Mega drive/genesis RGB SCART cable problem.

Hey. Some time ago I bought Mega drive (pal, first model but without this "high definition blah blah blah" inscription). I read somewhere that you get awesome viedo quality when you have an RGB cable so I asked a friend of mine to make one for me. He followed the chart below to make it minus the converter part and something went wrong.


The picture is unstable, horizontal lines move to the sides and the images generally freaks out, what could go wrong?
The link to what the console spits out below.

https://www.youtube.com/watch?v=Z0y46NCXF8I&feature=youtu.be

 

Check your voltages are correct on the switching pins. If you ignored the suggestion that you need something to convert the 5V to 10-12V, then you're telling the TV to expect a 16:9 signal. Shouldn't be the end of the World, but you definitely need 1-3V on pin 16. Use the right resistor if it isn't.

You might want to try without the caps, although you shouldn't have that much of an issue from that.

Does Mega Drive do composite sync, or do you need sync from pin 1?

 

Try using C-Sync instead of Composite Video for sync. It is pure sync so it is very stable. It is located on pin 1 of the Mega Drive A/V Connector. Connect C-Sync to pin 20 of the SCART connector instead of composite video.

Pin 16 is the RGB/Composite select pin and should receive 1-3 volts for RGB video mode and no voltage (don't use this pin in that case) for Composite video mode.

Pin 8 is the aspect ratio select pin. No voltage (pin is not connected) means that you must select it manually with your TV's settings. 4.5-7V means it is a forced 16:9. 9.5-12V means it is a forced 4:3.

You should've had the cable wired for Stereo audio via a separate cable that runs to the headphone jack from the SCART cable.

 

Thanks guys. Pin 16 must be getting the right voltage, because the TV switches to RGB mode automatically when I switch the console on. We also tried soldering the caps out and it had no effect, maybe the image was a little bit less stable. So I guess we'll just use the C-sync instead of composite and I'll tell you what's the outcome.

 

Update guys. Sadly, after soldering din pin 1 instead of 2 to scart pin 20 the result is the same. Is it possible that there's something wrong inside the console itself?

 

make sure you connect ground aswell most modern tvs hate no ground.

 

At first we actually didn't connect the ground so I thought that was the reason the image is bad, but no. After connecting the ground it looks the same, nothing changes. The inside of the console seems to be nice and clean as well.

 

Did you connect ground to 4,5,9,13,17,18, and 21?

 

Is your megadrive a "MEGADRIVE RGB" ?

 

If you use CSYNC from the Mega Drive (and it's a MD1) you need to make sure your TV is not using a 75Ohm termination resistor at the CSYNC line. If it is, it will lower the voltage at the CSYNC input at the CXA chip and will screw the timing for the clamping circuitry inside the CXA chip completely.

On your case, it looks like the voltage for the CSYNC signal is wrong. The RGB signals seem to be fine. You might want to mod the MD to use CSYNC out pin from CXA (it's disconnected to save parts. SEGA silly mistake)