I am building a jamma supergun with a RGB - VGA converter (model GBS-8220.) It works great with most of my games, but there are a few that don't seem to sync properly.
The games that work: Killer Instinct 2, Crime Fighters, Pit Fighter, Primal Rage, Altered Beast, Silkworm, Captain America, Trojan, Bad Dudes, P.O.W.
Games that don't work: Street Fighter, Mortal Kombat 2, Renegade
Is it possible I need to amplify the sync signal to work with this converter? Thanks in advance for any advice.
Arcade RGB - VGA sync issue
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rikitheshadow
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Re: Arcade RGB - VGA sync issue
I have a few games my GBS-8220 doesn't like at all and some that will work but with badly washed out colors. Mostly caused by medium resolution games......i got a few Sega boards in my collection.
But otherwise I've really only tried it with a few JAMMA games with a Standard CGA resolution. They worked fine as long as the game functioned fine lol.......got a Double Dragon board with scrambled video.
But otherwise I've really only tried it with a few JAMMA games with a Standard CGA resolution. They worked fine as long as the game functioned fine lol.......got a Double Dragon board with scrambled video.
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low_budget
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Re: Arcade RGB - VGA sync issue
All the games I listed DO work. For some odd reason Street Fighter (1) and Mortal Kombat worked with the older model RGB-VGA converter (with dip switches,) but not the newer version (with on screen display.)
I did tie the composite sync and vertical sync wires together (on the GBS-8220). This made Renegade playable, but the screen was bouncing all over. The games that worked before still worked when wired this way.
I also tried a LM1881N based sync stripper to give the GBS-8220 separate vertical sync signal, but had similar results. I later found out this chip is really only for composite video input, not composite sync input.
I had to turn the GBS-8220 brightness and contrast controls maxed out to get a decently bright picture. I may try an amplifier for the RGB signals, as well as the sync signal. I was considering using the THS7314 for RGB, but I'm not sure what to use for a sync amplifier (or if that would even help.)
I'm trying to make my supergun system universal, so I really want to get every JAMMA game to play correctly.
It seems like a lot of Double Dragon boards have display problems. I have 2, one has totally garbled sprites and backgrounds, the other is playable but everything is washed out blue. If somebody knows how to fix these, they could make $$$.
I did tie the composite sync and vertical sync wires together (on the GBS-8220). This made Renegade playable, but the screen was bouncing all over. The games that worked before still worked when wired this way.
I also tried a LM1881N based sync stripper to give the GBS-8220 separate vertical sync signal, but had similar results. I later found out this chip is really only for composite video input, not composite sync input.
I had to turn the GBS-8220 brightness and contrast controls maxed out to get a decently bright picture. I may try an amplifier for the RGB signals, as well as the sync signal. I was considering using the THS7314 for RGB, but I'm not sure what to use for a sync amplifier (or if that would even help.)
I'm trying to make my supergun system universal, so I really want to get every JAMMA game to play correctly.
It seems like a lot of Double Dragon boards have display problems. I have 2, one has totally garbled sprites and backgrounds, the other is playable but everything is washed out blue. If somebody knows how to fix these, they could make $$$.
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rikitheshadow
- Posts:315
- Joined:Fri May 09, 2008 12:15 am
Re: Arcade RGB - VGA sync issue
I got a Double Dragon with garbage, just all the time garbage. I ran my eyes over the board top to bottom and cleaned it, but still nothing but garbage and flipped screens. Even tried it in my JAMMA cabinet and it was still just as bad. I can't say right now I know enough about the integrated circuits to take a probe and diagnose the issue, but it's also just a pain to find a decent schematic for these things.
Experience and Expertise is what I'm working on to achieve at the moment. I want to have a diverse background knowledge of a lot of the electronics used in coin operated amusements sometime in the future.
Experience and Expertise is what I'm working on to achieve at the moment. I want to have a diverse background knowledge of a lot of the electronics used in coin operated amusements sometime in the future.
Re: Arcade RGB - VGA sync issue
I just purchased one of the boards and am having several issues...
Street Fighter 2 CE - image changes randomly (resolution, garbled screen)
Mortal Kombat 1 and 2 - frozen image. Changing the resolution on the converter board refreshes the screen but it's frozen again
TMNT - no issues so far...
Double Dragon - very messed up screen during gameplay. May be DD pcb problem.
anyone have suggestions about a better CGA->VGA converter? I have an excellent CRT monitor I want to use for my project.
please help!
Street Fighter 2 CE - image changes randomly (resolution, garbled screen)
Mortal Kombat 1 and 2 - frozen image. Changing the resolution on the converter board refreshes the screen but it's frozen again
TMNT - no issues so far...
Double Dragon - very messed up screen during gameplay. May be DD pcb problem.
anyone have suggestions about a better CGA->VGA converter? I have an excellent CRT monitor I want to use for my project.
please help!
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rikitheshadow
- Posts:315
- Joined:Fri May 09, 2008 12:15 am
Re: Arcade RGB - VGA sync issue
Right now I can say there are some more converters out there, but they are no where near cheap.....
http://www.converters.tv/products/vga_to_vga/425.html" onclick="window.open(this.href);return false; That one at least allows you to convert it over 3 different ways in any combination....but I dunno how well it works
Another suggestion to some is that some games have an odd sync issue or sync output for that matter. Could either be positive or negative in that manner.
There is a custom designed application board that is used to clean up these signals very easily....I suggest searching JROKs RGB Sync Cleaner
I just really can't say we should of expected much from this $40 scan converter.......it works great with most JAMMAs but not all. The one's specifically designed into certain monitor applications work a lot better. For example Digital Tri-Sync monitors have a specialized way of converting the signal over to a digital signal that can handled easier by the monitor's display. But there in lies the problem, we can't work with a digital signal really, especially for a super gun of sorts.
http://www.converters.tv/products/vga_to_vga/425.html" onclick="window.open(this.href);return false; That one at least allows you to convert it over 3 different ways in any combination....but I dunno how well it works
Another suggestion to some is that some games have an odd sync issue or sync output for that matter. Could either be positive or negative in that manner.
There is a custom designed application board that is used to clean up these signals very easily....I suggest searching JROKs RGB Sync Cleaner
I just really can't say we should of expected much from this $40 scan converter.......it works great with most JAMMAs but not all. The one's specifically designed into certain monitor applications work a lot better. For example Digital Tri-Sync monitors have a specialized way of converting the signal over to a digital signal that can handled easier by the monitor's display. But there in lies the problem, we can't work with a digital signal really, especially for a super gun of sorts.