the video Bebe pointed us toward is helpful if you have a machine with a "stick-in" bobbin case. we have drop-in bobbins. it is possible to adjust the tension on a drop-in case. it is also a huge pain in the you-know-what.

you didn't mention how long you've had the machine or how many "miles" you've "driven" it since purchase or last service.

if you have already tried switching to a new needle of a larger size, and/or heavier thread in the bobbin, it may be time to take it in for a tension tune-up. i finally did that with my simplicity a few months ago and it has made a world of difference. i hated to spend the money, and i still think it cost too much, but i filed it under "what-the-heck-i-waste-more-than-that-on-pizza-delivery-and-fabric-i-definitely-didn't-need".

:?

Oh Patrice, you're asking more embarassing questions! LOL I bought this machine in either 2001 or 2002, at income tax return time. hehehe I have never taken it in for a tune up or service of any kind.

I used it a lot from the time of purchase until August 2005. Then I pretty much took a 3 year sewing hiatus, and started sewing again in August 2008. Those three years I was living in Hawaii and wasn't interested in sewing at all. Sooooo much else to be doing! :D