Slim PS2 Compatability issue

a long time ago i bought a pelican real arcade joystick and later got the SF anniversary stick as a present. back then my first ps2 worked fine and so did the joysticks. after my ps2 crapped out, i bought another one, the slim one being the only ones left around and my joysticks dont work with it at all. i also borrowed a friends joystick and his works fine. my joysticks still work on the old ps2, and even works on another friend’s slim ps2. i dont get why it wont work with my slim ps2. is it the fact that mine is modded? is there like a way to mod my old joysticks to get them to work?

also, just throwing this out there, i’m planning to build a custom joystick, thing is i wanna use the perfect 360 joysticks for them. how would i go about getting that to work with the ps2?

if anyone can help at all that it would be much appreciated. any kind of help is welcome. suggestions, criticism anything. thanks again.