How To Check an Electrical Cord
A device may cease to function or operate sporadically if the electrical cord is damaged. Inspect the cord for any of the following damage.
Caution: Before inspecting a potentially damaged electrical cord, unplug it from the outlet, if it is safe to do so. Otherwise turn off the power at the circuit breaker or fuse box.
Is the wire shielding pulling away from the plug?
Is the cord secure where it connects to the device?
Are there black smudges or burn marks on the outlet, cord or anywhere the cord comes in contact?
Are there cracks in the shielding or exposed wire?
Has the cord been pinched or bent so that the wire inside may have broken?
If the answer to any of these questions is "yes", then the cord should be replaced.