So, you consider yourself a sewing machine technician.
What exactly does that mean?
Does that mean you are a mechanic who gets his hands all greasy when you fix sewing machines? Maybe.
Does that mean you are a detective pursuing each clue until you diagnose the causes of sewing machine problems and then fix them? Maybe so.
Does that mean you are a specialist who helps sewing machine users by repairing their sewing machine, guiding the user to avoid future problems, and being ready to demonstrate how to get the most out of a given sewing machine? Ideally, yes.
To me the real difference here is one of understanding the sewing machine from the perspective of the sewing machine user. I believe a sewing machine technician needs to learn how to sew too. Many sewing machine technicians have never learned to sew anything. If you asked them to sew a basting stitch and then top stitch a seam; they might look at you and say, "I just fix 'em."
Here is my personal encouragement. Before you begin attempting to repair sewing machines, learn at least the basics of how to use them. Learn to sew. Sew out a few projects of your own. Understand how to sew. Master the basics of sewing, quilting, and the more common applications. Then you will be in a position to understand what is happening in a sewing machine from the perspective of the sewing machine user.
Why do sewers get so frustrated when the thread bunches up? If you sew even a little, you will understand.
Why do seweres get so upset when their seams wabble or they look at their finished project only to see a dozen skipped stitches? The better you understand the use of the sewing machine, the more effective you will be in empathizing, advising, and helping your customers.
Now that does not mean you have to make pretty frilly dresses, or feel weird because you are sewing. One of the projects I did was a wall hanging. It was simple, easy, and it look good when it was done. I admit, I got help from my wife. But when it comes to sewing she is definitely the main user.
Yet,when you have experienced the challenges and thrills of sewing as a user; you can better understand what is happening for the user. This can be a big help in diagnosing problems and providing solutions.
As you set out to learn sewing machine repair; besure to include learning how to sew as well.
Understanding the sewing machine user and appreciating their perspective with regard to their sewing machine will go a long way toward making your sewing machine repair more customer friendly.