if you've had any "broken needles" of jamming lately,,, it can be that the "timing" is off,,, ask me how i know??
just had a very severe accident wit the needle getting jammed and bent while in the down position... it's fixable, but by a tech... we've download lots of info and DH is a precision machinist, but some things are just left better to "the guy that does it all the time"... bring it to him :)