First things first.
Check your connections. Are you plugged into the right jacks etc.
Does it work with a battery? (again, you said the LED works with the PSU, so if this works the PSU aint pumping out enough juice)
Check the unit with a mates PSU. (if it works, you're PSU aint pumping out enough juice )
If the LED comes on, its not a problem with the power jack, its probably something inside the unit or the PSU. But bear in mind, just because the PSU says its good for 300ma output, it doesn't mean it is.
As it works fine with the other (lower power) pedals, i'd say the psu aint pumping out enough juice. If you want a new one, the godlyke power all is good (1.7A output )
S