I'm hoping you wonderful quilting buddies can help me out. My vintage electric singer, size 66 bobbin, is out of kilter. The tension was fine, then it wasn't. I was in the middle of quilting, and didn't move the machine, the dials, the thread, etc. I had it serviced recently and can take it back, but, would like to be able to solve these issues myself. I read the book, changed the thread, changed the bobbin, changed the needle. All is clean. All is correctly threaded. It is oiled and lubricated. The motor purrs. I can sort of get a good tension if I set the dial on 1 which doesn't seem right to me. What have I overlooked? Do these machines require other than a new Schmetz quilting needle?