I have just removed a neo 4 and installed a home made magic 3 in my v4 ps2.
When I press the reset to switch the thing on the tray opens!!
the eject seems to have a mind of its own, sometimes it will work other times not.
Is the reset procedure the same as the magic 2 (hold reset for 2 secs to switch modes)?
I have tried a 33k , 16k resistor and a 15pf cap on the reset wire, which didn't seem to alter anything. I also removed the reset wire completely, and the tray still opened when I switched it on.
I did manage to get a ps2 game on cd and dvdr to boot occasionally though.