I'm having a difficult time trying to understand how a coiled 120V AC extension cord can be anything different that a straight one except for the increase in heat when a large current is passed through it. An extension cord is comprised of a hot, neutral, and ground. The electron flow between hot and neutral should cancel any inductance with the ground further dissipating the field of any magnetic inductance. My electronic knowledge is weak on magnetism but everything I read tells me a coiled extension cord delivers the same power and doesn't create any magnetic fields strong enough to effect anything.
Uncoiling a cord and having an inoperable device become operable could more likely be attributed to a break or weak part in the cord.
