Build Your Own Arcade Controls Forum

Main => Monitor/Video Forum => Topic started by: Brizzle on November 19, 2015, 10:21:53 am

Title: VGA to CGA cable question - No Video
Post by: Brizzle on November 19, 2015, 10:21:53 am

Hi, all!  I searched for this topic but was unsuccessful (though I imagine someone has asked this more than once).
Regardless, I need your help, please. 

I have a 25" arcade monitor, a Makvision 2425 to be exact, that has the 5 video wires, all bare, for connections.  I bought a 6FT VGA Male to 5 BNC Male RGBHV cable, cut the ends off, and connected the wires to the matching colors (See photo for cable).  Here is the link to the cable I purchased : http://www.ebay.com/itm/180910070463?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/180910070463?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

When I hookup a Pandora's Box 3 to the monitor, it displays the game (though with some wavy lines, but that's another topic).  When I connect my computer to the monitor, nothing.  NOW, this is the first time I've worked with CRT Emulator and Groovymame.  This could open an entirely well discussed topic as well.  I will say that I believe I have done everything correctly up to this point.  I have the Radeon 4550 card with Calamity's driver (THANKS, CALAMITY!!!), the red low profile video card in the photo, updated VMMAKER and Arcade OSD, modified ini files in VMMAKER and Mame.

WHile I would LOVE to see someone have a video of the actual point of using Arcade OSD to make the switch from the VGA LCD monitor to the CGA Arcade monitor, my question is FIRST this: 

Is my issue with the cable I am using?  I purchased a different connector pictured below, but I don't have any easy way to connect to the posts on that adapter (here is the link for that adapter : http://www.ebay.com/itm/221480387637?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/221480387637?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)). 

Again, I did make an effort to find this topic, so if it has been answered already, please do comment and help me out.  Otherwise, I'd really appreciate the help, as I plan on helping 2 other friends who want to do the same thing.  I may even make a video that would show the entire process since I haven't found one. 

I want to avoid using the red VGA to CGA convertor that is $30-40 as it only displays at 640x480.  I'm going for the "authentic" emulation experience first.  ArcadeVGA cards would be great, but no one has responded to my posts asking for used ones, and I'm not dropping over $100 shipped on one of those right now. 

THANK YOU ahead of time!!!

Title: Re: VGA to CGA cable question - No Video
Post by: rCadeGaming on November 22, 2015, 09:06:05 am

There are a few reasons I can think of that the PC isn't working on the arcade monitor:

1.  Make sure your cable is hooked up correctly - red to red, green to green, etc.; make sure that H and V sync aren't swapped - do a continuity check with a multimeter against the VGA pinout:

http://www.blogcdn.com/www.engadget.com/media/2006/11/vga_pinout.jpg (http://www.blogcdn.com/www.engadget.com/media/2006/11/vga_pinout.jpg)

2.  Your signal voltage might be too low.  Many arcade monitors require a video signal of 3Vpp or more, whereas VGA outputs around 0.7Vpp, so you might need amplification.  Someone more knowledgeable about this specific monitor will need to chime in.

3.  Sounds like you're new to CRT_Emudriver?  Make sure have it set up correctly and you are indeed putting out a 15kHz signal.  CRT_Emudriver is well documented now.  Start here:

http://geedorah.com/eiusdemmodi/forum/viewforum.php?id=1 (http://geedorah.com/eiusdemmodi/forum/viewforum.php?id=1)

and then go to the GroovyMAME section with any more questions you might have.

Don't bother with VGA to CGA converters that will trash your native resolution.  Don't bother will ArcadeVGA cards, you already have one that's much better.  Yours is an HD 4550 right?

Title: Re: VGA to CGA cable question - No Video
Post by: Brizzle on November 23, 2015, 10:34:39 am

Thanks!  It is a Radeon HD 4550.  I'll be sure to be more thorough in future posts! 

I wired a J-Pac up, and it worked fine.  I didn't do this before because I am going to make this a 4 player arcade.  I was thrown off because not only did my cable not work, my VGA to CGA interface did not work, too.  That said, some games, like Pac-Man, are not running at 15Khz on my monitor... or maybe it's another issue, but that is a different thread.

Thanks, again!
Branden

Title: Re: VGA to CGA cable question - No Video
Post by: mgb on November 28, 2015, 10:08:08 am

not sure if I missed any details but if it worked with a jpac hooked up, I would think possibly your signal voltage was too low.
the jpac has a video amp built in

Title: Re: VGA to CGA cable question - No Video
Post by: kortina on December 09, 2015, 09:23:09 pm

I use one of these:

http://www.ultimarc.com/vidamp.html (http://www.ultimarc.com/vidamp.html)

This allows me to connect my ATI video card (and the CRT EMU drivers) to a R,G,B 15kHz setup.

This also fixes the colours, as it will boost the low (0.7v) signal to 5v required by your display

Title: Re: VGA to CGA cable question - No Video
Post by: Brizzle on December 21, 2015, 03:36:31 pm

kortina, thank you for your message.  Which ATI video card to you have?  I've read that "newer" video cards don't need the signal boost, but when I did get the monitor working for a bit, the colors were bland and dark, not as vibrant as when I saw the 60-in-1 working. 

I ended up getting a Wells Gardner monitor, a newer one, so I'm not sure if I need the cord you mention or a different one.  If I do not need the amp, Ultimarc are sold out :(  Thanks!