[charlie_ps2]

I received this feedback from a US Messiah customer of mine (Alvin - thanks and well done).

The PSX NTSC FIX is just an electronic switch.
So I used a jumper on the wire V (see picture), brought to the outside of the PS2 case.

To play PSX games -----> jumper opened (V not used).
To play PS2 games -----> jumper closed (V used) .

This is a solution for people who don't have the FIX kit.

This advice is, of course, offered at your own risk.