Music box

Today my mother let me have her old jewelry box which plays music with a dancing ballerina. It hasn't worked in 20 years. Once I displayed it in my room, I called my mum upstairs to come see it. When she was about half way up the stairs and I had my back to it, it played for about a second, and now it works again. It's been on continual for a couple of minutes now.

Do you think a fairy could of fixed it?