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Yes, make sure it really is an adapter problem and not something else, but If you're still under warranty, be sure to keep that defective adapter and consider arranging an RMA through ASUS for only the adapter itself if you want to use it as a spare later.
If you don't want to wait for the RMA process, are located in the U.S. and wish to purchase from the U.S. eStore/eShop site check the link below.
http://store.asus.com/us/item/201506AM050000020/A47375-ASUS+230W+G-Series+Notebook+Power+Adapter
The 'boxed' 230w adapter pn 90XB01QN-MPW010 is sold in the U.S. through distribution as well although some resellers may not carry it or need to special order it.
If you prefer to purchase from your favorite ASUS authorized reseller, you can find the list of authorized U.S. resellers and distributors below, but just be aware many distributors probably don't sell directly to end-users.
http://promos.asus.com/us/where_to_buy/?_ga=2.257961290.1560060497.1509991668-481536228.1449680678
Hope this helps.