need know arcade monitor interface?

[initial_y]

is arcade monitor composite sync input or H sync + V sync

how to convert composite sync to H+V?

[MonitorGuru]

Neither.

Arcade monitors are RGB not composite video.
They require 0-4 or 0-5 volt RGB signal range.
Sync is generally negative based and separate pins for horizontal and vertical.

That said, there are some arcade monitors that accept posive based sync, and most arcade monitors support combined horizontal+vertical sync, but on a separate wire (e.g. not combined with a signal such as Green)

[initial_y]

On JAMMA connector there is a "video composite sync" pin. Is this combined H+V sync?

[MonitorGuru]

Yes, but it's generally referred to as "Composite Sync" as the words "Video Composite" could mean a composite video signal (luminance+brightness) like the yellow RCA plug out of the back of a VCR.

Composite Sync is generally negative based and most arcade monitors accept this combined signal on the H sync connector and split it internally into H/V so you won't have to convert it yourself.  Typical worst case, you can just run a jumper from the H sync connector to the VSync and basically run the sync into both like a Y adaptor, if the monitor doesn't do it automatically.

Only a few monitors would require you to actually electrically strip the signals from each other and feed them separately.