Repairing a microwave at home is possible if you're sure what you're doing.
Just be careful because it's easy to get shocked and injured or possibly killed doing so.
Also make sure it's actually worth the cost of repairing the microwave as sometimes the parts cost as much or near as much as a brand new microwave.
For example if the microwave is a cheaper countertop microwave then the costs could far exceed the cost of a new microwave.
But if the microwave you have is a higher more expensive branded of microwave then the cost may be worth the repair parts.
I have the cheaper countertop microwave and if it goes out it's not worth the cost of the parts or the time to repair it.