrok to get back to me about one of his convertors.

    I looked into making something myself and read up on the Analog Devices chips, but one thing has me stumped. The AD725, and I think the others too, want HSYNC and VSYNC, but doesn't a JAMMA board give out CSYNC?

    Is there anyway around this?

    On the other hand the Sony CXA2075M seems to be just right. If only I could find it...
     
  20. IceDigger

    IceDigger Founder Staff Member

    actually I think connecting csync to h-sync will suffice to get a stable picture.. I'm not entirely sure, gotta check my rgb encoder again for the wiring.
     

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