Had similar probs once. Ready to beat up the dog or take my frying fan to the HQ in frustration! For me it was the fact that it was wrong needle. I thought the ones I p/u at JoAnns were fine and they seemed to work OK when I put them in. Later got very cranky. You have to use the German ones that come in the fancy case. Groz-Beckert. They are slightly longer and the shaft is slightly different(Had to come all the way to Chile to have a guy explain to me that this is like a commercial machine and it needs these special needles to be it's happiest!) They come from 110/18 and on down to 75's. They are more $$ so I didn't get them b4. Went for the cheaper ones assuming they's be ok.
Just a thot.