Is my magsave power adaptor dead? Last night, I heard a spark noise while my mac power adaptor was connected, and the charger stopped charging my machine. There was no light on the connector. I should also say that the cable attaching to the adaptor was torn. So after reading instructions for dismantling the charger, I cracked it open and cut the cable before the plastic  piece inside the charger. Then, I tested if the AC charger was having any output DC voltage with a multimeter. But it did not detect any. Now, do I have to assume that the unit is dead or is there some fuse which needs to be replaced?
There is a fuse in the charger, but replacing fuse is not recommended. 

And this is not the only surge protection unit. I recommend to test with another working charger and your mac and if your mac works well with another charger, then get another Apple charger.