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NFG Forums => RGB + Video Discussions => Topic started by: merchant on February 03, 2008, 11:23:21 PM

Title: Help with weird Arcade RGB>>SCART Issue.....
Post by: merchant on February 03, 2008, 11:23:21 PM
As the title says i have an issue with my setup....

I'm trying to wirer my arcades RGB to a TV SCART socket. The TV works fine, can play various things on it through the SCART connections.

Here's where i am at.

These are what i have the arcades lines wired to on the scart socket.

Video Blue >> Pin 7
Video Green >> Pin 11
Video Red >> Pin 15
Video Synch >> Pin 20 (comp vid/synch in)
Video Ground >> Pin 17

AFAIK, this is how it should be hooked up. Well here is what happens. I get a pictured displayed on the screen that is a very dark grey/black colour. I can see the game running, the synch is fine, no rolling at all. The pictures on the screen have this white outline around them. So basically its a dark coloured screen with some whiteish outlined pics on the screen. However there is one really weird thing. When i go into the TV setup menu using the remote control (picture setup/sound setup etc etc) It shows up in a little box in the middle of the screen, usually the background colour of the menu is a greenish colour. When i open this menu while the game is running, i can see the game being displayed correctly in full colour behind the box!!! It is a little out on the colours because the background of the menu is transparent, so it sort of effects the colouring a bit, but otherwise it's perfectly displaying. The rest of the screen is still the dark blackish colour, and when i close the menu the whole screen is blackish again.....

I have no clue as to what is causing this....why is the video showing properly when the menu is overlayed in front of the picture? Any help is GREATLY appreciated :)

Title: Re: Help with weird Arcade RGB>>SCART Issue.....
Post by: NFG on February 03, 2008, 11:26:12 PM
Basically your TV is set to composite video or Svideo mode, and is reading the Sync line (which typically includes some brightness detail, hence the B/W image you're seeing). 

You'll need to add 12V to the blanking line (via resistor as per the SCART spec) to tell the TV to switch to RGB mode.
Title: Re: Help with weird Arcade RGB>>SCART Issue.....
Post by: merchant on February 04, 2008, 12:34:21 AM
Thanks for the info Lawrence, i've been reading and reading trying to find out what it might be :)

So would it be ok to just connect 12v from my arcade power supply to this line. A constant 12v power feed?

Thanks again for the info.