Posted by Brian Lewis on November 15, 1999 at 14:41:27:
In Reply to: VGA output, voltages, and arcade monitors (Brian Lewis, Andy Geezer, et al) posted by Joe on November 15, 1999 at 11:32:16:
FWIW -
When I used to build any (x)->JAMMA stuff, I
almost always put 3 10uf caps on the RGB lines.
Just to remove the DC offset that consoles/PCs tend to chuck out in
their video.
Then, I decided to not bother,
partly out of laziness but I also couldn't see how the
small/constant offset was going to cause any real damage.
It does mean the ptp output is generally smaller on consoles/PCs
then arcade boards, but you can compensate for that with
a quick adjustment of the monitor.
I've been running consoles/PCs through arcade monitors
for a couple of years (might even be 3 years for the Saturn stuff)
- with no problems whatsoever.
So...
if you want to be on the safe side, put caps on your RGB lines.
but - like I said - I've yet to see any problems.
Brian
-----
: To the video gurus of the group:
: In a previous thread, I mentioned troubleshooting monitor problems with a friend who owns/operates 500+ arcade games for a living.
: We tested my video input for voltages, just to make sure the monitor was getting the signal it needed.
: He said that JAMMA games, on average, send an R, G, or B signal around .5 volts. This will vary slightly depending on the picture being sent to the montior (i.e. a football field requires a lot of green).
: When we tested the output voltage from my video card (ATI), the voltage was higher. Red, I believe, was nearly twice as high.
: His concern was the excessive wear and tear on some of the electrical components. This higher voltage can be rough on the resistors, etc. Can you say "premature Cap Kit"?
: I would love to hear your thoughts on this subject. Can/should these voltages be controlled?
: Just looking to make ArcadeOS better and BYOAC safe,
: Joe