Hi !

You can buy those adapters. Most of them are for sale at Amazon, example: https://www.amazon.com/Bose-Soundlink-Wi...

You could also contact the company, to check if they sell it.

I would rather buy a new one instead of fixing the old one. If the old one is fried, it’s difficult to find parts for the power adapter. Not sure why it’s fried, how old is the adapter? Did it became very hot? No water damage or something? And how is the wall outlet, still good?