First check, always, when loops on bottom is to check the take up lever....can't tell you how many times older Janomes had this problem....but other brands do too. When I was in a class one day, I heard a ladies machine and then her saying a few choice words...."my ......machine is messing up"....I immediately called out to her....Check your take up lever, has your thread slipped out.....she said yes. Janome finally started putting a little lock clip on the take up lever and it keeps the thread in.