C
olourMods The Single-Chip Colour Correction / Modchip SolutionThis mod is for the people who don't have a SCART lead and want to play imported games in colour on the SCPH-550X or earlier machine. Ifyou have a SCART lead and SCART TV, or a later PSX machine, then you DON'T NEED THIS module.
Disclaimer:
I must stress that this is not a project for beginners. It is too easy to irreparably damage your machine if you do not know exactly what you're doing. The author or provider of these pages cannot and will not assume responsibility for any damages that may occur while attempting this installation. You're on your own ;-)Module Overview
: The ColourMod solution is a small circuit based around the PIC12C508 MCU. T he circuit is quite simple. It is a crystal oscillator as supported by the PIC12C508's internal clock circuit. The key to its dual-purpose operation is in the crystal that determines the PIC's clock frequency. For PAL machines, this crystal has a value of 4.433619MHz. For NTSC machines, the value is 3.579545MHz. As with a "standard" modchip, the two signal lines (data and gate) are present, also the power supply leads. The colourburst frequency is taken from the crystal via a 4K7 resistor. Two 22 pF capacitors provide stability trimming for the oscillator; the 100 nF and the 10 uF capacitors provide decoupling. The module is cabled to the mainboard and this is not easy. Here is a schematic diagram of the circuit board, and CXA1645 connections, which are also displayed under the "Images" page..Freq = White, Gate = Yellow = pin 6 of chip, Data = Blue = pin 7 of chip, + 5 volts = Red = pin 1 of chip, - 5 volts = Black = pin 8 of chip
Mainboard Installation: CAUTION: If you are not experienced with circuit boards, PLEASE get expert help!
Firstly you will need to find the colour processor on your mainboard. The chip is located just below the AV connector and is the
CXA1645 chip. Now you must carefully lift pins 6 and 7 from the mainboard. Four of the PCB colourmod wires connect as a normal mod. The last wire which is the Freq wire goes to pin 6 on the CXA1645 chip, then solder a wire from pin 7 of the CXA1645 chip to the large square pad nearest to pin 1 of the CXA1645 chip. Now you can re-assemble your console and start playing NTSC games. Congratulations !