Not really fixing, more like preventive maintenance. Lubing one of my wife's sewing machines. This one is all mechanical vs the computer driven ones she also has. The shop gets a min $150 for this so it's worth my time to do it for her. I've even learned how to check the timing on them which they charge extra for.
This is my verification photo of the timing being correct.
Gotta just love doing macro photography while immersed in a good machine.