Ah okay, misunderstood your first post.

In that case, you could either wire up a DC jack and use an 18V DC pedal supply to power it or find a suitable replacement transformer to put in the enclosure.

There is an 78L15 regulator on board which regulates the voltage to 15V but it needs some extra voltage (about 1.7V if I recall correctly) to do its job and 18V is a fairly standard supply voltage that meets that criteria.

I mean a standard pedal power supply that supplies 18V from the wall voltage, one like this would work https://www.thomann.de/gb/pigtronix_18v_power_supply.htm

And then you’d have to fit one of these to where the cable used to come from and solder it to the board in the right place.
http://www.taydaelectronics.com/hardware/dc-power/dc-power-jack-2-1mm-enclosed-frame-with-switch.html

That should be fine, you’d just have to wire the DC jack the opposite way as it’s a positive tip.

I meant you’ll have to wire the lugs on this the opposite way to the other adapter as the EHX adapter is center positive instead of negative.

So where it says to board – you’d wire it to board +