Common question! Start at the spool and work forward. Put on an appropriate thread net, but only around the bottom 1/2″ of the spool. That’s right – I don’t let it come into contact with the thread because it can increase tension. I just want it around the plastic rim that makes up the bottom of the spool, which will prevent the thread from catching on a little notch the manufacturer has on this rim to help store the thread end when the thread isn’t being used. Tuck the rest of the net up into the spool and put it on the machine.
Also, make sure your thread spool is perfectly lined up with the take-up guide above it. If it isn’t completely aligned, the thread will drag on one side of the spool, causing a rubber band effect that can make the thread pop out of guides or tension devices.
Next, feel for burrs in the thread path that might be snagging the thread before it gets to the intermittent tension assembly (ITA).
The guide just in front of the ITA should be in a 3:00 position. Make sure you’ve threaded through it, around the bottom clockwise, then through it again. This will help the thread stay in place.
Finally, is the ITA too tight? Seems like you should tighten in down, but the opposite is true. Try loosening it. If the discs are too tight, it will actually push the thread out of the device.