Thank you, everyone, for your replies. I hadn't thought about the possibility of a bad batch of check springs. Today I took my machine in to be repaired and was told Bernina will be releasing a new "assembly" (that's what I'm calling it but I'm not sure that is the correct word for it) which includes the check spring and which the owner can replace by removing just two screws. Sounds great to me if I correctly understood what I was told--but I don't guess this will be coming out for some time yet.
Last edited by saufroq1; 06-01-2019 at 11:22 PM.
Reason: clarify meaning