v4 ps2 magic 3.1-wont read dvd+or-r

[ps2_modz]

I have this version 4 ps2 with a magic 3.1 installed...the unit can read backup cdr real games and movies flawlessly but when it comes to backing up a game on a dvd-r or dvd+r it doesnt wanna read it. i tried adjusting the laser with no succesfull result. is it possible that some of the ver4 ps2 just cant read dvd+ or - r. or could it be a back modchip installation. if so what points should i be looking at.

Thanks for any info

ps2modz