I have the same threading on the Brother 1500, identical machine to the Juki in threading. I noticed you threaded through two holes at the first thread guide. Try just threading through the last hole (from your right). That first thread guide is designed so each hole adds more thread tension. No where in the manual does it explain that at all and very few dealers know it. Also if you are using a thread stand have the pull out thread guide right over the thread cone, so the thread is coming straight off the cone not sideways.