Why many PSX games doesn´t run on my PS2???

[psx_paul]

when you say they dont run, do you mean that you can't get the game to boot up? or do you mean it boots but gets no further?

are you using the correct boot method for your magic 3 chip?

taken from the boot methods sticky post

Playstation 1 games & DVD Movies

• Power up from STANDBY with RESET button held until the blue EJECT light comes on; then release RESET and the disk will boot.

Does this solve your problem?