Pfaff 2140 breaking top thread?

I have a Pfaff 2140 that keeps breaking the top thread when I use it for embroidery. I can hear a clicking sounds just before it breaks. Works fine for regular sewing. I’ve tried different threads, needles and bobbins, along with different stabilizers & materials and nothing seems to help with the embroidery thread breaking problem. Any ideas as to what is wrong with my machine? Oh this just started about a month ago and has been getting worse as I try and finish my embroidery project.