mmmonkey RGB to VGA

I sold my XRGB (I couldn't have been thinking straight at the time!) And I gave up trying to get one at an affordable price again.

The XRGB isn't the only device capable of converter/upscaling to VGA though, more info about available devices are on this excellent site.

Recently I saw this on YouTube which got me interested again. So I've ordered one, via eBay for £25 including postage from china. Search for CGA to VGA and you'll probably see it straight away, it's sometimes listed as GBS 8220. I decided to go for a model with 2 VGA outputs as I had plans for the second output! ( have since tried this on the 1 VGA output model and it works just as well)

I then found this forum post which goes into detail about the equipment and mods needed.

I've read conflicting information about if you do need to split the Sync signal, so I tried wiring it up with and without the Sync Stripper, some consoles which I knew outputted a pure Composite Sync signal worked fine, others which outputted Composite Video worked temporarily. I already have a Sync Stripper designed that I squeezed into a scart plug a while back to try and get my MD working properly. So this can be easily adapted.

With the VGA output, you can easily add scanlines for a more retro screen image.

Rightio, I had to get a Scart socket wired up to this board somehow. It comes with a header to connect to the board which I used to experiment with, before going on and building a Scart socket to VGA connector adapter with audio out socket.

Instead of building all the cables and soldering the connectors myself, I opted to re-use some cables I'd bought. If you want some Scart Sockets and Plugs, then buying Scart Splitter cables can sometimes be a good source.

I buy 3.5mm audio splitters for a similar reason, you can chop the cables up and with a multimeter work out whic is Left/Right/Ground.

Because of my testing, I knew I wanted to build a Sync Stripper to feed the upscaler a pure Composite Sync signal.

I start with a female scart socket, and linked up all the GND pins (not strictly necessary, you can probably use pin 4 for audio ground and/or 18 for video ground, one or the other has been wired up in every game console RGB lead I've seen). Which pins are Ground? Look at this diagram I pinched from Google image search and added some colours.

This RGB to VGA upscaler only handles the image, you can't connect sound to it. For me, I wanted a 3.5mm audio socket to plug in a standard audio cable to my telly. I cut up the splitter cable I had and worked out the colours of the wires and what signal they are (I used a multimeter and a 3.5mm audio plug which I hadn't soldered up).

Soldering this to the scart socket is easy, Right audio - pin 2, GND - pin 4, Left audio - pin 6. IMPORTANT - remember to put the audio cable through the screw part of the scart casing.

And now the video signal. I cut up my VGA cable and again, used a multimeter and another VGA plug to work out which coloured wire was which signal, make a note of these when you do it, or if you're using a VGA plug you can solder onto, you decide the colours! I'm only after a few of the wires/signals - Red, Blue, Green, GND and Horizontal Sync

Signal	VGA Pin	Scart Plug pin	MY Cables Wire Colour	YOUR Cables Wire Colour
Ground	5, 6, 7, 8 or 10	4, 5, 9, 13, 17, 18 and/or 21	Black
Red	1	15	Red
Green	2	11	Green
Blue	3	7	Blue
Composite Video/Sync	13	20	Brown

Before soldering the image wires, test fit the scart socket into the casing, and trim the wires on the VGA cable to the correct length to reach the relevant Scart pins, leave them too long and it's messing fitting it into the casing. IMPORTANT - don't forget to feed the cable through the screw part of the scart plug casing! (I still forget this and have to undo all the soldering to put the screw part back on, not good)

Above you can see that I've soldered the GND, R, G and B wires to the scart socket, and then the next photo shows the Composite video wire going to the Sync Splitter.

You can easily add scanlines to one of the VGA sockets on this board, it's very easy and it's even labelled on top of the board which pin is which VGA signal - this makes wiring in the DIY Scanline Generator very easy. When I added scanlines to the VGA out near the edge of this board, I got some vertical lines on the image, I moved the same scanline board to the other VGA out (the one nearer the middle of the board), it worked fine.

The Upscaler I bought default to Chinese language, to change it I had to press Menu, go to 4 and press menu again, the goto 1 and press menu again.

Some consoles had a wavy image when I first tried them, press and hold the Auto button for around 5 seconds to reset it and hopefully fix the image (it may change your screen resolution also by the way)

It needed a 5v 2amp PSU, with a 2.1mm/5.5mm Power Plug (Maplins part number HH60Q)

Until I find a suitable project box to mount this in, I've attached it to a piece of Acrylic (that was fun trying to cut to size!!)

Update for Sync Cleaner:
I converted one of these boards for someone else, and they had some issues with some consoles, so I decided to move the Sync Cleaner/Stripper from the scart socket to the main board. So when wiring the Scart socket, just wire the Sync signal wire straight to pin 20.

The following photo shows which part of the board carries the sync signal (I've drawn it in red)

I've cut the trace near where it ends, and also scraped away a part of it using a scalpel. To attach the green wire, add some solder to the bit of the board you just scraped away, then add some to the wire you've just striped a bit away from, hold the wire onto the board, heat it up with the soldering iron and both lots of solder will melt together.

The Purple wire is carrying the input to the Sync Cleaner, the Green wire is carring the Sync signal. So that's the Sync Cleaner wired up. I decided to get +5v (red wire) and GND (black wire) from my ScanLine Generator board.

You may or may not want to wire up a switch? It's very easy (but when I tried my consoles, it wasn't necessary).

It seems a lot of people want this setup. Well arcadeforge have developed and now sell the Sync Strike, I've tried one out and it works brilliantly with this VGA scaler. You can even buy the complete setup, Sync Strike, VGA Scaler and SLG3000 as a kit now, a plug and play kit for playing retro consoles on your HD TV via VGA with an awesome picture. Thanks Jochen :-)

If you've tried it with some consoles, and get different results, or you have some consoles I haven't tried, please send me some feedback.

I made one of these for someone else, you can see they're pictures of how it performs for them (it was thanks to this that I realised I need to alter how the Sync Stripper is wired in). The original post on GamesX has also updated with a description of how the ScanLine Generator works:

From ニユ－マン on GamesX
74LS74 changes state with every HSync pulse, so one line is untouched and the next one is blanked (or vice-versa).
The switch selects if the blanking circuit (74LS125) has to erase the even or the odd lines.
When 74LS125 is active the RGB lines are grounded and you see a black line.

RGB to VGA Scaler Modification