I don't know how to loosen the 'tension wheel', have never done that before, although this sounds like it may solve the problem. I have used various different threads in both top and bobbin. Had it in for servicing about 5 months ago. This started happening about a month after that. Also, I use the needle down position, when I stop sewing, hit the button for the needle up - shouldn't that automatically put the take up lever all the way up?