Well, thanks for the input so far. I will explain the situation more deeply.
I bought my PS2 when I was in Japan last year in June, so I have the very first model (that right there could be the issue as I understand that the SCPH-10000 has several problems). Nevertheless, I haven\'t had any problems with it until I tried using a multitap.
I am using the PS2 multitap not the PSX. I have tried with all PS2 Dualshock controllers, all PSX controllers, and a combination of both. I have also tried two different PS2 multitaps thinking perhaps that one was bad.
I am trying to use the multitap with the following games: Street Fighter EX3 & Tekken Tag Tournament (both original Japanese version). In both cases, when I plug the multitap into the console, the multiplayer option (for more than two players) becomes enabled whereas before it wasn\'t. However, none of the controllers does anything. (i.e. Pushing the buttons or the direction pads gets no response from the console.)
I have tried plugging everything in before even giving the console power, plugging it all in after the game has booted, etc. But nothing seems to make a difference.
Basically I was wondering if anyone had heard anything like this happening before. I don\'t see why this should be happening, I mean usually peripherals are peripherals and regions don\'t matter. Two of my PS2 controllers are also from Japan but the others were bought here in the US and I don\'t have any problems with them.
Anyway, I think that just about fully describes the situation. If anyone knows anything that can help then I thank you in advance.