Thanks for your thoughts everyone. I've been pretty good about keeping my machine clean and I did just oil the wick for the first time, just one drop though. It's been "thunking" since day one. Later this morning I'll go back and clean and oil it again and if that doesn't help will take it in for service. I've noticed that when I change needles the little arm you insert the needle into is wiggly, but is stable after I screw the needle in. Wonder if that is the problem?