Try testing the fuse on the power supply with a multimeter for continuity
It could also be a blown diode on the power supply
You could test it live by taking off the back cover and testing these points if its working normally you will get 12 volts
http://case-modz.tk/Look at the ps2 case mod tutorials
I dont have a mulitmeter. My Ps2 doesn't even turn on at all, so I know I dont have any power going thru it unless you think it is possible still. Here is sumthing that has been bugging me, can I switch the ps1's fuse with ps2's, giving the ps2 power? I hope it works, because I would do it then. PLZ help some more, thanx.