RGBS off the ribbon connector?

Ubergeek

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This may be a silly question, but:

I noticed on the Jamma cable pinout that video is split into RGBS coming off of the connector. If I want to send this to a test monitor can I either

a) send it to a monitor with composite in and put BNC connectors on each lead (I know they are thin... don't know if they would even hold up)

b) RGBS to composite and use an RCA connector to a standard TV

c) Have someone here tell me the best way to wire a test monitor (and what type to use) from a Jamma harness.

I am a video engineer so I know just enough to be dangerous when it comes to A/V, but I am not familiar with arcade monitor signals and how they are sent, if they are a 60Hz signal, or what. ANY education is appreciated.
 
Signals from a Jamma game board are seperate Red, Green and Blue, with negative composite sync. Refresh rate is 15.75khz (NTSC rate). Signal levels are around 4v, sync is TTL.

For a test monitor, you can use many different types of monitors. The simplest and obvious would be just a spare arcade monitor. Old computers in the 80's (Apple IIgs, Commodore Amiga, Atari ST) used the same type of video signal, so a lot of people, myself included, simply use an old computer monitor. IBM type CGA monitors can also be used, if you modify them to take analog video as opposed to digital.

You can also purchase a signal converter to convert the RGB signal from the game board to composite video, and feed it into a television.

For old games that use monochrome monitors, the video signal is just plain composite video - you can use a TV set or a composite computer monitor.

For vector games, you can use an oscilloscope (you'll see retrace with no Z input to the 'scope, but it's good enough for testing)

-Ian
 
What do you use on the end of the leads? BNC?

Whatever you want to. There is no real set standard. I personally use DB-9 connectors for my test rig, in the about the same pinout as IBM CGA.

Arcade monitors traditionally use a .156 spacing molex header, four pins together for R, G, B and Ground, and two off seperate for H and V negative sync. But some newer monitors put these together, some have .100 spacing pins, some have different connectors, etc. I just used the DB-9 on my test rig for convenience. Then, whatever monitor I want to connect to it just needs a simple DB-9 to *whatever* cable. The test monitor I use is an old Apple monitor, which has it's own pinout on a 15 pin dsub connector - so I made a cable for that to connect to the test rig. Any time I want to hook an arcade monitor up, I just swap the cable.

-Ian
 
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