Introduction

Some years have passed now since I bought my first ArcadeVGA and a TV set which has never worked for watching TV. This webpage has been online since then. Now, I am revising it and translating it to my native language (thank you guys at Marcianitos.org for encouraging me to do so). I am sorry if the url has changed some times and I did not warn about it. Honestly, I did not imagine that so many people were using this as a reference and help guide, especially among the Spanish community. I must say I never wrote this page with the intention of it becoming popular, but as a summary of several pieces of information I found here and there on the Internet, and also as a way to remember how to build this cable in case I had to repair or remake it some day. Actually, I did not invented anything. This information may be now on many other web pages, with better and clearer explanations. An example can be found here: http://www.idiots.org.uk/vga_rgb_scart/index.html Unfortunately, in those days when I built this cable, there was not much information, pictures, etc. So, it was a kind of adventure. I remember I had some schemes, some quite complex and some quite basic. I decided to go the easy way, and it worked! Happy and excited, I thought it would be a good idea to share and spread this knowledge. I think it can help a lot of people enjoy MAME as it deserves with not much extra cost. You can write to me if you have any question. I do not know if I will be able to help you, because I am not a technician and my knowledge of electronics may be as poor as yours. For this reason, please forgive the mistakes you may find in the following tutorial. English speakears, you can find answers and solutions here: http://arcadecontrols.com/arcade.htm. Spanish speakers, this is the place to go: http://www.marcianitos.org/ -  http://marcianitos.forumcommunity.net/

Why do I need this cable?

Not many people are aware of the fact that the low res arcade monitors used in old arcades and the TV sets we all have at home are basically the same machines. Why then not using a TV for your MAME cabinet? The problem lies in how the video signal from the computer is sent to the TV. No matter the method you use, the picture quality will be pathetic compared to a real arcade monitor...

...unless you are lucky enough to have an European TV. The SCART socket included in our PAL TVs offers a very good picture quality because it receives RGB signals (non-composite) The good news for us is that VGA's output is also, as you know, RGB video signal. This is the reason why the making of this home-made cable is so easy and straightforward. Moreover, using this method, unlike using cards' TV-out to S-video, will not encode and resample the signal through a unique high res interlaced mode, so you have the chance to display native game resolutions. For more info on this subject read: http://www.ultimarc.com/monfaq.html

There is a difficulty, however: VGAs' signal is sent at 31Khz or higher frequencies, too high to be displayed on a TV. So, before we continue, let me clarify then that this project is specially targeted to ArcadeVGA users. Be aware that using other graphic cards with this cable may damage your TV. To tell the truth, I have read reports of this cable working with some conventional cards using custom configuration under AdvanceMAME, but use at your own risk. AdvanceMAME is very hardware-dependent, so I cannot assure that you will get any success with your hardware. You may also find problems of synchronism if you do not manage to configure exact refresh rates. Under Windows, you could also have to use Powerstrip or a similar tool that tweaks your graphic card. I have not tested it though. ArcadeVGA's special configuration output at 15Khz. Using this card, you can instantly enjoy clear picture, vibrant colors, and all this with many custom low resolution non-interlace modes (native and real arcade picture with real scanlines). In other words, it is a very worthy piece of hardware! Recently, some significant progress is being achieved in turning an original ATI card into a ArcadeVGA. It can be a very interesting alternative if you want to save some euros.

I must point out, however, that, although using your SCART TV as an arcade monitor will offer you the same picture quality, you will not have some benefits such as having control over the screen size or position. In some cases you will have to access the service mode of your TV with an internal switch, but it is much more usual nowadays just to enter a code in your remote controller that will grant access to the OSD menu (on screen display), for making the necessary adjustments. Normally, you will notice that the picture does not fit the screen (it is larger!), which does not happen in arcade monitors. This has to do with how TV sets are made. Screen position may vary a little from one unit to another, and customers will not notice this, but they will definitely notice that the screen is not centered if there is a wider margin. This is what technicians call overscan. With the service menu you can easily fix this issue. Consult the instructions or browse the web for information on your model. I took many days for me to find out the code of my 29' Philips: 0 6 2 5 9 6 i+ By the way, before you make any adjustment, write down all the standard values. You do not want to mess everything and not being able to restore it. Once you have made any adjustments (generally under a section called 'geometry'), you will not have to tweak it again. I do, however, when I wish to play movies at 720x480 interlaced, because that resolution mode (the best for video playback) needs to be vertically stretched for keeping the right aspect ratio.

