DVI video questions

[dboeren]

OK, forgive me for being stupid here...

Does anyone know where I can find some good information on DVI video?

Some things I'm particularly interested in:
1. Is is easy/cheap to convert an NTSC (RCA) signal to DVI?

2. How do I find out if a video card can output DVI?
(I have a GeForce2MX, but would be willing to buy a card if it was not
too expensive)

3. What resolution can DVI support? Is 640x480 OK? Higher?

4. How good is DVI compared to VGA or other common standards?

Thanks!

The reason for all of this is because my new Sega Megalo 410 cabinet has a DVI input for the screen. It occurs to me that this can be put to good use, possibly for a nice MAME hookup without needing to mess with complex video setup or maybe for playing consoles in if it's easy & cheap to convert standard NTSC video to DVI.

ps - rest assured I am *NOT* going to modify the cabinet. Anything else i run in it will go through the JAMMA and DVI interfaces. I do not condone the deJAMMAfication of arcade cabinets to make MAME boxes.

[Dave_K.]

There are a couple versoins of the DVI connector out there...some have analog RGB pins included for backward compatibility with analog monitors. I'd guess your megalo projection monitor is really analog...so good chance your DVI port supports this.

Anyway, most modern video cards output DVI, but if yours doesn't, then you just need a DVI->VGA adapter which just routes the VGA to the analog pins on the DVI converter. Most video cards also ship with this cable and adapter...so should be cheap.

I doubt your megalo will do 31khz though, so hooking a computer to it will require an arcadevga card (or something similar).

Here are the various DVI plugs. You can search google for "dvi pinout" for more info:
http://www.networktechinc.com/dvi.html

[dboeren]

I doubt your megalo will do 31khz though, so hooking a computer to it will require an arcadevga card (or something similar).

Actually, I believe it DOES accept 31khz. I can verify this when I get home and check the manual, but when I was looking inside there were two video hookups, one labelled 15/31 and the other labelled 24.

I'm totally OK with buying an ArcadeVGA if one is needed. I was just thinking that if I can use the DVI input directly I will save some cash AND probably get a better picture out of it. On the downside, it would be a cabinet-specific setup. There's something to be said from having it work in any JAMMA cabinet.

Also, I haven't figured out the sound yet. jpac does the inputs. ArcadeVGA does the video. But there doesn't seem to be a standard way to hook up the sound for some reason...

[Dave_K.]

Well sounds like you are in luck if one of the hookups says 15/31. So all you need is the dvi->vga adapter (it looks like a null modem and just converts the pinsouts from one to the other).

As for sound, you could hack the existing amp in your cab by making your own cable with matching molex connector. Just trace the sound input wires from the jamma plug to the amp.

[japtor]

1. Is is easy/cheap to convert an NTSC (RCA) signal to DVI?

2. How do I find out if a video card can output DVI?
(I have a GeForce2MX, but would be willing to buy a card if it was not
too expensive)

3. What resolution can DVI support? Is 640x480 OK? Higher?

4. How good is DVI compared to VGA or other common standards?

1. no clue about dvi converters, but if the megalo is using dvi-i, a ghetto console vga box (and vga-dvi adapter) would be the cheapest option, up to the high quality expensive vga converters.

2. look at the ports, compare to the link in daves post. most video cards w/dvi use dvi-i. if yours doesnt have it and you want dvi, its a semi standard feature, shouldnt be too hard to find on a moderately cheap card.

3. not sure how low it can go, but at least 640x480 on the low end, and up to 1920x1080 on the high end with single link dvi (although manufacturers have figured out how to pump it to 1920x1200 with some tricks).

4. if its running the analog signal (through dvi-i), then its basically just vga. if its running digital, then the signal stays digital and is all pure and pristine and crap. im guessing it depends on the display though, if there is an analog conversion, itll just keep the signal digital until it gets to that point.

what kind of dvi input does the megalo screen have? if its not dvi-i it might complicate things a bit (at least different simple adapters, at most, expensive adapters depending on the use).

[gersoncampos7]

i think the megalo only had RGB or common monitor ports chan you post a picture of the rear ports on your megalo?

mine has a vga and a port that looks like a centronics 50 or 60 pins on the rear. but are those for input or just for output.

Thanks

i have already sent you a PM on some questions related to megalo 410

[undamned]

RE: DVI

DVI-D is directly compatible w/ some flavors of HDMI, so you can hop on ebay and nab an HDMI to DVI adapter and run your DVI-D source to your HDMI display.

DVI-A is basically VGA w/ a different pinout, so you can hop on ebay and nab a DVI to VGA adapter and run your DVI-A source to your VGA display.

DVI-I has the pins present for both DVI-D & DVI-A so you can run whichever cable is appropriate as long as your DVI source will run both modes.

In regards to converting composite to DVI-X, that would be a worthless thing to do. Your picture quality would be horrific (probably even worse than running composite on a standard NTSC TV).
-ud

[gersoncampos7]

My megalo 410 came wired with standard jamma that means it gets mono audio out.because jamma pin L an pin 10 hold speaker (-) and speaker (+) respectively. on a neogeo pinout Pin L holds left audio and 10 holds Right audio on the jamma fingerboard. capcom systems hold a different pinout and sega system 16 changes that too. i do not know if the fisrt board where jamma wiring harness gets connected that is port cn5 on board 839-0894 (which can hold up to 34 pins only has 28 wires comming out from it) maybe the last 4 pins on board can vild something else from harness. port CN7 on same board that has 50 pins in my cabinet seems to send wires to rear centronix port. and cn10 on same board seems to send video to board 839-0904 where audio is managed and the rest of the pins to the front panel where audio volume knob, test and service buttons, coin signals and the wires that plug to each of the 4 buttons per player plus joysticks of each of the 2 players including ground.

maybe if some one gave us a scan of the service manual we can find that out! or maybe mr megalo can help us

[gersoncampos7]

And yes.. it is true that megalo can handle 15, 24 and 31hz. i did plug video from pc on the vga wire and video shows but my video card does not send the 5 vold signal from video. i did order a jpac and i am waiting for it to arrive. they say it has a video amplifier to rise signal up to 5 volts (arcade standard) i am using a tnt2 riva 16mb agp 4x video card and it outputs video at 15 hz (from one of my other arcades) to an orion 19 inch arcade monitor.

the monitor is in my case a hitachi c41-31S projection monitor, that sadly i have not found out the proper remote to configure and align video properly and i dont find an webpage on hitachi website or anywere else to learn from.


if someone else has info related to megalo 410 please help