I don't know if the 820 owners have the same "difficulty"
as 830 owners who need to thread the bobbin area differently for embroidery but I will provide this tip for lighting the bobbin area and usng the dental pick to see if the bobbin is threaded correctly. Some people have recommended a lighted dental pick which is cheaper than my solution. However I had a Bendable Bright Light left over from my 630 days sitting in a drawer since the lighting on the 830 is terrific. So I mounted it beneath the 830 table to light the area. No more 3 hands!
I put a photo in my profile.