nfg.forums

Hi there!

I recently bought a Dreamcast and got not one but two RGB SCART cables, both with connectors that could easily be opened. Since I had no use for the other cable, I asked a friend of mine (I've never even touched a soldering iron, heh) to make a DC VGA adapter out of it for me. We even had a working cable at one point, but the image quality was really bad due to a lengthy and badly shielded cable. However, after the cable was cut and the DC end re-soldered, this happened:

 http://koti.phnet.fi/~vv/vga_vaerit.jpg

Sometimes fiddling the cable around gives a picture which is almost ok, with only a few flickering stripes with those totally screwed up colours:

 http://koti.phnet.fi/~vv/vga_raitoja.jpg
 http://koti.phnet.fi/~vv/vga_raitoja_2.jpg

My guess is that he botched one of the "mode select" pins on the connector somehow while re-soldering. What exactly does the DC output on the RGB pins when the "RGB select" pin isn't connected to GND? YPbPr component video? Or is it just random garbage? If so, why is there a "RGB select" pin at all, since there are separate pins for S-Video & Composite anyway?

http://www.gamesx.com/wiki/doku.php?id=av:dreamcastav says "ground either one for two kinds of 15kHz RGB, ground both for VGA", but it seems like grounding one is enough for the DC to output VGA frequencies. And what's coming out without the other pin grounded (assuming that is the problem) certainly doesn't seem like any kind of RGB. :P

He did try fixing the DC side connector, but the cable simply doesn't want to work reliably anymore, no matter what he does.

Do you think the problem is the RGB select pin (in which case I guess the DC side connector has been rendered permanently useless for any RGB purposes, SCART or VGA) or something entirely else? Also, what exactly is the screwy-colours-crap the DC outputs when the RGB select pin isn't connected to ground, assuming that is the problem here? Is it something which could be useful (meaning the connector and cable wasn't wasted after all :-) or merely random garbage?

It is a PAL DC if that's of any significance. That's why I wanted a VGA cable in the first place -- Ikaruga, for example, runs in 50Hz mode only (with music badly out of sync) on PAL consoles no matter what kind of a bootdisc you throw at it. :-( But VGA mode is always 60Hz, and my PC monitor doesn't mind being turned on its side at all.

Which two DC RGB Scart cables did you pick up?  Could you post pictures?

QuoteSometimes fiddling the cable around gives a picture which is almost ok,

Ground both select pins + make sure other wires aren't touching.
Ensure that ground from the DC always goes to the monitor.

QuoteWhich two DC RGB Scart cables did you pick up? Could you post pictures?

I have no idea where the previous owner bought their cables, but both are RGB euro-SCART cables. The other one (which we didn't destroy yet) has 2 RCA plugs coming out the SCART connector for audio.

Here are some pics of it:

http://koti.phnet.fi/~vv/dc_scartcable_1.jpg
http://koti.phnet.fi/~vv/dc_scartcable_2.jpg
http://koti.phnet.fi/~vv/dc_scartcable_3.jpg
http://koti.phnet.fi/~vv/dc_scartcable_4.jpg

Like I said, the other cable was identical except that it didn't have those RCA plugs. Oh and the tape wasn't there originally, the halves were glued together. After I opened the connector the glue didn't want to hold anymore, so...

I also bought a third RGB cable (with RCA jacks for audio) separately before the console arrived because I thought the previous owner would just throw in a crappy RF modulator, but it has a connector which is similar to my official Sega RF modulator. :-( It has only those pins which are required and can't be easily opened, at least without a saw or something. I also have a 3rd party RF modulator which came with this console and has all the pins on the connector, but likewise can't be opened without much effort.