I have a Pfaff 2170.
The top thread has been breaking on me that past 2 days.
I've changed needle to a topstitch needle, I've rethreaded the machine again and again, etc.
So for a test, I thought I'd rethread again, lower the top tension to zero, and pull on the thread through the needle to see if it slid through easily.
It doesn't. It still has resistence with the presser foot up and/or down. Is that normal?