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SVGA to RGB SCART

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rikpotts

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Im trying to make a SVGA lead into a RGB SCART lead.

Everything is fine until you have to deal with the sync.
SVGA uses horizontal sync and vertical sync and SCART only uses composite. The are a few bits and bobs to put in the circuit but nothing too difficult.
Here is a diagram
**broken link removed**

I then pulled a female SCART from a DVD player only to find a little board with a few resistors and transistors on and a plug which leads to the motherboard of the DVD player.

The plug running from the motherboard to the scart board has lines I expect to see but no sync lines... or at least that I can tell.

There is...

12v
L
R
GND
V (Composite video out?)
GND
R
G
B
FS
+5v
GND

Here is a pinout of the SVGA
https://en.wikipedia.org/wiki/VGA_connector

and also of the SCART
https://en.wikipedia.org/wiki/SCART

The bit at the bottom of the SCART wiki about Blanking and Switching is relevant.

My question is how does this work when there is no sync going to the SCART board. Surely the few resistors, transistors and thermistors cant sort the sync issue out?

Hope someone can help! It will be so much easier to use this little scart board.
 
You need to tell us what you're trying to do! - I suspect you're trying to use a VGA monitor to watch the output from a DVD player?.

I can tell you now, a lead won't do it - they are totally incompatible - UNLESS you have a suitable multi-sync monitor, which were always VERY rare, and even more so these days.
 
Its a lead to go from the vga on the graphics card to the back of the telly. To get Windows XP MCE on the TV via RGB basically.

My graphics card can output the PAL specification over svga if I force it to.

Ill try and post more info in a bit.. Ive only just found my multimeter!

Thanks for the reply.
Rik
 
Yeah, my graphics card has s-video out. How much of a difference there will be remains to be seen... theres little difference between composite and s-video so....
 
rikpotts said:
Yeah, my graphics card has s-video out. How much of a difference there will be remains to be seen... theres little difference between composite and s-video so....

There's a HUGE difference between composite and S-Video, your problem is the poor quality from your computer - although RGB is far better than S-Video I doubt you will see much difference (assuming you can get it to work) due to the poor quality of the source.
 
So you think its the graphics card thats making windows unreadable and not the tv?
Thats reassuring! If its not the TV which is holding me back then its worth trying to use the svga out instead.
 
I think the mysterious V was the composite sync and the SCART board was setup for sync on blue. I would still need to build a board which combined hsync and vsync into composite sync for it to work.
This board appears to be a switch so that the SCART supports both RGB SCART and composite SCART and also 16:9 and 4:3 outputs.
 
Check another of my websites for details on SCART sockets


But I think feeding a computer to a TV is always going to look absolutely rubbish! - TV's don't have the resolution, and graphics cards don't output a decent signal.
 
rikpotts said:
I think the mysterious V was the composite sync and the SCART board was setup for sync on blue. I would still need to build a board which combined hsync and vsync into composite sync for it to work.
This board appears to be a switch so that the SCART supports both RGB SCART and composite SCART and also 16:9 and 4:3 outputs.
The 4:3 or 16:9 switching is done by providing the right voltage to pin 8 of the Scart socket. It's around 6V for 16:9 and 12V for 4:3. There's actually some tolerance in there but that's the basic concept.

I agree with Nigel, it's the resolution of the TV that will determine just how cack your result is, it won't be anything like readable. Using a TV for a monitor is ok for something like a power point presentation or perhaps viewing some photos (note, viewing not editing) or using it as video out as you are probably trying to do with MCE.

MCE should be workable though, that's the whole point of XP MCE, to use a TV as the display device and with that interface in mind everything is nice and big and bold.

FYI, all the sync information is present in the composite signal so it's possible that your DVD player is deriving HSYNC and VSYNC from that?

David.
 
Last edited:
djtaylor said:
FYI, all the sync information is present in the composite signal so it's possible that your DVD player is deriving HSYNC and VSYNC from that?

That's just made me think! - he's got a composite output, run that as the sync - RGB SCART sockets commonly use the composite video as their sync feed.
 
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