i just got my 20x2 rack out of storage, where it's been sitting for a year in a metal briefcase, and i cannot get it to power on. i've swapped cables, tried different 9v power supplies, etc. i disconnected all of the other modules except an LFO because it has an LED that would let me know if i was getting anything. nothing.
Otherwise please make sure that the power supply is centre positive!
This is different from guitar pedal power supplies which are centre negative.
Turns out the power supply I had stored in the briefcase was the wrong one! as are all the others. the right one must still be in storage somewhere. i'll just buy another. thank you! i was too busy looking at the volts.