I just signed up for this FREE Craftsy class called "Sewing Machine 911". It's to teach beginners to advanced how to care for their machine and determine what is wrong should things not workout. Perhaps this could save some repair money with regular maintenance and a general knowledge and understanding of when help is indeed required instead of continuing on and making things worse (and more expensive!).
Let me know if you take the class and what you think of it!
Note: I am not in any way affiliated with Craftsy or this class but I wanted to share this great find with my readers.