Thought i'd post this here, something I worked out a few months ago and worthy of submission...
This is the PAL NES console board. The silver box is where the voltage comes in (AC) and video and sound is output.
You can desolder the unit from the motherboard:
...and here is the daughterboard:
The guides I found on the net for composite output were for the NTSC console, not PAL, so had to work it out myself.
The parts circled are the parts you need for this mod.
Schematic I made
The diagram above also shows the 7805 (the AC power goes into other circuits, to convert AC to DC, then into the 7805 to make 5V output).