(The backlash screw is located on the FRONT of the bobbin case and is even tinier than the tension screw. Adjust it and test every turn - about 2 minutes worth, until your bobbin rides just right. Test using letters O, T, M, and S - if all look good, your set.)
Thanks, Debbie, so much for your info. No one has ever told me about this backlash screw. I will certainly try this. I guess it's righty-tighty & lefty-loosey?