I have a 9v powerpack with 5 spaces and when I plug my pedal into the powerpack via 9v cabel it sometimes won't work, but if I change the cabel to a different space it will work, but if I turn the powerpack off and then turn it back on the pedal won't work.

So is it the my pedal that's dying or my powerpack?
are each of the 5 selections the same voltage rating or no?

these adapters are cheap so I would look up the specs on the internet and then go buy one from radio shack so you can do some process of elimination. Adapters fry all the time, especially cheap ones. Does your pedal work with just a 9v battery is another questions.

good luck