Finally got the Mid Arm working!
 

I guess the Bernina 820QE is thread snobby, because it balked at everything except Superior. New bobbin, rethread and voila, I'm off to quilt-land. Lots still to learn - I didn't leave enough leader free on the take-up arm so couldn't get the stitch I wanted on the border, but those are lessons learned.

Got my first real quilt loaded on the frame and ready to roll - now I'm too tired to do anything tonight LOL.

Glad you got your problem solved. Tomorrow is another day and you have it all loaded, that is the least fun. Now for the real fun. I guess all machines are different when it comes to thread, I use Connecting Threads cotton for everything and haven't had any problems, knock on wood.

Have lots of fun. I can see that's going to be my next toy, cause doing FMQ on my DM ( with a short throat) is not too good with the issues with my arthritis.

Sounds like you have the problem solved. I love superior threads!!!! Remember you can always turn your quilts if you need to.