Waxing iron not heating up.

i got the dakine waxing kit last year and at one point i dropped the iron and the casing came off alittle. how ever it still worked and i used it over a dozen times last season. however over the summer i superglued the case back on but now it appear that the iron isnt heating up all the way. example: i use wax rated at like 140C but i have to crank it up to max just to get the wax to barely drip. this was not the case last year, even after it was dropped. any ideas? i thought it could be that the dial came off the connector knob inside that regulates temp which changed the reading but im pretty sure its something else. could it be the wall plug im using?