The only time i had trouble with threads breaking with my embroidery Brother was when I changed my stabilizer. I always use a cheap one I get by the roll, no brand name, with no problem. When I switched to Steady Stuff by Ricky Tims, the thread broke every 2 seconds. Back to the cheap one, no broken thread. Just something else to look for.

How to get to tension discs Brother Quattro 2
 

This is an old thread but it still is relevant. I continually get thread stuck in the tension discs which leads to Birdsnest, thread shredding and thread breaking. I take it to a wonderful professional and they clean it out but it happens frequently enough that I would like to be able to fix it myself. I can’t find a video on YouTube that shows me how to open up the top part of the machine. Some of the newer and different makers have easy access to this part of the machine which will be kept in mind for my next upgrade. Has anyone opened this part of the machine before and do you have pictures or instructions on how to do it? And to put other questions to rest, I use high-quality thread, have no burrs or rough parts on any of my equipment including the lower parts of the machine. That’s been checked. It’s always the tension discs.
thank you.