Ok, You tested the AC adapter and it’s dead. So it’s time to shop for a replacement AC adapter.  Original AC adapter cost 3 to 5 times more than a generic AC adapter.  Avoid generic AC adapter if all possible.  However, if you do decide to replace the original AC adapter with a generic one, you’ll have to follow this rule:

The voltage outpot on the replacement adapter has to be exactly the same as the original adapter.  The amperage on the new adapter could be the same or highter.