Upper tension question
 

What are the signs and symptoms of needing a new take up spring?

Bent, pieces broken off, sticking up at weird angles, missing! Deliberately twisted. I've replaces a few. What machine are you thinking about? A lot of times I see machines with the perfectly good spring improperly installed. Get a repair manual and learn your stuff.

Miriam is a cool head with lots of experience. I marvel at her experience. Teach a man to fish and he can feed himself. That is the way with sewing machines. Learn your "stuff" and you can help others and further the lives of good old machines. We need more fixers every year.