mmmonkey Master System 1 and Megadrive 1 Scart Lead

This RGB Scart lead is a very easy one to make and is essential if you want a decent colour picture from your 50/60Hz Megadrive. It only has Mono sound, which is all the official leads had, and the Master System only supports mono sound anyway. If you want one that outputs Stereo sound for your Megadrive 1 then follow our other guide. (You don't necessarily have to build the whole thing, you could start with an RGB cable for another console and just alter it)

Please note, there are two different 8 pin din connectors! The MD1 and SMS use the "U" type

You'll need an 8 pin din plug, a Scart plug, some suitable cable with at least 7 wires and a few resistors - 3 x 75 ohm and 1 100ohm. You'll also need some very short pieces of thin wire, you can just trim a short length from your intended cable, and pull the wire from that if you haven't got any scraps of wire.

These diagrams show the pin numbering of both the 8 pin din and Scart plugs, both are as viewed from inside the plugs, i.e. the side you solder the wires onto.

Signal	8 Pin Din pin	Resistor	Scart Plug pin	Wire Colour
Ground	2	None	4, 17 and 21	Black
Composite Video	3	None	20	Yellow
Red	6	75 ohm	15	Red
Green	5	75 ohm	11	Green
Blue	8	75 ohm	7	Blue
AV Switch	4	-	8	Brown
RGB Switch	-	100 ohm	From 8 to 16	-
Audio	1	None	2 and 6	White
Not used	7	-	-	-

Start by stripping the cable, on the Scart plug end strip back the outer cable by about 1.5 inches, then strip back each inner wire by just a few millimetres. On the 8 pin din end strip back the outer cable by an inch, then each inner wire by a few millimetres. Tin all of the exposed wires ready for soldering. Ignore the orange wire in the picture, it's not needed.

Now prepare the 3 75 ohm Resistors, trim the legs so they are only a couple of millimetres long, then tin them, if you've got some heat shrink tubing the right size to go round an resistor tightly, then cut 3 pieces so that it is a little bit longer than each Resistor (this photo shows the 100 ohm resistor as well, ignore this - do not trim it short).

For the 100 ohm resistor, bend it so that it reaches from Scart pin 8 to 16, if you can - insulate the resistor to prevent any possibility of a short circuit.

Prepare the Scart plug, melt some solder into each of the contacts that we need to solder a wire or resistor onto (that's pins 2, 6, 7, 8, 11, 15, 16, 17, 20, 21) for pin 21 (ground) we have to solder a wire to the outer surround of the Scart plug, the easiest position is as shown below.

Before we solder the wires into place, start with the resistors, solder the three 75 ohm resistors to the necessary pins (7, 11 and 15). It doesn't matter which way the resistors goes in.

Now we can solder a wire from pin 2 to pin 6 (these are left and right audio), followed by some ground wires, first from pin 4 to pin 17, then from pin 17 to pin 21 (the outer shielding).

The first 2 photo's below show the incorrect way of fitting the 100 ohm resistor, please solder it from pin 8 to pin 16 as shown in the third photo.

To finish the Scart plug, simply solder the wires to the necessary pins and resistors. Use the table above to make sure you're soldering the wires to in the correct places, for ground just solder the wire to pin 4 as we've already linked the other's up. Don't worry if your wires are a different colour, just substitute mmmonkey's colour for your colours, just make sure you've got them written down/printed out as it makes soldering the other plug much easier. If you've got some heat shrink to cover the resistors, then place it on the RGB wires before you solder them, then heat the tubing to insulate all of the wire/resistor joins.

Then assemble the Scart plug, as you've finished with it. The photo above is slightly incorrect, it shows a brown wire going to a resistor which then goes to pin 16, this should have gone to pin 8, which should now be linked by a 100 ohm resistor.