RGB SCART to VGA cable/adaptor

[Irongiant]

I need to make up an adaptor to connect an RGB SCART cable to a VGA monitor - is this just a simple matter of connecting up the appropriate wires, or are there any other requirements?

My reasons for doing this are as follows - I need to test some old arcade PCBs that output an RGB signal with a horizontal scan rate of 25 KHz - I've found someone with a VGA monitor that will sync down to 24 KHz which is perfect. The existing setup of my test rig has the RGB (and sync) going to a male SCART connector which plugs into my standard resolution test monitor. On the odd occasion when I need to test a medium res board (at 25 KHz) I would just like to unplug the RGB SCART plug from my standard res monitor and plug it into a female SCART connector, the other end of the cable being connected to a VGA connector (or RGB, horizontal and vertical sync if using the BNC connectors on the monitor).

Thanks

[raisinland]

I'm in the US and therefore new to SCART, however I believe it carries a low voltage composite sync that will have to be amplified and split to generate VGA compatible TTL level H and V Sync.

Ah, found a link:
http://www.epanorama.net/documents/vga2rgb/scart.html

One for Sale:
http://www.amazon.co.uk/Hama-SCART-To-VGA-...e/dp/B0002W69MY

-John

[NFG]

Typically you don't need to split the composite sync signal.  I just tie the csync line to both H + V sync on the VGA monitor and it tends to work just fine.  In fact I've never had it fail to work.

I have heard that it's not always wise to do it, but I've done it to all my monitors without trouble.

[Irongiant]

Thanks guys, I appreciate all the help. From looking around a bit more it looks like the monitor may also support composite sync on green or even composite sync on the horizontal sync input. Fingers crossed. :-)

Am I likely to have any issues with the strength of the RGB and sync signals from the arcade board to the VGA monitor? I mean, if for example they were too weak for the monitor what would be the solution? If too strong then resistors could be added to the cable, but if too strong ..... ?

[ken_cinder]

Thanks guys, I appreciate all the help. From looking around a bit more it looks like the monitor may also support composite sync on green or even composite sync on the horizontal sync input. Fingers crossed. :-)

Am I likely to have any issues with the strength of the RGB and sync signals from the arcade board to the VGA monitor? I mean, if for example they were too weak for the monitor what would be the solution? If too strong then resistors could be added to the cable, but if too strong ..... ?

Whatchoo fink? I think you mean too weak, Capacitors....

[Irongiant]

Ooops, yes - typo.  

[lalin]

Irongiant,

Please, let us know how it went.  I am in the US (no SCART in these valleys ) and I am breaking my head trying to figure out how to connect and RGBS (RGB with Composite Sync) signal to my HDTV (support both VGA and Component) without having to spend much on an expensive ($120+) converter.

Lawrence's suggestion of connecting the sync signal to both v-sync and h-sync sounds tempting, but I haven't finished (not even started actually) my mod yet to try it out.

Thanks All ,
Lalin

[ido8bit]

It may be worth tracking down the service manual for your HDTV.  Some (eg Panasonic from memory) will accept RGB over the component input if a setting in the service menu is changed.  This applies to some sets where there is a Euro model using the same/simliar chassis.  Change the right setting and the component input basically becomes a SCART input without a SCART connector.  

Note, I have not tried this.  I read it when I was researching what TV to buy, but in the end I just tracked down a Euro model with SCART (both Euro models with SCART and Asia/Pacific models with only component are available here).

There are various free manual download sites around, but the best ones are often not in english (though the manuals usually are) so searching them isn't always easy.  

[Irongiant]

Thanks, managed to get it working just by connecting up the relevant pins (and the monitor accepted composite syn on the horizontal sync BNC input).