A few years ago I bought a used Bernina Artista Embroidery machine off of craigslist. I already had a relationship with the owners of the Bernina shop the owner of the machine had originally purchased it from.
Anyway, my auto needle threader gave me fits until the shop owner adjusted it. I use it ALL the time. It has spoiled me for when I use my vintage machines. I love it. Hopefully, yours just needs an adjustment or maybe a replacement. But, they are worth it. :-D