Universal is not a size thing. It means it can be used w both knits and wovens. Sharps are for wovens, ball points for knits and universal can do both. If you sew and hear a popping noise from the needle it's a sign that you need to change it.
Is the thread tangled underneath in one place or the whole seam?
If it's the whole swam it's probably a tension issue and you need to play around with the tension. Try this sew the fleece, then wo changing anything sew something you know the machine can handle. If the fleece is messed up but other ok it's a sign that you need to adjust the tension.
Another thought to try - put tissue paper between the pressure foot and fleece. Sometimes the foot is sticking a little bit and it causes the two pieces of fabric to move at different rates. The paper let's the foot glide a bit. You can sew thru the paper and then rip it away.
Last edited by AniMommy; 10-19-2012 at 04:42 AM.