A while ago I came across a Jen Crybaby super, it came without a power supply, so i used my adjustable one, set it to 9V DC, plugged in guitar and amp, and it ran straight through, which I think means that the power was going through, but it wasn't adjusting the sound with the pedal, so there must be something wrong with the circuit.

I don't have the power supply any more, so i guess the first step would be to buy new battery/power supply, but knowing anything else i might need to buy would be helpful so i can go once, and know how much it will cost.

I know there's a long thread on modding wahs, but i'm a newbie in this field and i just would like to get it to work before modding.

thanks in advance
Check for bad solder joints (better yet just reheat them all and add a dab of new solder to each), loose connections (on the board and in the wiring), switch functionality, the connections of the battery snap (inside the black part and on the board), and clean all the oxidation off the jack contacts (windex works great) and clean the inside of the switch if there's a way to get the windex inside it without destroying the switch.

Then start taking voltage measurements to make sure the power is actually getting into the circuit.