Q: I need a Macbook 4.1 adapter

They sell them at the online Apple Store.

They can match the correct adapter if you tell the Store your product

serial number, model, and product name; there also is an online guide

or article that covers most adapters, cords, etc.

•Intel-Based Apple notebooks: Identifying the right power adapter and power cord

Hopefully that's all it needs to work, once you get a replacement power

adapter, you should be able to tell if the battery is OK or needs renewal.

Good luck & happy computing!