On the other hand, using a TV has many advantages. TVs are cheaper and are available everywhere, especially nowadays, since big and heavy 4:3 TV sets are being thrown away an substituted with 16:9 flat screens for home cinema. Getting an arcade monitor is not so easy and if you find any at a reasonable price, it may be a used unit, which can have some issues with colors or focus. Furthermore, you will probably need a j-pac and an amplifier for it to be used with your computer. However, if you live outside Europe, maybe getting a SCART TV is not so easy nor so cheap.

The making of

To begin with, buy a VGA cable (better a long, thick and shielded cable) and a SCART connector. You will also need a soldering iron and a multimeter (device to measure voltages, resistance, and currents). Save and print the picture above. I have tried to design the schemes as clear and easy as possible, for both soldering and testing. I have also included the standard numbering of the SCART connector (in parenthesis). Take one of the ends of the VGA cable and open it up by removing the screws. Desolder or cut every little cable from the connector. Now, open up the SCART connector and introduce the end of the VGA cable. These little cables should be long enough to reach the U pins, but not too much or they will not fit inside the scart connector. Now, identify every cable you have cut using the multimeter, touching in every little cable in the pins of the VGA connector at the other end of the cable (the needle will move). Label the cables or write down your results. Time to solder. Join the VGA cables as indicated (solder side). 6 cables are necessary at least (red, green, blue, hsync, vsync, and one ground. However, you may wish to solder red, green and blue grounds (to a common ground pin or to each corresponding pin in the SCART connector) in order to avoid any noise and interference. I got this advice from my friend Fernando, who kindly helped me with these soldering issues when I still was not as skilful with this as I am today. It is also a good idea to isolate cables 5 and 10 (VGA) and to solder the VGA shield (the metallic layer covering the cable) to the SCART external shell (ground). Optionally you can solder a cable to pin 17 (8) in the SCART connector and take the other end to one free power lead from inside the computer (yellow plug), which provides 12v. This will allow your TV to autoswitch to ext/aux when the SCART socket receives input from the graphic card, so you do not have to switch using your remote controller, like when you use your DVD player and press the play button. To make it cleaner and shorter, you can use one of the free cables that remain unplugged in the SCART connector and, in the VGA connector, desolder and join it to the cable that brings those 12v. Finally, close the finished connector. Now you can plug it into your ArcadeVGA and into your TV. You have finished. Turn on your computer and enjoy your new 15Khz arcade monitor.

Results

Still not convinced whether this is worth the effort or not? It really depends on how much you appreciate the beauty of the real thing. Well, if you have bought an ArcadeVGA, you may know what I am talking about. If you are happy with how MAME looks on your PC monitor, you may not have seen it before on an arcade monitor or TV set. But, if you remember the games different from what they look now in your monitor, consider it is not only a matter of how young and impressionable you were, because the games actually looked better! The only way to bring their back in their original splendour is to use authentic hardware. Lately, great improvements have been made in simulating the old display of arcade monitors with the help of all kind of software effects. Anyway, just take a look at these screenshots. Notice the differences in contrast, sharpness, blending of colours, pattern... For more examples click on these links:
http://www.oscarcontrols.com/arcadevga/index.shtml
http://www.eibmoz.dk/mamecabinet/index.php (videos),

 

Click for full-sized view

On the left: original picture as seen on a PC monitor (zoomed) On the center: same as before but adding filtering and custom RGB effects at very high resolution mode, trying to simulate the arcade display. On the right: what I see using the ArcadeVGA on my 29" Philips CRT flat-screen TV (ddraw, no stretch, no effects, real low resolution: 392x240).
Desktop (368x240 non-interlaced)		Desktop (720x480 interlaced)
Animated gif (for comparing both displays)		MSDOS games emulated under Windows XP and displayed at native low resolution.