Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: BLACK KNIGHT on December 23, 2003, 08:23:45 pm
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Just curious as to why this won't work and would would happen if you tried. If I know which pins on the monitor connector are R,G,B,sync, etc. Then I connected the individual wires from the game to those pins...what would I get??
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Garbage, unless you have one of those PC VGA monitors that accepts a 15KHz signal. My Princeton Graphics 1400 is one of those.
Since you're outputting a 15KHz signal to a monitor that is looking for a signal usually somewhere 30KHz to 55KHz, at best you'll have garbage. At worst you'll blow your monitor.
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Hahahaha, would it really blow the monitor?!? I would've thot that 15khz is less than 30 to 55khz and nothing much would happen except garbage. Glad I asked if that's the case tho!
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A late 90s monitor or newer will probably be unharmed (but also has basically zero chance of being able to accept the signal). Most will just blank the screen, or display an out of range message.
Many mid 90s monitors are dangerous to try this on, because few can display the signal, but many of them can possibly be hurt by it.
Many early 90s monitors will display the picture and very nicely, but will wrap around the left 3" to the other side of the display (showing it superimposed over the right side), and this will not adjust out, no matter how hard you try (not even if crack open the monitor and futz with it).
I have so far tested 2 early 90s 14" models with Vantage giving arcade output, and both of them did that. I went ahead and tested one of them with a Time Pilot board, and it did the same thing as it did when Vantage was set to arcade output.
Those monitors do make decent test bench monitors though, good enough to see that your boardset works, and to run through test mode on.
A scant few will display the image PERFECTLY.
The best way to test for this is to just get a comp, install Vantage, and Space Invaders and set the shortcut to run it in arcade mode (I use Vantage for this because it is small, simple to get arcade output, even on top of Windows, and is fast enough to run on anything).
Then you just hook up your "possibly arcade friendly" early 90s monitor to it, and hit your shortcut. If it doesn't come up, then hit escape really fast.
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All JAMMA games generate R-G-B color and composite NEGATIVE sync. Computer monitors accept POSITIVE sync. Early 80's computer monitors were CGA (standard resolution) but again, they were positive sync units. However, if you have a Medalist Marketing DARTSTAR electronic dart machine (the ones used in taverns), they have positive sync output connector on the game board for use with a CGA computer monitor. Dartstars are popular here in the Pacific Northwest.
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You would need a scan converter to convert the 15Khz signal to a 31-55Khz signal
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Okay, so it does sound like this would be a bad thing to try with a decent monitor. Just checking.
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Okay, so it does sound like this would be a bad thing to try with a decent monitor. Just checking.
There is no chance a DECENT monitor can do it. The VGA monitors that can do it are almost all 1990ish vintage ones with 14" tubes.