It has been tested with an Atari STFM. The chip (IC1) is a 74LS86. All resistors are 250mW 5%. C1 is a 100nF capacitor, the type and voltage rating are not critical, but I suggest a ceramic type. I used the P9 power connector on the GBS-8200 V4.0 board to "steal" a +5V supply for this circuit. Red is +5V, black is 0V/GND. Connect the Atari STF(M)/STE up as per the table below. On the schematic diagram, the output is called "Comp Sync out" but in the table I refer to the same signal as CSync. Code: Tout sélectionner Atari signal wire colour GBS-8200 V4.0 board 13 pin DIN P11 connector 6 ------green video---green wire------------"G" 7 ------red video-----red wire--------------"R" 9 ------HSync---------to 78LS86 circuit 10 ------blue video----blue wire-------------"B" 12 ------VSync---------to 78LS86 circuit 13 ------Ground--------black wire------------"GND" CSync from----grey wire-------------"S" 78LS86 circuit No connection-yellow wire-----------"VS"