I think I FINALLY figured out at least one of my issues with my 780D---as I sat stitching out a sample for the repairman--I THINK I FINALLY found a knowledgeable person about 1 1/2 hours away---the machine did EVERYTHING---break thread, lose a screw down in the machine (I got it out), change needles, rechange needles, change thread, birds nest, Hubby's beard underneath, loopies on top, built in fonts bearding underneath and looping on top, changing upper tension, put in a different bobbin case (that one repairperson said was the "RIGHT ONE"---that caused the needle to embed down in the bobbin case and set off the alarm), reinsert the one that has the purple dot in it, you name it-----I pulled out on one of the birds nests without cutting the threads and found several pieces of upper thread caught up on the underside of the bobbin case---repeated it several stitches later----looked at it----a tiny nick that I thought was normal----looked at extra wrong bobbin case---it had no nick----put the purple dotted one back in and stitched a few more stitches--NO PROBLEM----so stopped while I was ahead----have a sample for the repair man AND all of the parts of the sample are written down so he can read what I did where!!!!!!!

Ordered a new bobbin case from the not-so-reliable repairperson---if she gets the right one I will try again---
if that does not work I will travel 1 1/2 hours (I'm still in a wheelchair from foot reconstruction surgery for 3 more weeks) to the next repairperson who is supposed to be good----he actually works on 8-12 emb machines per day and has a very good reputation----unlike the other lady who had not embroidered anything for 3-4 months---hello to me and duh to me---
I feel so much better after trying to stitch out a 4x4 butterfly for 2 hours and actually getting some evidence put together.....
God bless y'all:):):)