Scart-to-Scart RGB Mod Tutorial

[huwwatkins]

~Ah - fair enough. I'm guessing I don't need to worry about TP4 then. Did a quick test last night and everything seems to be working. Just need to re-assemble and do a final test.

Update: Everything back together and working! A big thank you to the OP for doing this. Currently playing Wipeout in RGB Looks fantastic compared to the mush that was the RF lead.

[huwwatkins]

Bit of an update: I seem to have a fair bit of background hum on the audio. Any idea what that is likely to be?

Thanks

[zyrobs]

The shielding is not good enough on your Scart cable.

[huwwatkins]

Is TP4 this 'pure sync' that NTSC consoles use?

[zyrobs]

TP4 is c-sync on all Saturns, it is simply not connected to the AV out on PAL machines.

[huwwatkins]

So in theory you could use this instead of TP8 (composite video) as sync? I read on another post here that in some cases it will provide a cleaner image.

[zyrobs]

Yes, of course you can. I did it on one of my old Saturns (desoldered the AV out and hooked up a direct SCART output). Tried both c-sync and composite, and c-sync got slightly clearer image on my plasma TV - but this was because I used a not-so-good Scart cable.

Interestingly, only the recent Digital TVs are sensitive so much to the signal. On my old CRT I can get perfect, artifact free image even on the unshielded crap play-asia cables.

[huwwatkins]

I noticed this too - I think CRT's were very good at masking flaws in the signals fed to them. Plasmas do it a little but LCD's pretty much show every little flaw.

When I get a bigger place I plan on getting a decent second hand CRT so I can hook up the older consoles to it and use light guns!

[zyrobs]

I don't think it's the display type that makes the difference, but the cheap analog-to-digital converters / upscalers in modern TV sets. They are just not designed for that kind of signal input.
On the CRT I use for testing I can spot the difference between 240p and 480i, and there are ZERO artifacts anywhere, even with the cheapest cables. The flaws are not "masked", they are just not there. Yet on my plasma I need the thickest most hardcore cable for good quality RGB picture.

[huwwatkins]

OK So I wasn't happy with my first attempt with this - looked a bit messy as you can see:


So I've re-done it with a new scart socket. Couple of changes I'm going to make. I've grounded the RGB pins and im going to use TP4 for sync and pin one from the AV connect for the fast switching - this will stop it auto switching to 16:9 which it currently does. Also used heatshrink on all the pins except ground to avoid shorting/neatness.

So far:


I plan on doing the vga mod to my newly aquired reamcast soon so this is good practise. Also - I need a new soldering Iron - my sky tronic one is rubbish - any recommendations?

[huwwatkins]

Im trying to take the AV connector off the board so I can connect the wires up there - I am having a bit of difficulty doing this. Does anyone have any tips? Thanks

[zyrobs]

Either use soldering grease + desoldering wire, or a desoldering pump, both can suck up the solder from the AV connector. Should be plenty of guides on google for this.

[huwwatkins]

OK - so I tried using TP4 for sync instead of TP8 and I get left to right wobbling - any idea why?

Edit: put a resistor on TP4 and it now works - annoying the solder 'pad' on TP4 seem to be coming away from the board.

[huwwatkins]

Ok - so it turns out the resistor didnt fix it.

This is whats happening:

[zyrobs]

Your TV does not like the signal. Use normal composite instead.