XRGB 2 plus and arcade jamma/pcb problem

Started by acem77, May 13, 2005, 04:20:55 PM

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has any one here found a fix to get the xrgb 2 plus to work with jamma/pcb boards correctly?

there is some problem with the sync signal.
the xrgb thinks the jamma/pcbs are running at 50hz so the screen keeps rolling.
this happens with every board i have tested. my tv will even sync in on most of them by its self. how can the xrgb have a problem?
is there any simple tricks to get the xrgb to think the sync is a diff hz?
most likely it is a full up scan down scan problem.....
like it is miss matching a few +-%


It could also be that the XRGB2+ is choking on the not-quite-100% sync signal most PCBs put out.

When I get my XRGB back from Japan I'll double check, but I once pulled it apart to see how it handled the input for arcade PCBs.  Aside from some resistors along the RGB lines I don't remember what else it did.


it would be great if you find something.
i just want one box for all my needs.


found part of the fix for some jamma boards.
the sync needs to be amped.
i used the same amp that was for the my duo.
the only problem then the rgb values are too high with that.
so i need to make a sync only amp board.

when i was playing ki2 i saw that the volume of the game would effect the sync also. its like the audio circuit needed too much juice so and loud noise or big bass note would make the pic flex a bit out of sync.


Don't you have adjustable RGB levels on your SuperGun ?

And by the way, did you use this kind of amp ?


the rgb pots are on my old rgb to svideo board.
now that is by passed to my xrgb.
and yes that is the same amp it worked awsome for the duo.


QuoteAside from some resistors along the RGB lines I don't remember what else it did.
I checked this when I had an XRGB2 with the idea of making an external circuit for the XRGB2plus. All I found were resistors on that PCB/STD switch, switching it to STD just shorts them out. If I recall they were 220 ohms.

Besides being on the R,G,B lines I think the sync also had a resistor on it; if it did it was the same value as the rest. This would seem to go agains the finding that the sync needed to be amplified. That seems puzzling anyway since arcade boards normally seem to have very strong sync compared to consoles, though as you note it can be a little "non-standard."


Eh, I wasn't very clear. The resistors are in-line on the R, G, B and sync signals inside the XRGB2 when the switch is in PCB, and they're bypassed by shorting when the switch is in STD.

Some value of resistor to ground might also work, or work better or worse, but the XRGB2 has them in-line.