My pedal is not powering on correctly. It seems to light up and then die, or otherwise isn't turning on at all.

While the majority of guitar pedals use 9V center negative power supplies, some models do vary in voltage, current, and even polarity specifications. Please double check you are using the correct power supply for your pedal, and that the total current draw for all your pedals is not overdrawing your power supply, which could lead to improperly powered and dysfunctional pedals.