I also have the same Model 677 and I have yet to use it. My daughter bought it a year ago for my birthday (20.00) with a nice cabinet. It only has a knee pedal. Cleaned up really nice, Oiled it and it ran fine. I had the wiring redone and now it runs very slow. Not sure what could have happened. I took the old wire to a sew and vac place and they did a new cable for it. I might not be hooking it up correctly. I would love to be able to use it.