regulate nonstandard sync signals on arcade pcbs?

[acem77]

i have a few pcbs that will not work with my xrgb2 plus because of irregular sync signals. the same games will not work an some sony tvs.(like my 36 wega:P)
to name a few nba jam, ki 1+2, mortal kombat1+2+3.
is there a device that can regulate the sync to an exactable level?


if not my hope is the xrgb3 will work!
plan to upgrade from my xrgb2 plus to that.

[viletim!]

There are two things to consider...

There's the vertical sync frequency - some TVs won't sync to a signal if it's not at TV frequency (50 or 60 hz with a tolerance of about 1 hz). So games (like Mortal Kombat i think) that run in between those two might not acheive vertical sync.

The problem is what i'll call sync timing -  the actual length of each pulse. Maybe a horizontal sync pulse is too long or a vertical pulse too short or something like that. Though TV sync circuits are pretty versitile and usualy don't mind this sort of thing. It really causes problems with the AD72x video encoders though .

The former is extremely difficult to fix at the source - you basicaly need a scan converter - the equivilant of another XRGB. Maybe it's easier to replace/modify the TV. The latter is relitively easy and can be done with a few 74ls chips.  

[Endymion]

I'm sure Lawrence will correct me on this but isn't this why the XRGB (1) is better overall for arcade games? I recall reading it has support for more modes or some such.

[acem77]

well then i really hope the xrgb3 does the job
i better not hold my breath for some one else to test this ....
not many people will spend that money then also have a super gun to or the same pcbs to try....

i do plan on buying it in the future sice it suports 720p.
i am sure the image will be boosted past 640X480 to 1280X720.

[TechnicalMonkey]

What type of singal does it output? You can probably use a series of scan converters to get a good TV or VGA monitor signal depending.

[Drewman21]

Wasn't Jrok over on the neo-geo.com boards working on sync board to get golden Tee and the Kombats to work with his encoder?  He should be getting close to having them done i would think. I'd check in with him back over there and let us know.

[Segasonicfan]

There is a cheap solution to this problem I have found.  While some capatibility is still dependant on the TV you're using, I've had a lot of success with using a new auto sync splitter called the ISL59885.  It's basically an advanced LM1881 variant that doesn't require a 680kohm resistor to set the sync but auto syncs it internally instead.  It's a magnificent little chip you can get at Intersil's site for ~$6 and worked very well with my Raiden II board which has the same sync problem as the midway games (set at 54khz).

-Segasonicfan

[TechnicalMonkey]

If it is 54kHz maybe the GXP-2000 would be suitable for SD down conversion.

[Guest]

There is a cheap solution to this problem I have found.  While some capatibility is still dependant on the TV you're using, I've had a lot of success with using a new auto sync splitter called the ISL59885.  It's basically an advanced LM1881 variant that doesn't require a 680kohm resistor to set the sync but auto syncs it internally instead.  It's a magnificent little chip you can get at Intersil's site for ~$6 and worked very well with my Raiden II board which has the same sync problem as the midway games (set at 54khz).

-Segasonicfan

if the chip is used it can stay and not mess up the rest of the arcade pcbs sync signals?

do you have a drawing of how you wired up the chip?

what games have you tested  just raiden 2?